bc

Question 1

1.Which of the following amino acids supply the
atoms of positions 1,4,5 and 6 of the pyrimidine ring
in the de novo pyrimidine biosynthesis:
a) glycine
b) aspartate
2.c) glutamine
3.d) glutamate

Answer 1

aspartate

Question 2

In which the following catabolic processes amino acids are converted to the
corresponding α keto-acids (C-skeletons).
1) oxidative deamination
2) degradation of the carbon backbone
3) transamination
4) decarboxylation
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 2

b. 1+3

Question 3

Which of the following statements about the activation of the urea
cycle is
wrong:
a) urea cycle is activated during periods of fasting
b) the urea cycle is activated upon allosteric activation of the regulatory
enzyme (carbamoyl phosphate synthetase I) from N-acetyl-glutamate
c) the urea cycle is activated upon induction of the synthesis of enzymes
involved in the urea cycle
d) urea cycle is activated after meal with low protein content

Answer 3

d) urea cycle is activated after meal with low protein content

Question 4

Which of the following cofactors serve as prosthetic groups of the
enzymes aminoacidooxidases which catalyze the oxidative deamination
of amino acids:
1) NAD+
2) FMN
3) NADP+
4) FAD
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 4

b) 1 + 3

Question 5

For the synthesis of which of these molecules (neurotransmitters and
hormones) the amino acid tyrosine is not a precursor (substrate):
a) dopamine
b) serotonin
c) catecholamines (norepinephrine and epinephrine)
d) thyroid hormones

Answer 5

b) serotonin

Question 6

Which of the following statements about the synthesis of heme in
mammalian cells is true?
a)succinyl CoA and alanine are direct substrates for the formation of 5-
aminolevulinic acid (5-Ala)
b) Ferric ions (Fe3 +) are introduced into protoporphyrin IX
c) Coproporphyrin IV is an intermediate metabolite
d) Porphobilinogen is formed due to the condensation of 2 molecules of
5- Ale

Answer 6

d) Porphobilinogen is formed due to the condensation of 2 molecules of
5- Ale

Question 7

Patients with reduced intake of bilirubin from hepatocytes A) have an
increased level of “indirect” bilirubin in the blood B) have an increased
level of “direct” bilirubin in the blood
a) А
b) B
c) A and B
d) neither А nor B

Answer 7

d) neither А nor B

Question 8

In enzyme defect (deficiency) 5-Ala dehydratase (porphobilinogen
synthase) the following clinical signs are observed:
a) severe abdominal pains thrusts or
b) skin photosensitivity

a) А
b) B
c) A and B
d) neither А nor B

Answer 8

b.b

Question 9

In the synthesis of heme in mammalian cells:

1) Uroporphyrin III is the direct predecessor of coproporphyrin III
2) Ala-5 is formed by the condensation of succinyl CoA and valine
3) The ferric ion (Fe3 +) is introduced into the protoporphyrin IX before its
binding to globin molecule
4) Porphobilinogen formed due to the condensation of 2 molecules of 5-Ale
a)1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 9

b) 1 + 3

Question 10

In the metabolism of iron:

1) during the passage of the ferrous ions (Fe2 +) from the enterocytes in the
blood they are oxidized to ferric ions (Fe3 +) under the action of
tserulopazmin
2) the main transport protein of iron in plasma is hemosiderin
3) in the form of a complex with the protein ferritin iron accumulates in the
cells of the intestinal mucosa, liver, bone marrow
4) almost all of the iron from the diet is absorbed and excess is excreted in
the faeces
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 10

b) 1 + 3

Question 11

Increase in the blood of “direct” bilirubin is expected in:
1) hemolytic jaundice
2) low activity of Bilirubin-UDP-glucuronyl transferase as it is in infants
3) decreased hepatic intake of bilirubin (Gilbert syndrome)
4) biliary obstruction (blockage)
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 11

a) 1 + 2 + 3

Question 12

Ale synthetase:

1) requires pyridoxalphosphate for its activation
2) the synthesis of the enzyme may be induced by phenobarbital and some
of the steroids
3) suppressed by catarrh
4) is inhibited by lead
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 12

a) 1 + 2 + 3

Question 13

Thioredoxin is involved in:

a) the conversion of ATP into ADP
b) the conversion of dUMF into dTMF
c) the conversion of ribonucleotides into deoxyribonucleotides
d) the inhibition of xanthine oxidase

Answer 13

a) the conversion of ATP into ADP

Question 14

Which of the following mechanisms performes control the de novo synthesis
of pyrimidine nucleotides in humans:

1) negative feedback of glutamine-PRPP-amidotransferase
2) negative feedback of aspartate transcarbamoylase
3) availability of N-acetyl glutamate
4) availability of PRPP
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 14

d) 4

Question 15

Methotrexate is an inhibitor of dihydrofolate reductase. Its application
would inhibit:
1) de novo synthesis of UMP
2) conversion of dUMP into dTMP
3) conversion of IMP into GMP
4) de novo synthesis of IMP
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 15

c) 2 + 4

Question 16

Aspartic acid plays a role in all of the following processes with the
exception of one. Which is it?

a) de novo synthesis of AMP
b) the conversion of ATP into CTP
c) de novo synthesis of orotic acid
d) maintaining the pool (reservoir) of adenine nucleotides through
alternative pathways

Answer 16

c) de novo synthesis of orotic acid

Question 17

From the amino acid Trp (tryptophan) are obtained following biologically
important compounds

1) thyroxine
2) melanin
3) dopamine
4) melatonin
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 17

d) 4

Question 18

End products of the N-metabolism, which are excreted from the body
are:
1) urea
2) creatine
3) uric acid
4) acetoacetate
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 18

a) 1 + 2 + 3

Question 19

Metabolites of Ornithine cycle are:
1) succinyl CoA
2) citrulline
3) 5- Aminolevulinic acid
4) carbamoyl phosphate
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 19

c) 2 + 4

Question 20

Pyrimidines degradation products are:
1) b-aminoisobutyrate
2) urea
3) b-alanine
4) orotic acid
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 20

d) 4

Question 21

Regulatory enzymes of purines de novo synthesis are:
1) xanthine oxidase
2) PRPP amidotransferase
3) adenine phosphoribosyltransferase
4) adenilosuccinate synthetase
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 21

d.4

Question 22

Which of the following enzymes is defective in patients with Lesch-Nyhan
syndrome?

a) adenosine deaminase
b) adenine phosphoribosyltransferase (АPT)
c) xanthine dehydrogenase (oxidase)
d)hypoxanthineguaninephosphoribosyltransferase (HGPRT)

Answer 22

d)hypoxanthineguaninephosphoribosyltransferase (HGPRT)

Question 23

Which of the following groups of amino acids can be classified as “non-
essential”?

a) Ala, Glu, Ile, Pro
b) Asn, Cys, Pro, Tyr
c) Ast, Ser, Thre, Tyr
d) Ala, Gln, Gly, Trp

Answer 23

b) Asn, Cys, Pro, Tyr

Question 24

Tetrahydrobiopterin is required to:
a) methylation of dUMP
b) degradation of Tyr
c) hydroxylation of phenylalanine
d) transfer of one-carbon groups (fragments)

Answer 24

c) hydroxylation of phenylalanine

Question 25

Hereditary metabolic disorder known as Phenylketonuria (PKU):

a)is usually due to a hereditary defect of the enzyme phenylalanine
hydroxylase
b) is related to a high level of phenylalanine and tyrosine in blood
plasma
c) manifests in young boys
d) associated with blond hair and a light tan because phenylalanine
inhibits the production of melanin

Answer 25

a)is usually due to a hereditary defect of the enzyme phenylalanine
hydroxylase

Question 26

Which of the following amino acids are precursors in the synthesis of
creatine phosphate?

1) Glycine
2) methionine
3) arginine
4) glutamine
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 26

b) 1 + 3

Question 27

Transamination reactions require one of the following vitamins
a) riboflavin
b) pantothenate;
c) thiamine;
d) pyridoxol;

Answer 27

d) pyridoxol;

Question 28

Which of the following vitamins is a precursor of prosthetic groups of
transaminases?

а) thiamine
b) pyridoxine
c) niacin
d) riboflavin

Answer 28

b) pyridoxine

Question 29

In which of the following diseases is observed increased levels of
GOT(АsАТ)?.
1. obstructive jaundice
2. viral hepatitis
3. brain stroke
4. cardiac infarction
a) 1+2+3
b) 1+3
c) 3+4
d) 1+2+4

Answer 29

d) 1+2+4

Question 30

Which of the following enzymatic defects is responsible for the Crigler-
Naijar syndrome?

а) argininosuktsinat synthetase deficiency
b) bilirubin UDP-glucuronyl-transferase deficiency
c) Pal-hydroxylase deficiency
d) biopterin synthase deficiency

Answer 30

b) bilirubin UDP-glucuronyl-transferase deficiency

Question 31

Reactions of disposal of ammonia in peripheral tissues are
1) glutamine synthase reaction
2) urea synthesis
3) reductive amination of alpha-ketoglutarate
4) amidoacidooxidase reaction
a) 1 + 2 + 3
b) 1 + 3
c) 2 + 4
d) 4

Answer 31

b) 1 + 3

Question 32

Which of the following compounds is obtained from tryptophan as one
of the reactions in its synthesis is a reaction of decarboxylation?
a) dopamine
b) melatonin
c) epinephrine
d) histamine

Answer 32

b) melatonin

Question 33

Which of these amino acids is only ketogenic amino acid?
а) tryptophan
b) leucine
c) isoleucine
d) alanine

Answer 33

b) leucine

Question 34

Which of the following enzymes catalyze reactions of disposal (fixing) of
ammonia?

1. glutamate dehydrogenase
2. carbamoyl phosphate synthetase
3. glutamine synthetase
4. glutaminase
   а) 1+2+3
   b) 2+3
   c) 2+4
   d) 1+2+4

Answer 34

c) 2+4

Question 35

Which of the following reactions from Ornithine cycle is endergonic
and requires ATP?
а) ornithine transcarbamoylase
b) argininosuccynate synthetase
c) argininosuccynate lyase
d) arginase

Answer 35

c) argininosuccynate lyase

Question 36

Which of the following compounds accumulate in the blood and is
excreted in the urine in argininosuccynate synthetase block?
a) arginine
b) argininosuccynate
c) citrulline
d) ornithine

Answer 36

a) arginine

Question 37

37. To which of the following metabolites some of glycogen amino
    acids are degraded?
38. pyruvate
39. acetoacetate
40. oxaloacetate
41. fumarate
    a) 1+2+3
    b) 2+3
    c) 2+4
    d) 1+3+4

Answer 37

d) 1+3+4

Question 38

Which of these amino acids is only ketogenic amino acid?

а) tryptophan
b) leucine
c) isoleucine
d) alanine

Answer 38

b) leucine

Question 39

In block of which of the following enzymes develops classical
phenylketonuria?

a) homogentisate oxidase
b) tyrosine transaminase
c) dihydrobiopterin reductase
d) phenylalanine hydroxylase

Answer 39

d) phenylalanine hydroxylase

Question 40

Which of the following biologically important compounds are byproducts
from the metabolism of tryptophan?

1. thyroxine
2. melatonin
3. melanin
4. serotonin
   a) 1+2+3
   b) 2+3
   c) 2+4
   d) 1+3+4

Answer 40

c) 2+4

Question 41

Which of the following enzymes involved in the synthesis of heme is the major
regulatory enzyme regulated by the type of feedback at the genetic level?

a) aminolevulinate dehydratase
b) aminolevulinate synthase
c) uroporphyrinogen III co-synthase
d) uroporphyrinogen decarboxylase

Answer 41

b) aminolevulinate synthase

Question 42

Which of the following biologically important compounds are byproducts
from the metabolism of tyrosine?

1. thyroxine
2. melatonin
3. melanin
4. dopamine
   a) 1+2+3
   b) 2+3
   c) 2+4
   d) 1+3+4

Answer 42

d) 1+3+4

Question 43

Which of the following one-carbon groups bind to tetrahydrofolic acid
(FAH4) is the most reduced (C atom has the lowest oxidation state)?

a) formyl (N10- formyl -FAН4)
b) methyl (N5- methyl -FAН4)
c) methylene (N5 ,N10- methylene -FAН4)
d) formimine (N5- formimine -FAН4)

Answer 43

b) methyl (N5-methyl-FAH4)

Question 44

Which of the following compounds are byproducts, not precursors in the
synthesis of heme?

1. 5-Aminolevulinic acid
2. coproporphyrinogen I
3. porphobilinogen
4. uroporphyrinogen I
   a) 1+2+3
   b) 2+4
   c) 2+3
   d) 1+3+4

Answer 44

b) 2+4

Question 45

Which of the following substituents and sequence of these substituents at
pyrrole ring are found in the precursor of heme coproporphyrinogen?
A – acetyl
P – propionyl
M – methyl
V - vinyl
a) MB МV МP PМ
b) МP МP МP МP
c) МP МP МP PМ
d) АP АP АP PА

Answer 45

d) АP АP АP PА

Question 46

50. In which the following catabolic pathways of amino acids “biogenic
    amines” are produced as end products:
    a) oxidative deamination
    b) transamination
    c) cleavage of the carbon backbone
    d) decarboxylation

Answer 46

a) oxidative deamination

Question 47

Which of the following enzymes are involved in the degradation of
heme and the production of unconjugated bilirubin?

1) UDP- glucuronyl transferase
2) hemoxigenase
3) biliverdin reductase
4) bilirubin monoglucuronide mutase
a) 1+2+3
b) 2+4
c) 2+3
d) 1+3+4

Answer 47

c) 2+3

Question 48

Defect (complete absence of activity) of which of the following

enzymes is responsible for the development of the disease Crigler-
Najjar I?

а) UDP- glucuronyl transferase
b) hemoxigenase
c) biliverdin reductase
d) bilirubin monoglucuronide mutase

Answer 48

а) UDP- glucuronyl transferase

Question 49

Which of the following compounds is a bile pigment found in the urine
in mechanical (obstructive) jaundice?
a) urobilinogen
b) sterkobilinogen
c) conjugated bilirubin
d) unconjugated bilirubin

Answer 49

c) conjugated bilirubin

Question 50

Considering that the zymogen forms represent the inactive enzyme
digesting dietary proteins, which of the following zymogens is not
converted into active enzyme by the action of trypsin:
a) chymotrypsinogen
b) pepsinogen
c) proelastase
d) procarboxypeptidase

Answer 50

b) pepsinogen

Question 51

Which of the processes listed below is not endergonic?

А. muscle contraction
B. transportation of compounds along the concentration gradient
C. transmission of a nerve impulse
D. maintaining of a concentration gradient

Answer 51

D. maintaining of a concentration gradient

Question 52

Which of the following statements related to the Second law of the
Thermodynamics is wrong?

A. Naturally all processes proceed in the direction leading to a maximum disorder.
B. A system is in equilibrium (is most stable) when the Enthalpy has a maximum value
C. The systems in equilibrium have maximum Entropy.
D. The magnitude, characterizing the change of energy that can do work is the Free energy

Answer 52

B. A system is in equilibrium (is most stable) when the Enthalpy has a
maximum value

Question 53

The standard redox potentials (Ео’) of the redox systems NAD+/NAD.H and
pyruvate/lactate are: Eo = -0,32 V and Eo = -0,19 V, respectively. Which of the following
statements is wrong?

A. Under standard conditions, pH 7 and equimolar concentration of 1M of all
components of the systems, the redox system NAD+/NAD.H has a greater ability to
give electrons than the redox system pyruvate/lactate.
B. Under standard conditions, pH 7 and equimolar concentrations of 1M of all the
substances, the electrons flow from NAD.H to pyruvate.
C. If at the beginning of the reaction the concentration of all substances is 1M, and the
pH=7, the reversible reaction: pyruvate + NAD.H+H+ lactate + NAD+, will run from
left to right
D. If at the beginning of the reaction the concentration of all substances is 1M, and the
pH=7, the reversible reaction: pyruvate + NAD.H+H+ lactate + NAD+, will run from
right to left

Answer 53

B. Under standard conditions, pH 7 and equimolar concentrations of 1M of all the
substances, the electrons flow from NAD.H to pyruvate.

Question 54

When you consider the standard redox potentials (Eo’) on
these three redox systems:

1) Cytochrome.b6 (Fe3+)/ Cytochrome b6 (Fe2+) - Eo’= - 0,06V
2) Cytochrome f (Fe3+)/ Cytochrome f (Fe2+) - Eo= + 0,365V
3) Ferredoxin (oxidized)/ Ferredoxin (reduced) - Eo= - 0,432V
which of the following redox chains is correct? А. 1, 2, 3
B. 1,3,2
C. 3, 2, 1
D. 3, 1, 2

Answer 54

C. 3, 2, 1

Question 55

5. Which of the following bonds are rich in energy (macroergic)?
   1) thioester bonds
   2) phosphosulfate bonds
   3) pyrophosphate bonds
   4) phosphodiester bonds
   А: 1+2+3
   B: 1+3
   C: 2+4
   D: all four

Answer 55

D: all four

Question 56

6. Which of these magnitudes and values determine the standard free energy of an
   oxidoreductase process?

1) The number of electrons transferred during the reaction
2) The Faraday constant (F)
3) The difference between the normal redox potentials of redox systems 4) The
universal gas constant (R)
А: 1+2+4
B: 1+3+4
C: 1+2+3
D: all four

Answer 56

B: 1+3+4

Question 57

7. Which of the following types of oxidoreductases have most
   often Vit B2 derivatives as cofactors?

A. Peroxidases
B. Oxidase
C. Monooxygenase
D. Anaerobic dehydrogenases

Answer 57

B. Oxidase
C. Monooxygenase

Question 58

8. Which of the following enzymes is involved in the elimination of
   H2O2?

• A: Glutathione peroxidase
• B: Superoxide dismutase
• C: Glutathione reductase
• D: Ham oxygenase

Answer 58

• A: Glutathione peroxidase
• B: Superoxide dismutase

Question 59

9. The listed cytochromes are involved in the respiratory chain in mitochondria.
   There is only one exception. What is that exception?

А: Cytochrome с1
B: Cytochrome с
C: Cytochrome b5
D: Cytochrome а3

Answer 59

C: Cytochrome b5

Question 60

10. Which of the listed redox systems of biological interest is a quinine
    redox system?

A: NAD+/NAD.H
B: Glutathione
C: Vitamin С
D: Coenzyme Q

Answer 60

A: NAD+/NAD.H

Question 61

11. Which of the listed redox systems of biological interest is a thiol
    redox system?
    А: Glutathione
    B: FAD
    C: NAD+
    D: Vitamin С

Answer 61

D: Vitamin С

Question 62

Which of the following oxidoreductases function only as
anaerobic dehydrogenases?

А: the enzymes cooperated with flavonic redox system (FAD or FMN)
B: the enzymes cooperated with nicotinamide redox systems (NAD+ or NADP+)
C: oxidases
D: oxygenases

Answer 62

B: the enzymes cooperated with nicotinamide redox systems (NAD+ or NADP+)

Question 63

Which of the following oxidoreductases are monooxygenases?
1) Cytochrome oxidase
2) Phenylalanine hydroxylase
3) Tryptophan oxygenase
4) Tryptophan hydroxylase
A: 1+2+3
B: 1+3
C: 2+4
D: only 4

Answer 63

C: 2+4

Question 64

Which of the following substances are direct hydrogen donors in the
processes catalyzed by peroxidases for elimination of H2O2 and/or
hydroperoxides?

1) Ascorbic acid (Vit С)
2) Tocopherols (Vit E)
3) Glutathione
4) NADP.H
А: 1+2+3
B: 1+3
C: 2+4
D: all four

Answer 64

B: 1+3

Question 65

Which of the following substances is a specific inhibitor of the
electron transport performed by the complex IV of the respiratory
chain?

A. Oligomycin
B. Atractiloside
C. Malonate
D. CO

Answer 65

D. CO

Question 66

Which of the listed process in the respiratory chain will be inhibited
in the presence of the antibiotic oligomycin?

A. Cell respiration (redox processes in the respiratory chain)
B. Transfer of phosphate ions through the inner mitochondrial
membrane
C. Transfer of ADP/ATP through the inner mitochondrial membrane
D. Synthesis of ATP

Answer 66

D. Synthesis of ATP

Question 67

Indicate which of the following inhibitors of oxidative
phosphorylation in respiratory chain inhibite the transport across the
inner mitochondrial membrane of ATP and ADP:

А: Atractyloside
B: Rotenone
C: Oligomycin
D: Malonate

Answer 67

C: Oligomycin

Question 68

The truncated (short) electron transport chains involved in the
process of hydroxylation with Cytochrome P450 (CYP) are located
mainly in one type of the listed subcellular structures. Which are those
structures?

А: lysosomes
B: peroxisomes
C: nuclei
D: endoplasmic reticulum

Answer 68

D: endoplasmic reticulum

Question 69

Indicate which of the following compounds is an uncoupling agent
of oxidative phosphorylation in the respiratory chain?

А: Rotenone
B: 2,4-dinitrophenol
C: Oligomycin
D: Atractyloside

Answer 69

C: Oligomycin

Question 70

All listed enzymes, except for only one type, are flavoproteins
(FAD/FMN-associated dehydrogenases):

A: D-amino acid oxidase
B: malate dehydrogenase
C: NAD+-dehydrogenase
D: succinate dehydrogenase

Answer 70

B: malate dehydrogenase

Question 71

Which of the following processes are processes of “free oxidation”:

1: hydroxylation with Cytochrome Р450 (CYPs)
2: oxidation of glyceraldehyde 3-phosphate
3. oxidative deamination of amino acids
4: oxidation of lactate
A: 1+2+3
B: 1+3
C: 2+4
D: none of them

Answer 71

D: none of them

Question 72

Which of the listed processes leads to elimination of the superoxide
anion radicals:

А: reaction catalyzed by NADPH-oxidase
B: spontaneous oxidation of hemoglobin
C: reaction catalyzed by superoxide dismutase
D: reaction catalyzed by xanthine oxidase

Answer 72

C: reaction catalyzed by superoxide dismutase

Question 73

25. In which of the listed subcellular structures the enzyme catalase is
    localized?

А: peroxisomes
B: lysosomes
C: mitochondria
D: nuclei

Answer 73

А: peroxisomes

Question 74

Which of the following statements concerning ubiquinone (Q) is wrong?

A: In its reduced form, the coenzyme Q (ubiquinone) reacts with Fe-S complexes of ubiquinone- cytochrome c oxidoreductase and transfers one electron on them.
B: The quinone structure of the molecule can bind one electron forming condition
called free radical semiquinone.
C: In the respiratory chain it is reduced by the ubiquinone-cytochrome c
oxidoreductase and is oxidized by cytochrome c oxidase
D: In mammals its molecule typically has a hydrophobic “tail” made up of 10
isoprene residues

Answer 74

A: In its reduced form, the coenzyme Q (ubiquinone) reacts with Fe-S complexes of ubiquinone- cytochrome c oxidoreductase and transfers one electron on them.

Question 75

NAD+ and Ubiquinone (Q) serve as collectors of reducing equivalents released
during the dehydrogenation of a variety of substrates. These reducing equivalents
further are transmitted from reduced ubiquinone (QH2) in the respiratory chain to
cytochromes. Indicate which of the listed metabolites are oxidized in the
mitochondria yielding NAD.H, which is a major substrate of respiratory chain.

1: isocitrate
2: glycerol-3-phosphate
3. malate
4: succinate
A: 1+2+3
B: 1+3
C: 2+4
D: all four

Answer 75

B: 1+3

Question 76

All lised chemical bonds are macroergic except one. Which is that
bond?:

А: Pyrophosphate bond
B: Thioester bond
C: Enolphosphate bond
D: Glycosidic bond

Answer 76

D: Glycosidic bond

Question 77

Which of the following processes are processes of free oxidation:

1: hydroxylation with Cytochrome Р450 (CYPs)
2: oxidation of hypoxanthine
3. oxidative deamination of amino acids
4: oxidation of glyceraldehyde 3-phosphate
A: 1+2+3
B: 1+3
C: 2+4
D: none of them

Answer 77

D: none of them

Question 78

Which of the following substances carry out their antioxidant function
mainly by reduction of tocopheryl radical to tocopherol?

1: b-carotene
2: Vitamin C
3: Vitamin A
4: flavonoids
A: 1+2+3
B: 1+3
C: 2+4
D: all of them

Answer 78

B: 1+3

Question 79

Which of the listed processes does not lead to production of
superoxide anion radical:

A: reaction catalyzed by NADPH-oxidase
B: spontaneous oxidation of hemoglobin
C: reaction catalyzed by superoxide dismutase
D: reaction catalyzed by xanthine oxidase

Answer 79

C: reaction catalyzed by superoxide dismutase

Question 80

Choose the correct statement, referring to the eukaryotic
mitochondrial ATP synthase complex

A: ATP from ADP and inorganic phosphate (Pi) is synthesized in the F1 fragment
B: The electron microscopic observations show that the F1 fragment of the
complex binds to the transmembrane Fo fragment and it is placed on the outer side of the inner mitochondrial membrane
c: The antibiotic oligomycin binds the Fo fragment and inhibits the flow of H+
out of mitochondria
D: The synthesis of ATP is carried out in the F1 fragment of the complex, and
it is a result of oxidative phosphorylation of substrate level

Answer 80

c: The antibiotic oligomycin binds the Fo fragment and inhibits the flow of H+ out of mitochondria

Question 81

The adding of 2,4-dinitrophenol to the active “breathing”
mitochondria causes the effects given below except one of them.
Which is that exception?

А: [NAD+] is increased
B: There is enhancement of ATP production
C: There is enhancement of О2 consumption
D: Annulling of proton (H+) gradient

Answer 81

B: There is enhancement of ATP production

Question 82

Indicate which of these cytochromes are not involved in the
truncated (microsomal) electron- transfer chains:

1: Cytochorme b5
2: Cytochrome c
3: Cytochrome Р450
4: Cytochrome а3
А: 1+2+3
B: 1+3
C: 2+4
D: all of them

Answer 82

C: 2+4

Question 83

Which of the following statements concerning respiratory chain is
wrong?

A: Ubiquinone is a lipid-soluble component of respiratory chain.
B: The reduction of molecular O2 is performed in Cytochrome c oxidase
complex.
C: The arrangement of the redox systems in respiratory chain enables the transmission of electrons from NAD.H+H+ and FAD.H2 to O2, which otherwise is thermodynamically impossible
D: The two enzymes: NAD.H - dehydrogenase and Succinate
dehydrogenase transfer electrons to coenzyme Q (ubiquinone).

Answer 83

C: The arrangement of the redox systems in respiratory chain enables
the transmission of electrons from NAD.H+H+ and FAD.H2 to O2, which
otherwise is thermodynamically impossible

Question 84

Which of the following statements related to Cytochrome c is
wrong?

A: It has a standard redox potential lower than Cytochrome a3
B: Binds one electron and becomes oxidized
C: Participates in redox processes by transferring one electron
D: Connects protein complexes III and IV in respiratory chain

Answer 84

A: It has a standard redox potential lower than Cytochrome a3

Question 85

Choose the wrong statement concerning chemioosmotic mechanism for coupling of
oxidation in respiratory chain and phosphorylation of ADP.

A: The main protein complexes of respiratory chain in mitochondria carry out pumping H+
from the matrix into intermembrane space.
B: The transmembrane pH gradient in mitochondria may be reduced and annulled by DNP
(2,4- dinitrophenol), which brings protons across the inner membrane
C. The pH within the mitochondrial matrix is lower than in the intermembrane space of mitochondria.
D: The energy of the electrochemical H+ gradient across the inner mitochondrial membrane
is the one that drives the synthesis of ATP

Answer 85

C. The pH within the mitochondrial matrix is lower than in the intermembrane space of mitochondria.

Question 86

Which of the following statements is wrong?

A: The change of the free energy that is released as a result of the hydrolysis of 1 mol ATP to 1 mol ADP and 1 mol inorganic phosphate (Pi) is 30.5 kJ (7 kkal).
B: Thermodynamically unfavorable reactions (endergonic) may occur
due to conjugation with thermodynamically favorable (exergonic)
reactions
C: In equilibrium free energy change G is always <0
D: The total change of free energy of chemically coupled processes is equal to the sum of the changes of the free energy of each of the reactions.

Answer 86

C: In equilibrium free energy change G is always <0

Question 87

Free oxidation is important for some of the processes listed below. Which
are they?

1) thermogenesis
2) synthesis of steroid hormones
3) metabolism of xenobiotics
4) metabolism of aromatic amino acids
А: 1+2+3
B: 1+3
C: 2+4
D: all four

Answer 87

B: 1+3

Question 88

Which of the following characteristics and functions are not specific
for ubiquinone (coenzyme Q)?

A collector of reducing equivalents
B. uncoupling of oxidative phosphorylation in the respiratory chain
C. transfer of H+ in membranes - mitochondrial, lysosomal, plasma
membrame
D. antioxidant role

Answer 88

B. uncoupling of oxidative phosphorylation in the respiratory chain

Question 89

The following features are characteristical of the brown adipose
tissue. The exception is one of them. Which is that?

A. The tissue is highly vascularized.
B. There is high activity of ATP-synthase
C. The adipocytes are small, polygonal and have many mitochondria
with a large amount of cytochromes
D. In inner mitochondrial membrane a protein called termogenin is
localized which has a role of proton channel.

Answer 89

B. There is high activity of ATP-synthase

Question 90

The Fo-F1 complex in mitochondria is important for one of the
following processes. Which is that?

А: Oxidation of NAD.Н to NAD+
B: Obtaining of ATP from AMP and Pi
C: Transport of Н+ out of the mitochondria
D: Obtaining of ATP from AMD and Pi

Answer 90

D: Obtaining of ATP from AMD and Pi

Question 91

Which of the following statements is true?

A: In respiratory chain Cytochrome c can transfer simultaneously 2
electrons
B: The compound, 2,4-dinitrophenol, uncouples the oxidative
phosphorylation by annulling the H+ gradient on both sites of the inner
mitochondrial membrane
C: CN- inhibit Cytochrome c.
D: The chemical substances, rotenol and amitalat, specifically inhibit
cytochrome oxidase

Answer 91

C: CN- inhibit Cytochrome c.

Question 92

Which of the following statements is true for chemiosmotic hypothesis of
Mitchell?

A: There is chemical conjugation (coupling) of oxidation of NAD.H with ATP
synthesis
B: There is synthesis of ATP during the flow of H+ along their concentration
gradient across the inner mitochondrial membrane to the matrix
C: There is formation of macroergic intermediate compound during
transmission of eletrons
D: There is generation of pH gradient on both sides of the outer
mitochondrial membrane

Answer 92

B: There is synthesis of ATP during the flow of H+ along their concentration
gradient across the inner mitochondrial membrane to the matrix

Question 93

Which of the following compounds contain macroergic bonds and are
macroergic?

1: enolphosphate
2: succinyl-CoA
3: 1,3- bisphosphoglycerate
4: AMP
a: 1+2+3
b: 1+3
c: 2+4
d: all four

Answer 93

d: all four

Question 94

The free energy obtained in respiratory chain can be used in
mitochondria for one of the following processes.

А: generation of heath
B: transport of ions
C: ATP synthesis
D: all of the above

Answer 94

C: ATP synthesis

Question 95

Which of the following statements concerning the synthesis of ATP
in the mitochondria is not true?

A: ATP-synthase is oligomeric protein comprising 3 domains - transmembrane, intramatrix and associated domains
B: ATP synthase has oligomycin binding site

C: ATP-synthase is inhibited directly from CN-
D: ATP synthase catalyses the phosphorylation of ADP when H+ flows

through the complex from intermembrane space to the the
mitochondria

Answer 95

C: ATP-synthase is inhibited directly from CN-

Question 96

Which of the following statements related to Cytochrom c is
wrong?

A: It is the only electron-transport protein that can be physically
separated from the inner mitochondrial membrane
B: It has a standard redox potential lower than Cytochrom a3
C: Participates in the process of apoptosis
D: Connect protein complex II and III of respiratory chain

Answer 96

D: Connect protein complex II and III of respiratory chain

Question 97

Which of the following processes are involved in the process of heat production in cold
weather effects?

1) There is stimulation of the synthesis and secretion of thyroid hormones and noradrenaline
2) There is stimulation of lipolysis in adipose tissue
3) There is activation of adenylate cyclase, protein kinase A and hormone-sensitive lipase
4) There is coupling of the cellular respiration and oxidative phosphorylation
А: 1+2+3
B: 1+3
C: 2+4
D: all four

Answer 97

А: 1+2+3

Question 98

Which of the following enzymes, involved in the breakdown of carbohydrates
in the digestive tract of humans, has/have small intestine origin?

1) sucrase
2) glucoamylase 3) lactase
4) α- amylase
a)1+2+3
b)1+3
c)2+4
D) 4

Answer 98

b)1+3

Question 99

The absorption of glucose through the mucous membrane of
enterocytes in the human is performed via one of the listed types of
transport proteins. Which is that?

a) glucose transporter type 2 (GLUT2)
b) glucose transporter type 5 (GLUT5)
c) Na-dependent glucose transporter (SGLT1)
d) glucose transporter type 1 (GLUT1)

Answer 99

c) Na-dependent glucose transporter (SGLT1)

Question 100

Which of the following co-enzymes does not participate in the pyruvate
dehydrogenase complex:

a) pyridoxalphosphate
b) thiamine pyrophosphate
c) coenzyme-A
d) lipoic acid

Answer 100

a) pyridoxalphosphate

Question 101

Which of the following enzymes involved in the glycolysis is the major
regulatory enzyme of this pathway:

a) Phosphofructokinase-2 (PFK-2)
b) Aldolase
c) Phosphoglycerate kinase
d) Phosphofructokinase-1 (PFK-1)

Answer 101

a) Phosphofructokinase-2 (PFK-2)

Question 102

Which of the following metabolites is not an allosteric modulator of the
main regulatory enzyme of glycolysis:

a) ATP
b) Glucose-6-phosphate
c) AMP
d) Fructose-2,6-bisphosphate

Answer 102

b) Glucose-6-phosphate

Question 103

In which of the following cells the anaerobic glycolysis is performed:

1) white muscle fibers (during active contraction)
2) cells of the renal medulla
3) erythrocytes
4) cells of the eye lens
a) 1+2+3
b) 1+3
c) 2+4
d) 1+2+3+4

Answer 103

b) 1+3

Question 104

Which of the following substances is a direct product of the action of
the enzyme glycogen phosphorylase (glycogenolysis):

a) Glucose-6-phosphate
b) Glucose
c) Glucose-1-phosphate
d) None of the mentioned above

Answer 104

c) Glucose-1-phosphate

Question 105

Which of the following enzyme catalyzes the conversion of glucose to
glucose-6-phosphate in muscle cells:

a) Glucose-6-phosphatase
b) Glucokinase
c) Phosphoglucomutase
d) Hexokinase

Answer 105

d) Hexokinase

Question 106

Which of the following enzymes uses NAD.H as coenzyme in reduction
process in anaerobic glycolysis:

a) Pyruvate kinase
b) Enolase
c) Lactate dehydrogenase
d) Glyceraldehyde-3-phosphate dehydrogenase

Answer 106

c) Lactate dehydrogenase

Question 107

Which of the following statements about the malate-aspartate shuttle
is not true:

a) The shuttle is bidirectional
b) Cytoplasmic and mitochondrial malate dehydrogenases participate in the
shuttle
c) The oxidation in the respiratory chain of the two pairs of reducing
equivalents transferred by the shuttle mechanism, leads to the synthesis of
4 ATP molecules
d) The pair of substrates involved in the shuttle are oxaloacetate and malate

Answer 107

c) The oxidation in the respiratory chain of the two pairs of reducing
equivalents transferred by the shuttle mechanism, leads to the synthesis of
4 ATP molecules

Question 108

Select the correct answer of the question: In how many ATP molecules
the energy released from the anaerobic glycolysis is accumulated?

a) Two
b) Eight
c) Thirty six
d) Four

Answer 108

a) Two

Question 109

Which of the following enzymes are involved in the first, non-oxidizing
phase of the glycolytic pathway?

1) phosphohexosoisomerase
2) phosphofructokinase 1
3) hexokinase
4) enolase
a) 1+2+3
b) 1+3
c) 2+4
d) All of the mentioned above

Answer 109

a) 1+2+3

Question 110

Which of the following enzymes catalyzes the synthesis of
fructose-2,6-bisphosphate, appearing as the strongest
activator of the regulatory enzyme of glycolysis:

a) Hexokinase
b) Phosphofructokinase 2
c) Phosphoglycerate kinase
d) Phosphofructokinase 1

Answer 110

b) Phosphofructokinase 2

Question 111

Which of the following metabolic pathways of glucose supplies
reducing equivalents for the synthesis of fatty acids, cholesterol and
other reductive processes.

a) Glycolysis
b) Gluconeogenesis
c) Pentose phosphate pathway
d) Oxidative decarboxylation of pyruvate

Answer 111

c) Pentose phosphate pathway

Question 112

Which of the following hormones has an effect on the liver cells,
resulting in the formation of active dephosphorylated kinase form of
the enzyme phosphofructokinase 2:

a) Glucagon
b) Adrenaline
c) Insulin
d) None of the mentioned above

Answer 112

c) Insulin

Question 113

Which of the following enzymes of the glycolytic pathway catalyzes the
step, which is a oxidative phosphorylation at the substrate level, ie
carries out the synthesis of ATP when a metabolite is oxidized:

a) Phosphofructokinase 1
b) Hexokinase
c) Pyruvate kinase
d) Phosphoglucomutase

Answer 113

c) Pyruvate kinase

Question 114

Which of the listed deficiencies (of enzymes and/or vitamins) lead to
lactic acidosis?

1) thiamine
2) erythrocyte enzymes of glycolysis
3) enzymes of pyruvate dehydrogenase complex
4) muscle enzymes of glycolysis
a) 1+2+3
b) 1+3
c) 2+4
d) All of the mentioned above

Answer 114

d) All of the mentioned above

Question 115

Which of the following statements about the pentose
phosphate pathway of glucose is wrong:

a) It is performed actively in skeletal muscle
b) Supplies NADPH for fatty acid, cholesterol
biosynthesis etc..
c) The acyl-CoA derivatives inhibit the regulatory
enzyme
d) In the first (oxidation) step of the process 2
molecules NADPH are obtained

Answer 115

c) The acyl-CoA derivatives inhibit the regulatory

Question 116

The risk of hemolytic anemia is associated with the deficiency of one of
the following enzymes of the pentose-phosphate pathway. Which is
that enzyme?

a) Transketolase
b) Phosphogluconolaktonase
c) Glucose-6-phosphate dehydrogenase
d) Transaldolase

Answer 116

c) Glucose-6-phosphate dehydrogenase

Question 117

Which of the following enzymes of the glycolytic pathway is regulated
by a covalent modification:

a) Pyruvate kinase
b) Phosphofructokinase 1
c) Aldolase
d) Phosphoglucomutase

Answer 117

a) Pyruvate kinase

Question 118

The failure of which of these enzymes involved in the catabolism of
fructose results into the hereditary disease “congenital fructose
intolerance”:

a) Fructokinase
b) Aldolase B
c) Ttriosokinase
d) none of the above mentioned

Answer 118

b) Aldolase B

Question 119

Which of the following enzymes of gluconeogenesis does not use
energy of ATP, but of GTP.

a) pyruvate carboxylase
b) phosphoglycerate kinase
c) glucose-6-phosphatase
d) phosphoenolpyruvate-carboxykinase (PEPKK)

Answer 119

d) phosphoenolpyruvate-carboxykinase (PEPKK)

Question 120

Which of the following co-enzymes serve as such of the enzyme of the
pentose phosphate pathway, transketolase, and by measuring the
enzymatic activity of transketolase is diagnosed a possible deficiency of
this vitamin in the body:

a) pyridoxal phosphate
b) thiamine pyrophosphate
c) NADP
d) FAD

Answer 120

b) thiamine pyrophosphate

Question 121

In which of the following types of cells the transport of glucose is
insulin-independent:

1) adipocytes
2) brain
3) skeletal muscle cells
4) erythrocytes
a) 1+2+3
b) 1+3
c) 2+4
d) None of the above mentioned

Answer 121

c) 2+4

Question 122

Which of the following statements about the pentose phosphate
pathway in mature erythrocytes is true:

a) Provides ribose-5-phosphate for the synthesis of nucleotides
b) Provides NADPH for fatty acid synthesis
c) Provides NADPH for maintaining the level of reduced glutathione, necessary for the disposal of Н2О2
d) Provides NADPH of cholesterol synthesis

Answer 122

c) Provides NADPH for maintaining the level of reduced glutathione, necessary
for the disposal of Н2О2

Question 123

Which of the following metabolites serve as substrates for the synthesis
of glucose in the gluconeogenesis:

1) pyruvate
2) oxaloacetate
3) glycerol
4) acetyl-CoA
a) 1+2+3
b) 1+3
c) 2+4
d) All of the above mentioned

Answer 123

a) 1+2+3

Question 124

Which of the following statements about the transport of glucose from
the blood into the cells of skeletal muscle is wrong:

a) the transport is carried out by a glucose transporter (facilitated diffusion)
b) insulin stimulates glucose transport through the export of glucose carriers
on the cell membrane, i.e. by increasing the number of transporters on the
cell membrane
c) the glucose enters the cells of the skeletal muscle along the concentration
gradient
d) Insulin induces the biosynthesis of an enzyme which catalyzes
phosphorylation of the free glucose to glucose-6-phosphate

Answer 124

c) the glucose enters the cells of the skeletal muscle along the concentration
gradient

Question 125

Which of the following enzymes involved in gluconeogenesis, is the
most important regulatory enzyme in the process, subjected to
allosteric regulation of variety of modulators:

a) pyruvate carboxylase
b) glucose-6-phosphatase
c) fructose-1,6-bisphosphatase
d) phosphoenolpyruvate-carboxykinase (PEPKK)

Answer 125

c) fructose-1,6-bisphosphatase

Question 126

Which of the following hormones stimulates the gluconeogenesis by
inducing biosynthesis of phosphoenolpyruvate-carboxykinase (PEPKK)
and other specific enzymes of gluconeogenesis:

a) Cortisol
b) Insulin
c) Aldosterone
d) Adenocorticotropic hormone (ACTH)

Answer 126

a) Cortisol

Question 127

Which of the following metabolites of the citrate cycle can be directly
converted to phosphoenolpyruvate, and thus be incorporated into the
gluconeogenesis:

a) Citrate
b) Oxaloacetate
c) α– -Ketoglutarate
d) Fumarate

Answer 127

b) Oxaloacetate

Question 128

Which of the following enzymes involved in the catabolism of galactose

catalyze the metabolic step of the conversion of galactose to galactose-
1-phosphate

a) Galactose-1-phosphate uridyltransferase
b) UDF- galactose-4-epimerase
c) Galactokinase
d) Phosphoglucomutase

Answer 128

c) Galactokinase

Question 129

Which of the following enzymes functioning in gluconeogenesis, is
allosterically activated by Acetyl-CoA:

a) Glucose-6-phosphatase
b) Fructose-1,6-bisphosphatase
c) Phosphoenolpyruvate-carboxykinase (PEPKK)
d) Pyruvate carboxylase

Answer 129

d) Pyruvate carboxylase

Question 130

Which of the activated forms of glucose is used as a direct substrate for
the synthesis of glycogen:

a) Glucose-6-phosphate
b) Glucose-1-phosphate
c) UDP-glucose
d) None of the above mentioned

Answer 130

c) UDP-glucose

Question 131

Which of these metabolites is the allosteric activator of phosphorylated
glycogen synthase b:

a) АTP
b) АМP
c) glucose-6-phosphate
d) fructose-2,6-bisphosphate

Answer 131

c) glucose-6-phosphate

Question 132

Which of the following statements about the metabolism of liver
glycogen is true:

a) During its degradation lactate is released in the blood
b) Glucagon stimulates its synthesis
c) It is broken down during the periods of fasting
d) adrenaline stimulates its synthesis

Answer 132

c) It is broken down during the periods of fasting

Question 133

Glycerol is a non-carbohydrate precursor for the synthesis of glucose in
gluconeogenesis. To which of the listed metabolites of gluconeogenesis
turns the glycerol to:

a) Pyruvate
b) Dihydroxyacetone phosphate
c) Phosphonenolpyruvate
d) Fructose-6-phosphate

Answer 133

b) Dihydroxyacetone phosphate

Question 134

Which of the following metabolic steps of gluconeogenesis is common
for glycolysis and gluconeogenesis:

a) fructose-6-phosphate → Glucose-6-phosphate
b) pyruvate →oxaloacetate
c) fructose-1,6-bisphosphate → fructose-6-phosphate
d) oxaloacetate → phosphonenolpyruvate

Answer 134

b) pyruvate →oxaloacetate

Question 135

In which of the following organs the gluconeogenesis is performed:

1) liver
2) small intestine
3) renal cortex
4) skeletal muscles
a) 1+2+3
b) 1+3
c) 2+4
d) All of the above mentioned

Answer 135

b) 1+3

Question 136

Alcohol (ethanol) inhibits the gluconeogenesis. Which of the following
statements about the inhibitory effect of ethanol is wrong:

a) oxidation of the ethanol leads to an increased level of NAD.H in hepatocytes
b) the high levels of NAD.H direct the lactate dehydrogenase reaction to the
conversion of pyruvate to lactate, which lowers the concentration of
pyruvate as a precursor of gluconeogenesis.
c) ethanol itself serves as inhibitor of the enzymes involved in
gluconeogenesis.
d) ethanol decreases the concentration of other substrates for
gluconeogenesis, in pyruvate (e.g., oxaloacetate)

Answer 136

d) ethanol decreases the concentration of other substrates for
gluconeogenesis, in pyruvate (e.g., oxaloacetate)

Question 137

Which of the following statements about the effects of cortisol on the
blood glucose level is correct:

a) cortisol increases blood glucose level by stimulating the glycogenolysis
b) cortisol increases blood glucose level by stimulating gluconeogenesis
c) cortisol decreases blood glucose level by increasing the uptake of glucose
into cells
d) cortisol decreases blood glucose level by stimulating the glycolysis

Answer 137

b) cortisol increases blood glucose level by stimulating gluconeogenesis

Question 138

Which of the following enzymes involved in glycogen metabolism,
catalyzes the phosphorolytic breakdown of α-1,4-glycosidic bond:

a) glycogen synthase
b) glycogen phosphorylase
c) phosphoglucomutase
d) amylo-1,4 → 1,6-transglycosylase

Answer 138

b) glycogen phosphorylase

Question 139

Which of the following statements about the metabolism of liver
glycogen is wrong:

a) it is synthesized after carbohydrate-rich food intake
b) insulin stimulates its synthesis
c) it is broken down in conditions with high blood glucose levels
d) by degradation it provides blood glucose

Answer 139

c) it is broken down in conditions with high blood glucose levels

Question 140

Which of the following statements about the influence of insulin on
blood glucose level is wrong:

a) Insulin reduces the level of blood glucose by accelerating its transport from
the blood into insulin-dependent tissues
b) Insulin stimulates the synthesis of liver and muscle glycogen
c) Insulin does not stimulate glucose transport in adipose tissue
d) Insulin stimulates glycolysis in the liver

Answer 140

c) Insulin does not stimulate glucose transport in adipose tissue

Question 141

Which of the following enzymes is not present in the
muscles that could explain the fact that skeletal muscles
do not release blood glucose after the breakdown of
glycogen:
a) kinase of phosphorylase
b) phosphoglucomutase
c) glucose-6-phosphatase
d) glycogen phosphorylase

Answer 141

c) glucose-6-phosphatase

Question 142

The following enzymes and hormones are involved in the cascade of
events leading to degradation of muscle glycogen under stress. Indicate
which of them does not participate:

a) Adrenaline
b) Adenylyl cyclase
c) Protein kinase A
d) Glucagon

Answer 142

a) Adrenaline

Question 143

Which of the following hormones is a major regulator of blood glucose
level after meals:

a) glucagon
b) insulin
c) adrenaline
d) cortisol

Answer 143

b) insulin

Question 144

Which of the following symptoms is not typical for patients with
diabetes:

a) glucosuria
b) ketoacidosis
c) hypoglycemia
d) polyuria

Answer 144

d) polyuria

Question 145

The breakdown of liver glycogen is stimulated by glucagon via one of
the listed below secondary cell messengers. Which is that messenger?

a) calcium ions
b) cAMP
c) diacylglycerol
d) inositol-triphosphate

Answer 145

b) cAMP

Question 146

Which of the following statements about the mechanism by which insulin
affects the activity of glycogen synthase (regulatory enzyme of
glycogenogenesis) is wrong:

a) insulin decreases the level of cAMP, which leads to dropout of the activation of Protein kinase A, catalyzing the formation of the active phosphorylated form of the protein, called “inhibitor-1”
b) When the inhibitory protein-1 is inactive (dephosphorylated) it does not inhibit the
activity of proteinphosphstase – 1
c) the active protein phosphatase-1 catalyzes the dephosphorylation of glycogen
synthase (glycogen synthase a)
d) insulin signaling leads to creating of the phosphorylated form of glycogen synthase
(glycogen synthase b)

Answer 146

a) insulin decreases the level of cAMP, which leads to dropout of the activation of Protein kinase A, catalyzing the formation of the active phosphorylated form of the protein, called “inhibitor-1”

Question 147

Which of the following amino acids contains a hydroxyl group in its side
chain:

1) methionine
2) threonine
3) valine
4) serine

a) 1+2+3
b) 1+3
c) 2+4
d) 4

Answer 147

c) 2+4

Question 148

Which of the following amino acids contains an aromatic ring in its side
chain:

1) isoleucine
2) proline
3) serine
4) tyrosine
a) 1+2+3
b) 1+3
c) 2+4
d) 4

Answer 148

d) 4

Question 149

• What is the electric charge of an amino acid in its isoelectric point:
  a)positive
  *b) zero
  *c) negative
  *d) -2

Answer 149

*b) zero

Question 150

• Which of the following amino acid residues in the protein molecules
  may participate in the formation of
• ionic bonds:
  1) glutamate
• 2) histidine
  3) arginine
  4) asparagine
• a) 1+2+3
• b) 1+3
  c) 2+4
  d) 1+2+3+4

Answer 150

a) 1+2+3

Question 151

• Which of the following values of the pH corresponds to the isoelectric
  point of the amino acid alanine, keeping in mind that pKa1 of the
  COOH group is 2.35 and pKa2 of the NH2 group is 9.69:
• a) 4.8
  b) 7.24
  c) 6.02
  d) 3.0

Answer 151

c) 6.02

Question 152

Which of the following amino acids has branched side chain:
* a) isoleucine
* b) tyrosine
c) serine
d) proline

Answer 152

a) isoleucine

Question 153

• Which of the following amino acids is basic:
  a) glutamate
• b) arginine
• c) methionine
• d) alanine

Answer 153

b) arginine

Question 154

Which of the following amino acids are essential:
* 1) valine
2) lysine
3) threonine
4) phenylalanine
* a) 1+2+3 b) 1+3
* c) 2+4
* d) 1+2+3+4

Answer 154

• d) 1+2+3+4

Question 155

Which chemical bonds participating in the building of protein
molecules are covalent:
* a) hydrogen
b) ionic
c) hydrophobic interactions
d) disulphide bond

Answer 155

d) disulphide bond

Question 156

Which of the following biologically active peptides is / are tissue
hormone/s of gastrointestinal tract:
* 1) vasopressin
* 2) cholecystokinin
* 3) angiotensin
4) gastrin
* a) 1+2+3
* b) 1+3
c) 2+4
* d) 4

Answer 156

c) 2+4

Question 157

Select the biologically active peptide which acts as a protector against
the harmful effect of reactive oxygen species (ROS):
* a) endorphin
* b) glutathione
* c) enkephalin
* d) melanocyte-stimulating hormone

Answer 157

b) glutathione

Question 158

Which of the following amino acids is sulfur-containing:

a) isoleucine
b) tyrosine
c) serine
d) methionine

Answer 158

d) methionine

Question 159

Which of the following biologically active peptides is
neuropeptide that binds to opioid receptors in the brain and appears
to be one of the natural pain relieving substances:
* a) endorphine
* b) glutathione
* c) neuropeptide Y
* d) melanocyte-stimulating hormone

Answer 159

a) endorphine

Question 160

Which of the following statements about biologically active peptide
glutathione is wrong:
a) all peptide bonds in the glutathione are formed between –COOH
group bound to α-C atom of one of the amino acid and the -NH2
group of the next amino acid
* b) glutathione is a tripeptide
* c) sulfhydryl group of the cysteine residue has a major role in the
function of glutathione
* d) glutathione consists of glutamic acid, cysteine and glycine

Answer 160

a) all peptide bonds in the glutathione are formed between –COOH

Question 161

Whichof the following biologically active peptides is a hormone with
powerful vasoconstrictor effect and is involved in the regulation of Na
ions in the body:
* a) cholecystokinin
* b) bradykinin
* c) melanocyte-stimulating hormone
* d) angiotensin II

Answer 161

d) angiotensin II

Question 162

Select the chemical bonds involved in the formation of the secondary
structure of the protein molecules “β-sheet”:

• a) intrachain and / or interchain hydrogen bonds between amino acid side radicals
• b) intrachain and / or interchain hydrogen bonds between groups of the peptide bonds
• c) ionic bond
• d) disulphide bonds

Answer 162

• b) intrachain and / or interchain hydrogen bonds between groups of the peptide bonds

Question 163

• Which of the following proteins do not belong to the group of
  metalloproteins:
• a) transferrin
• b) transcortin
• c) ferritin
• d) ceruloplasmin

Answer 163

• b) transcortin

Question 164

Which of the following plasma proteins does not perform transport function:

• 1) α1-fetoprotein
• 2) hemopexin
• 3) C-reactive protein
• 4) ceruloploasmin
  a) 1+2+3
• b) 1+3
• c) 2+4
• d) 4

Answer 164

• b) 1+3

Question 165

• Which of the following proteins is not structural:
• a) casein
• b) keratin
• c) fibrillin
• d) elastin

Answer 165

• a) casein

Question 166

Select the chemical bonds involved in the formation of the
secondary structure of the protein molecules “α-helix”:

a) interchain hydrogen bonds between amino acid side
radicals
b) ionic bonds
c) interchain hydrogen bonds between groups of the
peptide bonds
d) disulfide bridge

Answer 166

a) interchain hydrogen bonds between amino acid side
radicals

Question 167

• Which of the following proteins are not complex (proteides):

a) Lipoproteins
b) Albumin
c) Nucleoproteins
d) Hemoproteins

Answer 167

b) Albumin

Question 168

• Which is the non-protein component of the complex protein, casein:

a) Porphyrin structure
b) Phophoric acid
c) Nucleic acid
d) Lipid structure

Answer 168

d) Lipid structure

Question 169

What type of biomolecules are the enzymes by their chemical nature:

• a) nucleoproteins
• b) lipoproteins
  c) glycolipids
  d) proteins

Answer 169

d) proteins

Question 170

Which of the following statements about enzymes is wrong:

a) enzymes are biocatalysts
b) accelerate only thermodynamically possible reactions
c) withdraw the balance of the chemical reaction to produce
more product compared to the uncatalyzed reaction
d) they cause a decrease in the energy barrier of the chemical
reaction

Answer 170

d) they cause a decrease in the energy barrier of the chemical
reaction

Question 171

Which of the compounds listed below is/are not cofactor/s of oxidoreductases?
1) NAD+
2)FAD*
3)lipoate
4)pyridoxal phosphate

a) 1+2+3

b) 1+3

c)2+4

d) 4

Answer 171

d) 4

Question 172

Which of the following statements about the role of the metal ions in the enzymatic catalysis are true:
1) connecting with the apoenzyme they can stabilize the conformation of the active site
2)some of them participate in the electron transfer

3)by forming a complex with the substrate they can facilitate the binding to the active site
4)do not act as catalytic groups in the active site

a)1+2+3

b)1+3

c)2+4

d)1+2+3+4

Answer 172


a)1+2+3


Question 173

What is the specific name of the enzymes which catalyze the transfer
of phosphate groups from ATP on substrates:

• a) kinases
• b) phosphatases
  c) oxidases
  d) dehydrogenases

Answer 173

• a) kinases

Question 174

To which of the following classes of the enzymes belong peptidases?
* a) hydrolases
* b) transferases
c) oxido-reductases
* d) isomerases

Answer 174

a) hydrolases

Question 175

To which of the following classes of the enzymes belong
carboxylases?

a) hydrolases
b) ligases
c) Isomerases
d) Oxido-reductases

Answer 175

b) ligases

Question 176

Which of the following statements about isoenzymes is wrong?
a)the isoenzyme forms of an enzyme are found in all individuals of the human population
b)the isoenzymes of a particular enzyme are localized in different subcellular structures, organs and tissues of one organism
C)the isoenzymes catalyze different chemical reactions
d)the isoenzymes differ in their physicochemical characteristics

Answer 176

C)the isoenzymes catalyze different chemical reactions

Question 177

which type of reversible inhibitors of the enzymes may be referred antimetabolites:
a)competitive
b)non-competitive
c)uncompetitive
d)allosteric

Answer 177

a)competitive

Question 178

Which of the following statements about the substances modulating the catalytic activity of allosteric enzymes is wrong:

a)modulators might be metabolites of the pathway in which acts the allosteric enzyme or metabolites of other metabolic pathways

b)the final product of the pathway that results in excessive concentrations is often an inhibitor of the regulatory allosteric enzyme of the same pathway

c)the action of the metabolites as modulators depends on their concentration in the cell

d)when the substrate of the metabolic pathway is in excess it always acts as an activator of the allosteric regulatory enzyme in the same pathway

Answer 178

d)when the substrate of the metabolic pathway is in excess it always acts as an activator of the allosteric regulatory enzyme in the same pathway

Question 179

Which of the following effects on the enzymes is considered to be irreversible inhibition:
1. permanent binding and blocking of the functional group in the active site
2. destroying the native structure of the enzyme under the action of chemical agents
3. permanent binding and blocking the enzyme cofactor
4. binding with the active center by structural analogy with the substrate
a) 1+2+3
b) 1+3
c)2+4
d)1+2+3+4

Answer 179

b) 1+3

Question 180

Which of the following statements about the impact of the catalytic activity of regulatory enzymes by covalent modification (phosphorylation / dephosphorylation) is wrong:
a) phosphorylation represents binding by covalent bond of the phosphate group, donor of which is ATP, to a specific functional group of an amino acid residue of the apoenzyme
b)the functional group which binds the phosphate group from ATP is an amino group, not involved in the formation of the peptide bond
c) phosphorylation is catalyzed by protein kinases
d)in dephosphorylation which is catalyzed by protein phosphatases, the covalent bond between the phosphate group and a functional group of apoenzyme is hydrolyzed while giving inorganic phosphate

Answer 180

b)the functional group which binds the phosphate group from ATP is an amino group, not involved in the formation of the peptide bond

Question 181

Which of the following statements about alloenzymes is wrong:
a) many of the enzymes have alloenzyme forms
b)alloenzymes are encoded by different alleles of the same gene
c)most of the alloenzymes differ by one or several amino acid residues
d)each individual of the human population has several forms of a alloenzymes of an enzyme

Answer 181

d)each individual of the human population has several forms of a alloenzymes of an enzyme

Question 182

Bearing in mind that organophosphate compounds (e.g. the chemical weapons - sarin, soman, tabun) are irreversible inhibitors of enzymes, indicate which of the following amino acid functional groups in the active site of the enzymes are blocked by covalent bonds by those enzyme toxins:
a)carboxyl group of glutamate
b)ammo group of lyrine
c)hydroxyl group of serine
d)sulfhydryl group of cysteine

Answer 182

c)hydroxyl group of serine

Question 183

Which of the enzymes are studied in the diagnosis of liver diseases (e.g. viral hepatitis, obstructive jaundice etc)
1. Acidic phosphatase
2. AsAT (GOT)
3. Creatine kinase
4) ALAT (GPT)

a) 1+2+3

b) 1+3

c) 2+4

d) 1+2+3+4

Answer 183


c) 2+4

Question 184

Tetrahydrofolate is a co-factor of transferases which catalyze the transfer of some of the listed below functional groups. Which are those groups?
a)one-carbon groups
b)amino groups
c)phosphate groups
d)reducing equivalints (H2)

Answer 184

a)one-carbon groups

Question 185

Which of the enzymes are studied in the diagnosis of myocardial infarction:
1. AsAT (GOT) - aspartate aminotransferase
2. LDH - lactate dehydrogenase
3. CK - creatine kinase
4)HBDH - alpha-hydroxybutyrate dehydrogenase
a) 1+2+3
b)1+3
c)2+4
d) 1+2+3+4

Answer 185

d) 1+2+3+4

Question 186

Which of the following statements about allosteric enzymes is wrong?
A)generally they are oligomeric proteins, i.e. they have quaternary structure
b) the substrate is always allosteric activator
c)contain one or more allosteric sites which bind the modulator/modulators
d)the binding of the modulator is reversible

Answer 186

b) the substrate is always allosteric activator

Question 187

Enzymes of which group catalyse synthetic
reactions requiring energy most often supplied by
ATP:

a) Ligases
b)Oxido-reductase
c) Isomerases
d)lyases

Answer 187

a) Ligases

Question 188

Which of the following diseases, caused by enzyme deficiency, are deposition
diseases?

1) glycogenosis
2) tyrosinosis 3) sphingolipidoses
4) porphyrias
a) 1+2+3
b) 1+3
c) 2+4
d) 1+2+3+4

Answer 188

b) 1+3

Question 189

The symptoms of which of the following enzymopathies are due to
acceleration of the minor pathways of the substrates of the main
metabolic pathway having enzyme deficiency:

a) fructosuria
b) gout
c) phenylketonuria
d) porphyria

Answer 189

b) gout

Question 190

The deficiency of which of the following vitamins causes the disease
“beriberi”?

• a) folic acid
• b) thiamine
• c) biotin
• d) ascorbic acid

Answer 190

b) thiamine

Question 191

The deficiency of which of the following vitamins causes the disease
scurvy?

1. ascorbic acid
2. thiamine
3. Biotin
4. niacin

Answer 191

1. ascorbic acid

Question 192

Which of the following vitamins is not water soluble:
a) Riboflavin
b) Cholecalciferol
c) Biotin
d) Niacin

Answer 192

b) Cholecalciferol

Question 193

Which of the following statements about vitamin b6 is wrong:

a) It exist in three natural derivatives: pyroxine (ol), pyridoxal,
pyridoxamine.
b) Biologically active are two of the phosophates of the two forms, as
pyridoxalphosphate is main co-factor form.
c) Pyridoxalphosphate is cofactor only of transaminases
d) Pyridoxalphophate stabilizes and is required for activation of muscle
glycogen phosphorylase

Answer 193

c) Pyridoxalphosphate is cofactor only of transaminases

Question 194

Which of the following enzyme groups biotin (vitamin h.) is a prosthetic
group?

a) Transaminases
b) Dehydrogenases
c) Decarboxylases
d) carboxylases

Answer 194

b) Dehydrogenases

Question 195

Which of the following types of lipids is not a component of the
membrane structures:

• a) cholesterol
• b) triacylglycerols
  c) cardiolipins
  d) phosphatidylethanolamine

Answer 195

b) triacylglycerols

Question 196

Which of the following lipids are glycolipids:

• 1) sphingomyelins
  2) gangliosides
  3) cephaline
• 4) cerebrosides a) 1+2+3
• b) 1+3
• c) 2+4
• d) none of the above mentioned

Answer 196

• d) none of the above mentioned

Question 197

Which of the following statements about the activation of fatty acids
before their inclusion in β- oxidation is wrong:

• a) activation of fatty acids is by binding their carboxyl group with coenzyme A
  and turning
• them into acyl CoA derivatives
• b) activation of the fatty acids takes place in the mitochondrial matrix
• c) activation of the fatty acids takes place in the endoplasmic reticulum
• d) long chain fatty acids are activated

Answer 197

c) activation of the fatty acids takes place in the endoplasmic reticulum

Question 198

Which of the following pairs of vitamins act as coenzymes in the β-
oxidation of fatty acids with an odd number of carbon atoms:

• a) vit. B1 and folic acid
• b) biotin and vit. B12
• c) folic acid and biotin
• d) vit.В12 and vit.В1

Answer 198

b) biotin and vit. B12

Question 199

• Which of the following shuttle mechanisms is involved in the transfer
  of activated fatty acids from the cytosol into the mitochondria?:
• a) malate-aspartate
• b) glycerol-phosphate
• c) acyl-carnitine
• d) none of the above mentioned

Answer 199

• c) acyl-carnitine

Question 200

Which of the following metabolites is an allosteric inhibitor of the
regulatory enzyme of β- oxidation:

• a) Propionyl-CoA
• b) Malonil-CоА
• c) Butyryl-CoA
• d) none of the above mentioned

Answer 200

• b) Malonil-CоА

Question 201

Which of the following statements about ketone bodies is wrong:

• a) substrate for the synthesis of ketone bodies is acetyl CoA, obtained from
  the oxidative decarboxylation of pyruvate
• b) ketone bodies are acetoacetate, β-hydroxybutyrate and acetone, as
  acetone is product of acetoacetate degradation.
• c) ketone bodies are an energy source alternative of glucose
• d) the concentration of the β-hydroxybutyrate in the blood is usually higher
  than that of the acetoacetate

Answer 201

• d) the concentration of the β-hydroxybutyrate in the blood is usually higher
  than that of the acetoacetate

Question 202

In which of the following organs the synthesis of ketone bodies
(ketogenesis) takes place:

• a) skeletal muscles
• b) brain
• c) kidneys
• d) liver

Answer 202

• d) liver

Question 203

Which of the following hormones stimulates ketogenesis in the
periods of fasting:

• a) insulin
• b) cortisol
• c) glucagon
• d) none of the above mentioned

Answer 203

• c) glucagon

Question 204

• Triacylglycerols from the diet are transported by one of the following
  transport form. Which is that:
• a) chylomicrons
• b) verylow-densitylipoproteins(VLDL)
• c) high-density lipoproteins (HDL)
• d) low-densitylipoproteins(LDL

Answer 204

• a) chylomicrons

Question 205

Which of the following enzymes catalyzes the hydrolysis of
triacylglycerols located in different lipoprotein complexes (e.g. in
chylomicrons, VLDL)

• a) lecithin-cholesterol-acyltransferase
• b) lipoproteinlipase
• c) pancreatic lipase
• d) hormone-sensitive lipase

Answer 205

• b) lipoproteinlipase

Question 206

Which of the following transport forms of lipids contain the so-called,
alpha (α) cholesterol, which usually is determined in clinical
laboratory tests of the blood.
* a) chylomicrons
* b) low-density lipoproteins(LDL)
* c) high-density lipoproteins (HDL)
* d) very low-density lipoproteins(VLDL

Answer 206

• c) high-density lipoproteins (HDL)

Question 207

Which of the following enzymes catalyzes the hydrolysis of
triacylglycerols located in different lipoprotein complexes (e.g. in
chylomicrons, VLDL)

• a) lecithin-cholesterol-acyltransferase
• b) lipoproteinlipase
• c) pancreatic lipase
• d) hormone-sensitive lipase

Answer 207

• b) lipoproteinlipase

Question 208

Which of the following statements for the synthesis of saturated fatty
acids with an even number of carbon atoms (palmitic acid) is false:

• a) direct substrate for the synthesis is malonyl-CoA
• b) NAD.H serves as a donor of reducing equivalents
• c) synthesis takes place in the cytosol
• d) binding of each of the two-carbon fragment in the elongation
  process of the carbon chain of the fatty acid is performed in four
  metabolic step

Answer 208

• d) binding of each of the two-carbon fragment in the elongation
  process of the carbon chain of the fatty acid is performed in four
  metabolic step

Question 209

Which of the following enzymes involved in β-oxidation of fatty
acids with an even number of carbon atoms, is a regulatory enzyme
of the process:

• a) carnitine acyltransferase I (carnitine:palmitoyltransferase I)
• b) acyl CoA dehydrogenase
• c) enoyl CoA hydrogenase
• d) carnitineacyltransferaseII(carnitine:palmitoyltr

Answer 209

• a) carnitine acyltransferase I (carnitine:palmitoyltransferase I)

Question 210

• Which of the following statements about the regulation of the activity
  of the regulatory enzyme of fatty acid biosynthesis, acetyl-CoA
  carboxylase is false:
• a) the activity is regulated by the mechanism of covalent modification
  (phosphorylation / dephosphorylation), аs the active form is phosphorylated.
• b) the activity is influenced by the action of hormones, as insulin stimulates
  the enzymatic activity
• c) the activity is regulated by the mechanism of covalent modification
  (phosphorylation / dephosphorylation), the active form is dephosphorylated.
• d) the activity of the enzyme is regulated allosterica

Answer 210

• c) the activity is regulated by the mechanism of covalent modification
  (phosphorylation / dephosphorylation), the active form is dephosphorylated.

Question 211

Which one of the metabolites of glycolysis occurring in adipocytes, is
converted to glycerol-3- phosphate being one of the substrates for
the synthesis of triacylglycerols in adipose tissue:

• a) glyceraldehyde-3-phosphate
  b) pyruvate
• c) 3-phosphoglycerate
• d) dihydroxyacetonephosphate

Answer 211

• d) dihydroxyacetonephosphate

Question 212

Which of the following enzymes is regulatory in degradation of
triacylglycerols in adipose tissue:

• a) lipoprotein lipase
• b) glycerolkinase
• c) phospholipase
• d) hormone-sensitive lipase

Answer 212

• d) hormone-sensitive lipase

Question 213

Which of the following statements about the degradation of
triacylglycerols in adipose tissue is false:

a)triacylglycerols are degraded when the insulin/glucagon ratio in the blood is high
b)triacylglycerols are degraded during fasting
*c) triacylglycerols are degraded rapidly in patients with diabetes mellitus
* d) triacylglycerols are degraded under elevated level

Answer 213

a)triacylglycerols are degraded when the insulin/glucagon ratio in the blood is high

Question 214

• Which of the following biological functions of cholesterol is not
  correct:
• a) cholesterol participates in the construction of the cell membranes as a
  stabilizing component
• b) cholesterol serves as a precursor for steroid hormone synthesis
• c) cholesterol serves as a precursor for vitamin E synthesis
• d) cholesterol serves as a precursor for bile acids synthesis

Answer 214

• c) cholesterol serves as a precursor for vitamin E synthesis

Question 215

• Which of the following metabolites is obtained in the biosynthesis of
  ketone bodies, and in the biosynthesis of cholesterol in the liver, i.e.,
  appears to be a key metabolite.
• a) mevalonic acid
• b) hydroxy-methylglutaryl-CoA
• c) ß- hydroxybutyrate
• d) isopentenylpyrophosphate

Answer 215

• b) hydroxy-methylglutaryl-CoA

Question 216

Which of the following cofactors supplies reducing equivalents for the
action of the enzyme HMG-CoA reductase:
* a) NAD.H
b) FAD.Н2
c) NADP.Н
* d) FMN.H2

Answer 216

• a) NAD.H

Question 217

Which of the following statements about regulation of cholesterol
biosynthesis is true:

• a) cholesterol synthesis is not affected by the concentration of cholesterol
• b) cholesterol acts as an allosteric activator of the HMG-CoA reductase
• c) cholesterol acts as an allosteric inhibitor of HMG-CoA synthase
• d) cholesterol represses the synthesis of HMG-CoA reductase

Answer 217

• d) cholesterol represses the synthesis of HMG-CoA reductase

Question 218

Which of the following statements about the regulation of enzyme
activity of 7α-hydroxylase which regulates the conversion of
cholesterol to bile acids in the liver is false:

• a) the catalytic activity of 7α-hydroxylase is regulated by phosphorylation /
• dephosphorylation, and the active form of the enzyme is dephosphorylated
• b) cholesterolenhances7α-hydroxylasemRNA
• c) bile acids inhibit the enzyme synthesis
• d) in Vit. C deficiency the metabolic step catalyzed by 7α-hydroxylase slows
  down.

Answer 218

• a) the catalytic activity of 7α-hydroxylase is regulated by phosphorylation /
• dephosphorylation, and the active form of the enzyme is dephosphorylated

Question 219

• Which of the following statements about arachidonic acid is wrong:
  *
• A) arachidonic acid is a polyunsaturated FA containing 20 carbon atoms
• B) arachidonic acid is 3 polyunsaturated fatty acid
• C) arachidonic acid is a precursor for the synthesis of eicosanoids:
  prostaglandins, thromboxanes with 2 double bonds and leukotrienes with 4
  double bonds
• D) arachidonic acid participates in the construction of membrane
  phospholipids

Answer 219

• B) arachidonic acid is 3 polyunsaturated fatty acid

Question 220

Which of the following statements about the physiological functions
of eicosanoids is false:

• a) They participate in inflammatory processes, in injuries and
  infections
• b) Some of the eicosanoids are involved in platelet aggregation
• c) Some regulate smooth muscle contractions (intestine, uterus)
• d) All eicosanoids act as vasoconstrictors

Answer 220

• d) All eicosanoids act as vasoconstrictors

Question 221

• The high concentration of which of the lipid transport forms listed
  below decreases the risk of developing of atherosclerosis and
  coronary heart disease?
• a) HDL
• b) chylomicrons
• c) LDL
  d) VLDL

Answer 221

• a) HDL

Question 222

Which of the listed subcellular compartments is the place, where the
oxidation of fatty acids leading to introduction of double bond is
performed:

• a) mitochondria
• b) lysosomes
• c) endoplasmic reticulum
• d) cytoplasm

Answer 222

• c) endoplasmic reticulum

Question 223

• Eicosatetraenoic acid is a precursor for the synthesis of:
• 1) prostanoids with 2 double bonds
  2) leukotrienes with 3 double bonds
  3) lipoxins with 4 double bonds
• 4) prostanoids with 3 double bonds
• a) 1+2+3
  b) 1+3
  c) 2+4
• d) none

Answer 223

c) 2+4

Question 224

• The oxidative phase of the PPP (pentose phosphate pathway) is important
  for:
• 1) cholesterol synthesis
• 2) synthesis of ATP
  3) fatty acid synthesis
• 4) gluconeogenesis
• a) 1+2+3
• b) 1+3
• c) 2+4
• d) allfour

Answer 224

• c) 2+4

Question 225

• Which of the following mechanisms, for activating of the
  biosynthesis of fatty acids from the insulin is incorrect:
• a) insulin with its signaling cascade leads to the active
  unphosphorylated form of the regulatory enzyme acetyl-CoA
  carboxylase
• b) insulin with its signaling cascade leads to induction of the
  biosynthesis of the regulatory enzyme of fatty acid synthesis - acetyl- CoA carboxylase
• c) insulin with its signaling cascade leads to induction of the
  biosynthesis of the multifunctional enzyme complex, fatty acid synthase
  complex
• d) insulin with its signaling cascade leads to activation of the enzyme
  glycerol-3- phosphate acyl transferase, via maintaining of its
  unphosphorilated form

Answer 225

• d) insulin with its signaling cascade leads to activation of the enzyme
  glycerol-3- phosphate acyl transferase, via maintaining of its
  unphosphorilated form

Question 226

Which of the following compounds are cholesterol derivatives?

1) aldosterone
2) adrenaline
3) cortisol
4) cholicacid
a) 1+2+3
b) 1+3
c) 3+4
d) 1+3+4

Answer 226

a) 1+2+3

Question 227

Which of the following compounds is a key (a key metabolite) in the
synthesis of most glycerolipids?

а) choline
b) CDP-choline
c) phosphatidic acid
d) CDP- diacylglycerol

Answer 227

c) phosphatidic acid

Question 228

Which of the enzymes that catalyze reactions in the synthesis of
glycerolipids is regulatory?

a) phosphatidic acid phosphatase
b) glycerol-3P-acyltransferase
c) diacylglycerol acyltransferase
d) phosphatidylinositol synthase

Answer 228

b) glycerol-3P-acyltransferase

Question 229

Which of the following groups of lipids are glycolipids?

1) sphingomyelins
2) gangliosides
3) cerebrosides
4) lecithins
a) 1+2+3
b) 2+3
c) 1+4
d) 2+3+4

Answer 229

d) 2+3+4

Question 230

Which of the following essential polyunsaturated fatty acids (PUFA) are
supplied only from foods of animal origin.

1) linoleicacid
2) arachidonicacid
3) eicosapentaenoic acid
4) linolenic acid
a) 1+2+3
b) 2+3
c) 1+4
d) 2+3+4

Answer 230

b) 2+3

Question 231

On which positions in the hydrocarbon chains of the fatty acids double
bonds may be introduced in man (desaturases function in human
cells)?

а) 4, 5, 8 and 9
b) 4, 5, 6 and 9
c) 5, 8, 11 and 14
d) 4, 5, 8 and 9

Answer 231

d) 4, 5, 8 and 9

Question 232

Which of the following biological effects are typical for PGE2?

• 1) bronchoconstrictor
• 2) vasodilator
• 3) inhibits the secretion of gastric juice
• 4) inhibits the uterine contractions
• a) 1+2+3
• b) 2+3
  c) 2+4
  d) 2+3+4

Answer 232

c) 2+4

Question 233

• Which of the following reactions and processes provide reducing
  equivalents (NADPH) used in the synthesis of fatty acids?
• 1) anaerobic glycolysis
  2) pentose phosphate pathway
  3) reaction catalyzed by malate dehydrogenase
• 4) reaction catalyzed by “malate” enzyme
• a) 1+2+3
• b) 2+3
  c) 2+4
• d) 2+3+4

Answer 233

c) 2+4

Question 234

• Which of the following compounds is the direct donor of 14 of the 16
  carbon atoms in the synthesis of palmitic acid?
• а) acetyl-CоА
  b) acyl-CоА
  c) malonyl-CоА
  d) methilmalonyl-CоА

Answer 234

c) malonyl-CоА

Question 235

Which of the following compounds are not allosteric activators of the main
key enzyme in the synthesis of fatty acids, Acetyl CoA carboxylase?

1) acyl-CоА
2) acetyl-CоА
3) malonyl-CоА
4) citrate
a) 1+2+3
b) 2+3
c) 2+4
d) 2+3+4

Answer 235

c) 2+4

Question 236

In which of the following organs the synthesis of ketone bodies
(ketogenesis):takes place
a) skeletal muscle
b) brain
c) heart muscle
d) liver

Answer 236

d) liver

Question 237

Which of the following hormones stimulates ketogenesis in periods of
fasting?

a) insulin
b) cortisol
c) ACTH
d) glucagon

Answer 237

d) glucagon

Question 238

Which of the following compounds are ketone bodies with metabolic
importance for tissues:

• 1) acetoacetate
  2) oxaloacetate
  3) β- hydroxybutyrate
• 4) acetone
• a) 1+2+3
• b) 1+3
• c) 2+3
• d) 1+3+4

Answer 238

• a) 1+2+3

Question 239

Which of the following lipoprotein complexes are the main carriers of TAG to
peripheral tissues:

1) Chylomicrons
2) VLDL
3) LDL
4) HDL
a) 1+2+3
b) 1+2
c) 1+3+4
d) 3+4

Answer 239

b) 1+2

Question 240

Which of the following enzymes play an important role in the metabolism
of lipoprotein complexes:

• 1) hepaticlipase
• 2) pancreaticlipase
• 3) lipoprotein lipase
• 4) LCAT (lecithin cholesterol acyltransferase)
• a) 1+2+3
• b) 1+2
• c) 1+3+4
• d) 3+4

Answer 240

• d) 3+4

Question 241

Which of the following lipoprotein complexes transport the “bad”
cholesterol and raising of their levels is a risk factor for
atherosclerosis:

• а) chylomicrons
• b) VLDL
  c) LDL
  d) HDL

Answer 241

c) LDL

Question 242

Which of the following coenzymes serves as a donor of reducing
equivalents in the synthesis of fatty acids in fatty acid synthase
complex?

• a) NAD.Н
• b) FAD.Н2
• c) NADP.Н
• d) FMN.Н2

Answer 242

• c) NADP.Н

Question 243

How many turns (cycles) of the spiral of β-oxidation occur for
oxidation of palmitic acid (Palmitoyl-CoA) to Acetyl-CoA?

• a) 10
• b) 8
• c) 7
• d) 6

Answer 243

• c) 7

Question 244

In which of the following cell compartments of hepatocytes the
ketogenesis occurs?
*
* a) cytosol
* b) mitochondria
* c) endoplasmic reticulum
* d) lysosomes

Answer 244

• b) mitochondria

Question 245

Which of the following metabolites is a product of the
degradation of ketone bodies (ketolysis) in extrahepatic tissues?

• a) malonyl -CоА
• b) acetyl-CоА
• c) succinyl -CоА
• d) propionyl-CoA

Answer 245

• b) acetyl-CоА

Question 246

The catabolic pathways are primarily:
Reductive and endergonic
Endergonic and exergonic
Oxidative and endergonic
Oxidative and reductive
Oxidative and exergonic

Answer 246

Oxidative and exergonic

Question 247

Insulin synthesis: 1) occurs in the β-cells of the Langerhans islands, 2) is initiated at a low blood glucose, 3) occurs in the mitochondria and Golgi apparatus, 4) occurs with the release of C-peptide, 5) it is composed of 3 polypeptide chains connected by 2 disulfide bridges
1 + 4
3 + 5
2 + 5
1 + 2
2 + 3

Answer 247

1 + 4

Question 248

Which of the following enzymes is NOT tested for myocardial infarction?
ALT (GPT)
creatine kinase
lactate dehydrogenase
alpha-hydroxybutyrate dehydrogenase
AST (GOT)

Answer 248

ALT (GPT)

Question 249

Which of the listed statements are correct? 1) pyruvate is the substrate for the synthesis of ketone bodies 2) a significant increase in the concentration of ketone bodies leads to a condition called ketoacidosis 3) ketone bodies are an alternative source of energy for the extrahepatic tissues (muscles, brain) 4) ketone bodies are the main energy source for the liver 5) after activation ketone bodies enter the glycolysis, where they are completely oxidized
3+4
1+3
2+5
2+3
1+5

Answer 249

2+3

Question 250

Which of the enzymes that catalyze reactions in the synthesis of
glycerolipids is regulatory?

a) phosphatidic acid phosphatase
b) glycerol-3P-acyltransferase
c) diacylglycerol acyltransferase
d) phosphatidylinositol synthase

Answer 250

b) glycerol-3P-acyltransferase

Question 251

In the cells, the activated fatty acids are transported through the inner mitochondrial membrane into the matrix with the help of:
carnitine
carnosine
carotene
creatine
xanthine

Answer 251

carnitine

Question 252

Which of the following enzymes is a component of the glycerol phosphate shuttle?
malate dehydrogenase
triose phosphate isomerase
glycerol kinase
glycerol 3-phosphate dehydrogenase
glyceraldehyde 3-phosphate dehydrogenase

Answer 252

glycerol 3-phosphate dehydrogenase

Question 253

Cofactor of galactokinase is:
NADH
NADPH
FMN
ATP
FAD

Answer 253

ATP

Question 254

An example of a functional plasma enzyme is:
creatine kinase
aspartate aminotransferase
α-amylase
lactate dehydrogenase
ceruloplasmin

Answer 254

α-amylase

Question 255

Which are the enzymes that deliver NADPH for the synthesis of fatty acids and cholesterol? 1) α-ketoglutarate dehydrogenase 2) malic enzyme 3) the cytosolic isocitrate dehydrogenase 4) the mitochondrial isocitrate dehydrogenase 5) glucose-6-phosphate dehydrogenase
1+3+4
1+3+5
1+2+3
2+3+4
2+3+5

Answer 255

2+3+5

Question 256

Which of the following are the regulatory enzymes of glycolysis?
1) hexokinase
2) 2) glyceraldehyde 3-phoshate dehydrogenase
3) triose phosphate isomerase
4) phosphofructokinase I
5) pyruvate kinase
2+4+5
1+2+3
1+4+5
2+3+4

Answer 256

1+4+5

Question 257

Which of the listed factors are needed for activation of pancreatic lipase: 1) acidic conditions 2) chloride ions 3) neutral or weak alkaline conditions 4) bile acids and lysolecithins 5) the action of colipase
2+3+5
1+2+5
1+2+3
3+4+5
1+3+4

Answer 257

3+4+5

Question 258

Disulfide bonds in the protein molecules are formed between:
two methionine residues
two cysteine residues
two serine residues
two glutamine residues

Answer 258

two cysteine residues

Question 259

Collagen is characterized by the presence of: 1) hydroxyprolyl and hydroxylysyl amino acid residues 2) hydroxyprolyl, but not hydroxylysyl amino acid residues 3) carbohydrate component 4) a structure called “desmosine” 5) triple-helical structure
2+3+5
1+3+4
1+3+5
1+2+3
2+3+4

Answer 259

1+3+5

Question 260

Which of following statements are true?
1) Macroergic compounds are a link between exergonic and endergonic processes
2) ATP contains three macroergic bonds
3) ATP contains two macroergic bonds
4) ADP contains two macroergic bonds 5) AMP contains only one macroergic bond
1+2
2+5
1+5
1+3
1+4

Answer 260

1+3

Question 261

Sphingosine is a precursor of: 1) lecithins 2) phosphatidylinositols 3) cerebrosides 4) gangliosides 5) sphingomyelins
1+3+5
3+4+5
1+3+4
2+4+5
1+2+5

Answer 261

3+4+5

Question 262

Which of the following proteins is an iron-storing protein?
hephaestin
hemosiderin
transferrin
ferritin
ceruloplasmin

Answer 262

ferritin

Question 263

Which of the following statements regarding the β-oxidation of fatty acids with an even number of C-atoms are correct?
1) the oxidation of fatty acids is a mitochondrial process
2)the oxidation of fatty acids is an anaerobic process
3)the end products are Acetyl-CoA, malonyl-CoA, NADH and FADH2
4) the end products are Acetyl-CoA, propionyl-CoA, NADH and FADH2
5) the end products are Acetyl-CoA, NADH and FADH2
1+5
2+5
2+4
3+4
1+3

Answer 263

1+5

Question 264

Which of the listed molecules are oxidized in the Krebs cycle? 1) non-essential amino acids (the carbon skeleton) 2) ketone bodies 3) acetyl-CoA derived from the pyruvate dehydrogenase complex 4) propionyl-CoA obtained by the degradation of fatty acids with an odd number of carbon atoms 5) the final products of the β-oxidation
2+4+5
all of them
1+3+4
1+3+5
2+3+5

Answer 264

1+3+5

Question 265

Which of the following enzymes are expressed only in the liver? 1) urease 2) 3-hydroxy-3-methyl-glutaryl-CoA reductase 3) carbamoyl phosphate synthetase I 4) pyruvate carboxylase 5) bilirubin UDP-glucuronyl transferase activity
4+5
2+4
3+5
1+3
1+5

Answer 265

4+5

Question 266

Protein denaturation leads to: 1) Changes of amino acid composition of the protein molecule 2) Destroying primary structure of the protein molecule 3) Loss the biological activity of the protein 4) Increasing the chemical reactivity of the polypeptide chain of the protein 5) Destroying the secondary, tertiary and quaternary structure
2+3+4
2+3+5
3+4+5
1+3+4
1+2+3

Answer 266

3+4+5

Question 267

The process of heat production depends on:
1) the activity of mitochondrial respiratory chains when the electron transport and phosphorylation are uncoupled
2) the short electron transport chains localized in the endoplasmic reticulum
3) the activity of lysosomal short electron transport chains
4) ion channels in the inner mitochondrial membrane when open
5) ion channels in the inner and outer mitochondrial membranes when open
1+5
2+3
3+5
2+5
1+4

Answer 267

1+4

Question 268

Carbamoyl phosphate synthetase I, which catalyses the formation of carbamoyl phosphate in the urea cycle: 1) is located in the mitochondria of hepatocytes 2) is located in the cytoplasm of hepatocytes 3) is a regulatory enzyme 4) is allosterically activated by N-acetylglutamate 5) is allosterically activated by N-acetylglutamine
2+3+5
3+4+5
2+3+4
1+3+5
1+3+4

Answer 268

1+3+5

Question 269

Antithrombin III: 1) participates in fibrinolysis 2) inhibits the activity of enzymes of the blood clotting process 3) is activated by urokinase 4) works in a complex with the tissue factor (factor III) 5) is activated by heparin
2+4
3+4
2+5
4+5
1+3

Answer 269

2+5

Question 270

Which of the following enzymes catalyse reactions from pentose phosphate pathway?
phospho hexose isomerase
2) glucose 6-phosphate dehydrogenase
3) transaldolase
4) transketolase
5) hexokinase
1+3+4
2+3+5
3+4+5
1+2+5
2+3+4

Answer 270

2+3+4

Question 271

Which of the following enzymes of purine biosynthesis are allosterically regulated? 1) phosphoribosyl pyrophosphate (PRPP) synthetase 2) formyl transferase 3) glutamine-PRPP amidotransferase 4) adenylosuccinase 5) xanthine oxidase
3+4
2+5
1+3
2+4
1+5

Answer 271

1+5

Question 272

Hemorrhages in the joints and subcutaneous tissue, formation of ulcers that are difficult to heal, softening of the gums, anemia are clinical signs of the disease:
pellagra
pernicious anemia
scurvy
beriberi
gout

Answer 272

scurvy

Question 273

Which of the following enzymes catalyze the irreversible steps in gluconeogenesis? 1) aldolase 2) glucose 6-phosphatase 3) fructose 1,6-bisphosphatase 4) pyruvate kinase 5) pyruvate carboxylase
2+3+4
1+2+3
2+3+5
3+4+5
1+3+5

Answer 273

2+3+5

Question 274

The role of free fatty acids in the process of heat production in brown adipose tissue is: 1) isolating the internal organs of the low temperature of the environment 2) when oxidized, they supply hydrogen to the respiratory chain 3) synthesis of triacylglycerols 4) synthesis of ketone bodies 5) activate the uncoupling protein 1.
1+2
3+5
2+4
1+3
2+5

Answer 274

2+5

Question 275

How many are the ATP molecules synthesized by the short electron transport chains during the process of microsomal oxidation?
no ATP molecules
two ATP molecules
one ATP molecule
three ATP molecules
four ATP molecules

Answer 275

two ATP molecules

Question 276

In transamination: 1) amino acids are converted to biogenic amines 2) one amino acid is converted to a keto acid and another keto acid is converted to the corresponding amino acid 3) the amino groups of amino acids are released as free ammonia 4) pyridoxal phosphate participates as a cofactor 5) tetrahydrobiopterin participates as a cofactor
2+5
1+3
2+4
3+4
1+5

Answer 276

2+4

Question 277

In which part of the cell does the pentose phosphate pathway takes place?
the cytosol
the cytosol and matrix of the mitochondria
the inner membrane of the mitochondria
the mitochondrial matrix
peroxisomes

Answer 277

the cytosol

Question 278

Cori’s cycle is about:
synthesis of glutamine in the brain and its deamination in the liver
synthesis of urea in the liver and its excretion with urine
binding of aspartate to a metabolite and further cleavage of its carbon skeleton in the form of fumarate
formation of alanine from pyruvate in the muscles and formation of glucose from alanine in the liver
formation of lactate from glucose in the skeletal muscles and formation of glucose from lactate in the liver

Answer 278

formation of lactate from glucose in the skeletal muscles and formation of glucose from lactate in the live

Question 279

Which of the following hormones are recognized and bound by intracellular receptors? 1) retinoic acid 2) triiodothyronine (T3) 3) TSH 4) calcitriol 5) serotonin
2+3+4
1+3+5
1+2+4
1+2+3
2+3+5

Answer 279

1+2+4

Question 280

Which of the listed enzymes is an enzyme complex of the respiratory chain which does NOT pump protons into the intermembrane space?
Cyt.C: oxygen oxidoreductase
Cytochrome reductase
Succinate dehydrogenase
NAD.H: ubiquinone oxidoreductase
Isocitrate dehydrogenase

Answer 280

Succinate dehydrogenase

Question 281

Which is the mechanism involved in the regulation of the enzymes of Krebs cycle?
a)allosteric control, exerted by either the substrates or products of the chemical reactions
b)proteolytic “maturation” of the protein structure of the enzymes
c)reversible covalent modifications, caused by hormonal signal cascades
d)with the aid of additional enzymes called dprotein kinases or phosphatases
changes in the intracellular location of the enzymes

Answer 281

a)allosteric control, exerted by either the substrates or products of the chemical reactions

Question 282

Which of the end products of heme degradation are increased in parenchymal jaundice (hepatitis)? 1) urobilinogen in urine 2) bilirubin in the urine 3) indirect serum bilirubin 4) direct serum bilirubin 5) stercobillin in the stool
2+3+4
1+3+4
2+3+5
1+2+3
1+3+5

Answer 282

2+3+4

Question 282

Which of the following reactions are reactions of the covalent modification of regulatory enzymes:
1)acetylation
2) methylation
3) phosphorylation
4) adenylation
5) uridinylation
1+3+5
2+4+5
1+2+3
all of them
1+3+4

Answer 282

1+2+3

Question 283

Which statements about hormone-sensitive lipase are correct? 1) it is activated by insulin 2) the active form is the dephosphorylated 3) it is activated by glucagon 4) the active form is the phosphorylated 5) it hydrolyses monoacylglycerols to form free fatty acids (FFAs) and glycerol
1+5
1+3
1+2
2+4
3+4

Answer 283

1+5

Question 284

Which of the listed compounds are known as ketone bodies? 1) oxaloacetate 2) acetone 3) acetoacetate 4) 3-hydroxybutirate 5) acetoacetyl-CoA
3+4+5
1+3+5
1+2+3
1+2+5
2+3+4

Answer 284

2+3+4

Question 285

Which of following statements about non-competitive inhibitors are true? 1) Inhibitor is not a structural analog of the substrate 2) Inhibitor is a structural analogue of the substrate 3) Binds to groups from the active center of the enzyme 4) Binds to groups outside the active site of the enzyme 5) The inhibitory effect depends only on the concentration of the inhibitor
2+3+4
1+3+4
2+3+5
1+3+5
1+4+5

Answer 285

1+4+5

Question 286

Respiratory chains: 1) are located in the outer mitochondrial membrane 2) are located in the inner mitochondrial membrane 3) are complex structures, assembled from enzymes, non-enzyme proteins and redox-systems (electron carriers) 4) transfer hydrogen from NADH or other substrates to oxygen as a final acceptor 5) could act under both aerobic and anaerobic conditions
1+3+4
2+3+4
1+3+5
1+4+5
2+4+5

Answer 286

2+3+4

Question 287

Which of the following is NOT typical for adipocytes of brown adipose tissue:
a large amount of cytochromes
many mitochondria
rich blood supply
presence of thermogenic uncoupling protein
high ATP synthase activity

Answer 287

high ATP synthase activity

Question 288

Which of the following statements about NAD+ and NADP+ are true? 1) Both cofactors are derivatives of vitamin B1 (thiamine) 2) Both cofactors are derivatives of vitamin B3 (niacin, vitamin PP) 3) Both cofactors are derivatives of vitamin B6 (pyridoxol) 4) NAD+ and NADP+ participate in the processes of biological oxidation as hydrogen carriers 5) NAD+ and NADP+ are mainly cofactors of anaerobic dehydrogenases
1+3+4
3+4+5
2+4+5
2+3+5
1+4+5

Answer 288

2+4+5

Question 289

Choose the correct statements about glycogen metabolism: 1) glycogen is synthesized and stored only in the mitochondrial matrix 2) hepatic glycogen is utilized in the maintaining of blood glucose level between the meals 3) glucose-6-phosphate produced in the muscles passes through the cell membrane along the concentration gradient to the blood 4) hepatocytes of the liver contain the enzyme glucose-6 phosphatase, which releases free glucose 5) muscle glycogen is used only by muscle cells
1+2+3
1+2+5
2+4+5
1+3+4
1+3+5

Answer 289

2+4+5

Question 290

Which of the listed compounds are substrates of gluconeogenesis? 1) lactate 2) acetyl-CoA 3) glycerol 4) alanine, glutamate, aspartate 5) glucose
2+4+5
all of them
2+3+4
1+3+4
1+3+5

Answer 290

1+3+4

Question 291

Glutathione is:
tissue hormone
natural opiate
a natural antioxidant
a steroid compound

Answer 291

a natural antioxidant

Question 292

Which of the following metabolic disorders ARE NOT observed in diabetes type 2?
1) hyperglycemia
2) ketoacidosis
3) hypertriglyceridemia (elevated levels of VLDL)
4) hyperchylomicronemia
5) glucosuria
1+5
3+4
2+4
1+3
2+5

Answer 292

2+4

Question 293

Which of the biosynthetic processes are carried out with the participation of tetrahydrofolic acid derivatives as cofactors: 1) synthesis of purines (С2 and С8 atoms) 2) synthesis of choline from ethanolamine 3) synthesis of methionine from homocysteine 4) synthesis of creatine phosphate 5) synthesis of TMP from dUMP
1+3+5
2+3+5
1+2+3
3+4+5
2+3+4

Answer 293

1+3+5

Question 294

Choose the correct statements about the role of glycolysis in the body:
1) delivers reducing equivalents for anabolic pathways
2) supplies acetyl-CoA for the synthesis of ketone bodies
3) supplies substrates for the synthesis of essential amino acids
4) delivers energy to muscle cells during prolonged starvation
5) supplies acetyl-CoA for fatty acid synthesis
2+4+5
1+2+3
1+3
3+5
2+4

Answer 294

2+4

Question 295

cAMP-dependent protein kinase (PKA) phosphorylates: 1) glycogen synthase and inactivates it 2) glycogen synthase and activates it 3) glycogen phosphorylase kinase and activates it 4) glycogen phosphorylase kinase and inactivates it 5) glycogen phosphorylase and activates it
2+5
2+4
1+5
1+3
3+4

Answer 295

1+5

Question 296

Which of the following enzymes are components of the pyruvate dehydrogenase complex (PDH)? 1)acetyl-CoA carboxylase 2) pyruvate dehydrogenase 3) dihydrolipoyl transacetylase 4) dihydrolipoyl dehydrogenase 5) pyruvate kinase
3+4+5
1+3+4
1+2+4
2+4+5
2+3+4

Answer 296

2+3+4

Question 297

The unit of enzyme quantity (activity) in the International System of Units (SI) is Katal. One Katal (Kat) is the amount of the enzyme required to convert:
One mole of substrate for one second
One milimole of substrate per one minute
one milliliter of substrate per one minute
One micromole of substrate per one minute
One micromole of substrate for one second

Answer 297

One mole of substrate for one second

Question 298

Indicate the correct combinations of a neuromediator and the amino acid, form which it is synthesized. 1) gamma-aminobutirate from aspartate 2) gamma-aminobutirate from glutamate 3) serotonin from tryptophan 4) serotonin from tyrosine 5) dopamin from tyrosine
3+4+5
1+3+5
1+2+3
2+3+4
2+3+5

Answer 298

2+3+5

Question 299

Which of the following statements about cholesterol are true? 1) it is synthesized from acetyl-CoA 2) it’s synthesis occurs in the cytosol and in the endoplasmic reticulum 3) the main regulatory enzyme of cholesterol synthesis is HMG-CoA synthase 4) it is fully degraded in the liver 5) it’s synthesis is stimulated by insulin
1+3+4
1+2+5
1+3+5
2+4+5
3+4+5

Answer 299

1+3+5

Question 300

Which of the processes are specific to the liver only? 1) conversion of indirect bilirubin to direct bilirubin, 2) urea cycle, 3) glycogen synthesis, 4) cholesterol synthesis, 5) gluconeogenesis
3 + 5
1 + 2
4 + 5
2 + 3
1 + 4

Answer 300

1 + 2

Question 301

Which statements about thyroid hormones (T4 and T3) are true? 1) inhibit gluconeogenesis and glycogenolysis to prevent the formation of free glucose, 2) T3 is formed only in the thyroid gland, 3) T4 and T3 increase the synthesis and secretion of TSH, 4) T4 and T3 decrease the synthesis and secretion of TSH, 5) the enzyme thyroid peroxidase is involved in their synthesis
2 + 3
1 + 4
3 + 5
1 + 2
4 + 5

Answer 301

4 + 5

Question 302

Which is the WRONG statement?
a)VLDL transports triacylglycerols from the liver to the extrahepatic tissues
b)LDL contains only apo B-100
c) VLDL is metabolized to LDL after hydrolysis of triacylglycerols by hormone-sensitive lipase
d)the main components of LDL are cholesterol and cholesteryl esters
chylomicrons transport mainly triacylglycerols from the intestines to the liver and other tissues

Answer 302

a)VLDL transports triacylglycerols from the liver to the extrahepatic tissues

Question 303

Gout could be caused by:
a)complete deficiency of hypoxanthine/guanine phosphoribosyl transferase
b)a partial deficiency of xanthine oxidase
c)a partial deficiency of hypoxanthine/guanine phosphoribosyl transferase
d)abnormally increased activity of aspartate transcarbamoylase
deficiency of folic aci

Answer 303

complete deficiency of hypoxanthine/guanine phosphoribosyl transferase

Question 304

Which of the listed molecules are signaling molecules?
1) interleukins 2)acetylcholine
3) interferons
4) prostaglandins
5) leukotrienes
c) 2+4+5
d) 1+4+5
b) 1+3+4
all of them
a) 1+2+3

Answer 304

all of them

Question 305

What is the fate of hydrogen released in oxidative reaction in glycolysis? 1) used for the synthesis of fatty acids 2) under anaerobic conditions it is directed for pyruvate reduction 3) under aerobic conditions it is directed for pyruvate reduction 4) under aerobic conditions it is transferred to the matrix of mitochondria 5) directed for the reduction processes in the synthesis of cholesterol
2+4+5
1+3
2+4
3+5
1+2+3

Answer 305

2+4

Question 306

Which of the following symptoms is not typical for patients with diabetes:
hypoglycemia
ketoacidosis
polyuria
glucosuria

Answer 306

hypoglycemia

Question 307

Which of the following enzyme catalyzes the conversion of glucose to glucose-6-phosphate in muscle cells:
Hexokinase
Phosphoglucomutase
Glucose-6-phosphatase
Glucokinase

Answer 307

Glucose-6-phosphatase

Question 308

Which of the following pathways of glucose metabolism is not catabolic:
glycolysis
oxidative decarboxylation of pyruvate
pentose phosphate pathway
gluconeogenesis

Answer 308

gluconeogenesis

Question 309

Which of mentioned biomolecules is the major energetic source for skeletal muscles during their prolonged and medium-intensive activity (long distance running):
glucose
none of them
fatty acids
ketone bodies

Answer 309

ketone bodies

Question 310

Which of the following statements about the mechanism by which insulin affects the activity of glycogen synthase (regulatory enzyme of glycogenogenesis) is wrong:
1. the active protein phosphatase-1 catalyzes the phosphorylation of glycogen synthase (glycogen synthase a)
2.insulin decreases the level of cAMP, which leads to dropout of the activation of protein kinase A, catalyzing the formation of the active phosphorylated form of the protein, called “inhibitor-1”
3.the action of insulin gives the phosphorylated form of glycogen synthase (glycogen synthase b)
4.when the inhibitory protein-1 is inactive (dephosphorylated) it does not inhibit the activity of proteinphosphstase – 1

Answer 310

2.insulin decreases the level of cAMP, which leads to dropout of the activation of protein kinase A, catalyzing the formation of the active phosphorylated form of the protein, called “inhibitor-1”

Question 311

Which of the following alterations does not appear to be a reason for development of Diabetes type II (insulin-independent):
1.decreased affinity of the insulin receptor towards insulin
2.decreased synthesis of insulin receptors
3.synthesis of abnormal (defect) insulin
4.progressive destruction of the B-cells of pancreas by autoimmune mechanisms

Answer 311

4.progressive destruction of the B-cells of pancreas by autoimmune mechanisms

Question 312

Which of the following glycolytic enzymes catabolize the metabolic steps leading to the formation phosphoenolpyruvate:
enolase
glycerate kinase
aldolase
pyruvate kinase

Answer 312

pyruvate kinase

Question 313

The blood level of which of the mentioned metabolites is significantly increased during active muscle contraction:
amino acids
none of them
glucose
lactate

Answer 313

lactate

Question 314

Which of the following statements about the malate-aspartate shuttle is not true:
1.the pair of substrates involved in the shuttle are oxaloacetate and malate
2.the shuttle is bidirectional
3.transferred by the shuttle mechanism, two pairs of reducing equivalents after their submission to the respiratory chain, lead to the synthesis of 4 ATP molecules
4.cytoplasmic and mitochondrial malate dehydrogenase participate in shuttle

Answer 314

3.transferred by the shuttle mechanism, two pairs of reducing equivalents after their submission to the respiratory chain, lead to the synthesis of 4 ATP molecules

Question 315

Which of mentioned metabolic pathways in the liver for conversion of glucose do not occur during fasting (between meals):
1.gluconeogenesis
2.degradation of glycogen
3.degradation of glucose, in order to provide substrate for fatty acids synthesis
4.degradation of glucose-6-phosphste to glucose

Answer 315

4.degradation of glucose-6-phosphste to glucose

Question 316

Which of the following enzymes involved in gluconeogenesis, it is the most important regulatory enzyme in the process, subjected to allosteric regulation of variety of modulators:
pyruvate carboxylase
fructose-1,6-bisphosphatase
glucose-6-phosphatase
phosphoenolpyruvate-carboxykinase (PEPCK)

Answer 316

fructose-1,6-bisphosphatase

Question 317

Which of the following metabolites of glycolysis is obtained in an oxidation step and is a macroergic phosphate compound:
glyceraldehyde 3-phosphate
1,3-bisphosphoglycerate
phosphoenol pyruvate
pyruvate

Answer 317

1,3-bisphosphoglycerate

Question 318

Which of the mentioned mtabolites (substances) serves as an energetic source (alternative to glucose) during prolonged fasting:
fructose
glycerol
ketone bodies

Answer 318

ketone bodies

Question 319

Which of the following statements about the oxidative decarboxylation of pyruvate is wrong:
the product of oxidative decarboxylation of pyruvate is Acetyl CoA
oxidative decarboxylation of pyruvate is carried in multienzyme complex called pyruvate dehydrogenase complex
oxidative decarboxylation of pyruvate takes place in the mitochondria
NADP+ serves as a coenzyme in the pyruvate dehydrogenase complex and NADPH is obtained

Answer 319

NADP+ serves as a coenzyme in the pyruvate dehydrogenase complex and NADPH is obtained

Question 320

In which of the following cells an anaerobic glycolysis is performed:
white muscle fibers (during active contraction)
cells of the renal medulla
erythrocytes
cells of the crystalline lens

Answer 320

erythrocytes

Question 321

Which of the following glycolytic enzymes catalyzes an irreversible metabolic step:
glycerate kinase
aldolase
glyceraldehyde 3-phosphate dehydrogenase
pyruvate kinase

Answer 321

pyruvate kinase

Question 322

Which of the following hormones by its effect on the liver cells, results in the formation of active kinase dephosphorylated form of the enzyme phosphofructokinase 2:
Glucagon
Adrenaline
None of the mentioned above
Insulin

Answer 322

Insulin

Question 323

Which of the following pairs of hormones appears to be, depending on the quantitative ratio of their blood levels, the main regulator of the metabolism of energetic biomolecules (glucose, fatty acids):
insulin / glucagon
glucagon / cortisol
insulin / cortisol
glucagon / adrenaline

Answer 323

insulin / glucagon

Question 324

Which of the following enzymes involved in the breakdown of carbohydrates in the digestive tract of humans, have small intestine origin?
sucrose
glucoamylase
lactase
α- amylase

Answer 324

lactase

Question 325

Which of the following enzymes involved in glycogen metabolism, catalyzes the degradation of α-1,4-glycosidic bond:
phosphoglucomutase
amylo-1,4 → 1,6-transglucosidase
glycogen phosphorylase
glycogen synthase

Answer 325

glycogen phosphorylase

Question 326

In insufficiency of which of the following enzymes involved in the degradation of galactose, pathological condition known as galactose intolerance or galactosemia develops:
С4- epimerase
galactose-1-phosphate-uridil transferase
none of the mentioned above
Galactokinase

Answer 326

galactose-1-phosphate-uridil transferase

Question 327

To which of the following enzymes functioning in gluconeogenesis, acetyl-CoA is an allosteric activator:
glucose-6-phosphatase
PEPC
pyruvate carboxylase
fructose-1,6-bisphosphatase

Answer 327

pyruvate carboxylase

Question 328

Which of the following statements about the structure of glycogen is wrong:
glycogen molecule has a branched structure
in the straight sections of the polysaccharide chains glucose residues are joined by α-1,4-glycosidic bond
glycogen is heteropolysaccharide
in the branches sections in the polysaccharide chain the bond is α-1,6-glycosidic

Answer 328

glycogen is heteropolysaccharide

Question 329

Which of the following coenzymes is a cofactor of glyceraldehyde 3-phosphate dehydrogenase, which catalyses an oxidative step in glycolysis:
FMN
FAD
NAD+
NАDP+

Answer 329

NAD+

Question 330

Which of these metabolites is the allosteric activator of phosphorylated glycogen synthase b:
АTP
АМP
glucose-6-phosphate
fructose-2,6-bisphosphate

Answer 330

АМP

Question 331

Which of the following metabolites of glucose is a a key metabolite of glucose metabolism:
lactate
glucose 6-phosphate
fructose-1,6-biphosphate
pentose-5-phosphate

Answer 331

glucose 6-phosphate

Question 332

When you consider that for the synthesis of one molecule glucose in gluconeogenesis two molecules pyruvate are used, choose the correct answer of the question – how many molecules ATP are spent in the process of gluconeogenesis
3 molecules ATP
2 molecules ATP
6 molecules ATP
neither one single molecule ATP

Answer 332

6 molecules ATP

Question 333

In which of the following cell types malate-aspartate shuttle mechanism does not function:
hepatocytes
brain cells
kidney cells
heart muscle

Answer 333

brain cells

Question 334

Which of the following enzymes of the glycolytic metabolic chain catalyzes the step, occurring phosphorylation in the substrate chain, ie carries out the synthesis of ATP:
Phosphofructokinase 1
Phosphoglucomutase
Hexokinase
Pyruvatekinase

Answer 334

Phosphofructokinase 1

Question 335

In the failure of which of these enzymes involved in the catabolism of fructose the hereditary disease “congenital fructose intolerance” is developed:
triosokinase
none of the above mentioned
Fructokinase
Aldolase B

Answer 335

Aldolase B

Question 336

With the deficiency of which of the following enzymes of the pentose-phosphate pathway is associated the risk of hemolytic anemia:
Phosphogluconolaktonase
Transaldolase
Transketolase
Glucose-6-phosphate dehydrogenase

Answer 336

Glucose-6-phosphate dehydrogenase

Question 337

Which of the following metabolites pairs performes the transfer of reducing equivalents of NAD.H from the cytosol to the respiratory chain in malate-aspartate shuttle mechanism:
malate- aspartate
malate/oxaloacetate
none of the mentioned above
DHAP / glycerol-3-phosphate

Answer 337

malate- aspartate

Question 338

Which of the following statements about the metabolism of liver glycogen is true:
a.its digested in periods of fasting
b.glucagon stimulates its synthesis
c.adrenaline stimulates its synthesis
d.In its degradation lactate is released in the blood

Answer 338

In its degradation lactate is released in the blood

Question 339

Which of mentioned biomolecules is the major energetic source for skeletal muscles during their intensive and non-continuous contractions:
glucose
none of them
fatty acids
ketone bodies

Answer 339

fatty acids

Question 340

How many of the metabolic steps in glycolysis are irreversible
2
5
none
3

Answer 340

3

Question 341

Which of the following symptoms are typical for mono- and disaccharidases malabsorption (intolerance) and lactose intolerance?
1) diarrhea
2) intestinal distension
3) painful colics
4) meteorism
1+3
2+4
1+2+3
1+2+3+4

Answer 341

1+3

Question 342

Which of the following enzymes involved in the glycolysis is the major regulatory enzyme of glycolysis:
Phosphofructokinase-2 (PFK-2)
Phosphofructokinase-1 (PFK-1)
Phosphoglycerate kinase
Aldolase

Answer 342

Phosphofructokinase-1 (PFK-1)

Question 343

Which of the following metabolic steps of gluconeogenesis is common for glycolysis and gluconeogenesis:
fructose-1,6-bisphosphate → fructose-6-phosphate
oxaloacetate → phosphonenolpyruvate
pyruvate →oxaloacetate
fructose-6-phosphate → Glucose-6-phosphate

Answer 343

fructose-1,6-bisphosphate → fructose-6-phosphate

Question 344

By which of the following transports the transition of glucose through the luminal membrane of intestinal epithelial cells is performed:
active transport
enhanced diffusion and secondary active transport
passive diffusion
secondary active transport

Answer 344

secondary active transport

Question 345

Glycerol is a non-carbohydrate precursor for the synthesis of glucose in gluconeogenesis.To which of the following metabolites of gluconeogenesis turns the glycerol to:
phosphonenolpyruvate
pyruvate
dihydroxyacetone phosphate
fructose-6-phosphate

Answer 345

dihydroxyacetone phosphate

Question 346

Which of the listed deficiencies (of enzymes and / or vitamins) lead to lactic acidosis?
1)thiamine
2) erythrocyte enzymes of glycolysis
3) enzymes of pyruvate dehydrogenase complex
4) muscle enzymes of glycolysis

Answer 346

1)thiamine

Question 347

Glycosylated hemoglobin is an indicator of:
prolonged hyperglycaemia
prolonged hypoglycaemia
impaired pentose phosphate function
reduced glucose uptake into erythrocytes

Answer 347

prolonged hyperglycaemia

Question 348

Which of the following enzymes catalyzes the synthesis of fructose-2,6-bisphosphate, appearing as the strongest activator of the regulatory enzyme of glycolysis:
hexokinase
phosphofructokinase 2
phosphofructokinase 1
phosphoglycerate kinase

Answer 348

phosphofructokinase 2

Question 349

Which of the following statements about the enzyme glucose-6-phosphatase is wrong:
a.the highest concentration of enzyme is found in skeletal muscle cells
b.the synthesis of the enzyme is induced by the hormone cortisol
c.the enzyme is localized in the endoplasmic reticulum
d.the enzyme catalyzes the hydrolysis of glucose-6-phosphate to glucose-free, as it passes from the liver into the blood to maintain normal blood glucose level

Answer 349

a.the highest concentration of enzyme is found in skeletal muscle cells

Question 350

Which of the following statements about the transport of glucose from the blood into the cells of skeletal muscle is wrong:
a.the insulin induces the biosynthesis of an enzyme which catalyzes phosphorylation of b.the free glucose to glucose-6-phosphate
c.the transport is carried out by a glucose transporter (facilitated diffusion)
d.the glucose enters the cells of the skeletal muscle by the concentration gradient
e.insulin stimulates glucose transport through the export of glucose carriers from the cell on the cell membrane, i.e. - By increasing the number of transporters on the cell membrane

Answer 350

d.the glucose enters the cells of the skeletal muscle by the concentration gradient

Question 351

Which of the following statements about the influence of insulin on blood glucose level is wrong:
a.stimulates glycolysis in the liver
b.does not stimulate glucose transport in adipose tissue
c.reduces the level of blood glucose by accelerating its transport from the blood into d.insulin-dependent tissues
e.stimulates the synthesis of liver and muscle glycogen

Answer 351

b.does not stimulate glucose transport in adipose tissue

Question 352

In which of the following types of cells the transport of glucose is insulin-independent:
1) adipocytes
2) brain
3) skeletal muscle cells
4) erythrocytes

Answer 352

2) brain
4) erythrocytes

Question 353

Which amino acids are required for the synthesis of creatine phosphate?
1) tyrosine;
2) glycine;
3) arginine;
4) lysine;
5) methionine
1+2+5
2+3+5
1+2+3
1+3+4
2+4+5

Answer 353

2+3+5

Question 354

The simultaneous increase of the AST and ALT serum levels is used to diagnose a disease of the:
brain
muscules
stomach
prostate
liver

Answer 354

liver

Question 355

Which of the following chemical bonds/interactions are involved in stabilizing the tertiary structure of proteins?
1) ion, dipole and ion-dipole interactions;
2) hydrophobic interactions;
3) peptide bonds;
4) hydrogen bonds between radicals;
5) hydrogen bonds between closely spaced peptide groups
1+3+5
1+2+4
2+3+4
1+4+5
1+2+3

Answer 355

2+3+4

Question 356

Identify the true statements about glutamate dehydrogenase.
1) oxidatively deaminates glutamate together with NAD;
2) reductively aminates α-ketoglutarate together with NADPH;
3) oxidatively deaminates glutamate together with FAD;
4) it is activated allosterically by ATP and GTP
5) it is localized in the mitochondria.
1+2+4
1+2+5
2+3+4
1+4+5
2+3+5

Answer 356

2+3+5

Question 357

User
Which of the following changes are observed in hemolytic jaundice?
1) increased urobilinogen in urine;
2) increased bilirubin in urine;
3) very dark stools;
4) increased indirect bilirubin in serum; 5) increased direct bilirubin in serum.
1+2+3
1+3+4
1+4+5
2+3+4
2+4+5

Answer 357

1+3+4

Question 358

Heme biosynthesis is a process:
1) that is highly prevalent in the liver and bone marrow;
2) localized in mitochondria and cytosol of cells;
3) which is highly prevalent in mature erythrocytes;
4) which requires succinyl-CoA and glycine;
5) which requires carbamoyl phosphate and aspartate.
1+3+4
1+3+5
1+2+4
2+3+4
2+3+5

Answer 358

2+3+4

Question 359

Heme biosynthesis is a process:
1) that is highly prevalent in the liver and bone marrow;
2) localized in mitochondria and cytosol of cells;
3) which is highly prevalent in mature erythrocytes;
4) which requires succinyl-CoA and glycine;
5) which requires carbamoyl phosphate and aspartate.
1+3+4
1+3+5
1+2+4
2+3+4

Answer 359

1+2+4

Question 360

Indicate the correct answers describing the features of the protein ubiquitin.
1) it is a protein fragment obtained as a result of the proteolytic maturation of the insulin molecule;
2) it is a protein fragment obtained as a result of the proteolytic maturation of pituitary hormones;
3) it is a small protein that binds covalently to other proteins through its glycine terminal carboxyl group and marks them for subsequent degradation;
4) it is an enzyme that is found in all cells and participates in processes of proteolytic maturation of hormones;
5) it is a protein through which the cell directs “aged” proteins to the proteasome, where they are degraded.
1 + 3
2 + 3
3 + 4
3 + 5
4 + 5

Answer 360

3 + 5

Question 361

The chemical bond between the pentose and the phosphoric acid in nucleotides is:
О-glycosidic
N-glycosidic
phosphodiester bond
ester bond
peptide bond

Answer 361

phosphodiester bond

Question 362

Which of the end products of heme degradation are increased in parenchymal jaundice?
1) urobilinogen in urine;
2) bilirubin in urine;
3) indirect bilirubin in serum;
4) direct bilirubin in serum;
5) stercobilin in feces.
2+4
1+3
1+2
3+4
4+5

Answer 362

4+5

Question 363

Carbamoylphosphate synthetase I, supplying carbamoylphosphate for the urea cycle:
1) is located in the mitochondria of hepatocytes;
2) is located in the cytosol of hepatocytes;
3) is a regulatory enzyme;
4) is activated allosterically by N-acetylglutamate;
5) is activated allosterically by N-acetylglutamine.
1+2+4
1+4+5
3+4+5
1+3+4
2+3+5

Answer 363

1+2+4

Question 364

Which of the following enzymes in the synthesis of purine nucleotides are under allosteric control?
1) phosphoribosylpyrophosphate synthetase;
2) formyl transferase;
3) glutamine-phosphoribosylpyrophosphate amidotransferase;
4) adenylosuccinate lyase;
5) xanthine oxidase.
2+5
1+3
1+4
2+3
4+5

Answer 364

1+3

Question 365

Which of the following molecules are produced when heme is broken down?
1) uric acid;
2) bilirubin;
3) biliverdin;
4) urea;
5) creatinine.
1+2
1+3
2+3
3+4
2+5

Answer 365

2+3

Question 366

Heme is a cofactor of:
1) phosphofructokinase-1;
2) citrate synthase;
3) cytochromes;
4) ATP synthase;
5) catalase.
1+2
2+3
3+4
4+5
3+5

Answer 366

3+5

Question 367

Tyrosine is the precursor for the synthesis of:
1) NAD;
2) melanine;
3) melatonin;
4) thyroid hormones;
5) corticosteroids.
1+2
2+4
2+3
2+5
4+5

Answer 367

2+3

Question 368

Which disease occurs with a genetic defect in an enzyme that breaks down valine, isoleucine, and methionine?
pellagra
alkaptonuria
merhylmalonylemina
albinism
Lesch-Nyhan syndrome

Answer 368

merhylmalonylemina

Question 369

What features are characteristic of hemoglobin?
1) consists of 4 different polypeptide chains;
2) consists of 4 polypeptide chains, two by two identical;
3) each polypeptide chain contains heme;
4) heme iron is divalent;
5) heme iron is trivalent.
1+3+5
2+3+5
1+3+4
2+3+4
1+2+3

Answer 369

2+3+4

Question 370

The breakdown of heme produces:
1) carbon monoxide;
2) carbon dioxide;
3) bile acids;
4) bile pigments;
5) uric acid.
4+5
1+4
1+2
2+3
1+5

Answer 370

4+5

Question 371

Indicate the true statements about folic acid.
1) its active form is tetrahydrofolate;
2) its active form is dihydrofolate;
3) supplies one-carbon groups for the synthesis of the purine ring;
4) supplies one-carbon groups for the synthesis of the pyrimidine ring;
5) supplies one-carbon groups for creatine synthesis.
2+4
4+5
1+3
1+2
3+5

Answer 371

1+3

Question 372

Identify the true statements about the synthesis of pyrimidine nucleotides.
1) the pyrimidine ring is built on a ribose phosphate residue;
2) the pyrimidine ring is formed first and then a ribose phosphate residue is added to it;
3) tetrahydrofolate derivatives are needed to obtain dTMP;
4) S-adenosylmethionine is required to produce dTMP;
5) all enzymes have a cytosolic localization.
2+5
1+3
1+2
2+3
4+5

Answer 372

2+3

Question 373

Identify the true statements about phenylketonuria.
a. It is caused by deficiency of phenylalanine hydroxylase.
b. It is caused by hyperactive phenylalanine hydroxylase.
c. It is characterized by an accumulation of homogentisinate
d. It is characterized by an accumulation of tryptophan.
e. It is caused by reduced activity of dihydrofolate reductase.

Answer 373

a. It is caused by deficiency of phenylalanine hydroxylase.
c. It is characterized by an accumulation of homogentisinate

Question 374

The nitrogen atom in carbamoyl phosphate required for the synthesis of pyrimidines originates from:
glutamate
ammonia
aspartate
glutamine
glycine

Answer 374

ammonia

Question 375

Which vitamin is present in the structure of FAD and FMN?
Vit B1 (thiamin)
Vit B2 (riboflavin)
Vit B3 (niacin)
Vit B9 (folic acid)
Vit B12 (cobalamin)

Answer 375

Vit B2 (riboflavin)

Question 376

Which of the following compounds is NOT a metabolite involved in porphyrin biosynthesis?
porphobilinogen
glycine
succinyl-CoA
uroporphyrinogen
UDP-glucuronate

Answer 376

UDP-glucuronate

Question 377

Which of the following reactions requires S-adenosylmethionine as a methyl group donor?
The conversion of norepinephrine to epinephrine
The conversion of phenylalanine to tyrosine.
The synthesis of purines.
The conversion of dUMP to dTMP.
The conversion of glutamate to glutamine.

Answer 377

The conversion of norepinephrine to epinephrine

Question 378

Which of the following compounds is a cofactor of the enzymes heme oxygenase and biliverdin reductase?
UDP-glucoronate
NADH
pyridoxal phosphate
NADPH
ascorbic acid

Answer 378

NADPH

Question 379

Which are the regulatory enzymes in the synthesis of pyrimidine nucleotides?
1) carbamoyl phosphate synthetase II;
2) dihydroorotase;
3) dihydroorotate dehydrogenase;
4) aspartate transcarbamoylase;
5) carbamoyl phosphate synthetase I.
1+3
1+4
2+5
3+5
4+5

Answer 379

1+4

Question 380

Cytotoxic ammonia is neutralized by:
1) the synthesis of glutamine in the brain;
2) the synthesis of alanine in muscles; 3) transdeamination reactions;
4) formation of ammonium ions in the brain;
5) reductive amination of alpha-ketoglutarate.
1+2+4
1+2+5
2+3+4
1+4+5
2+3+5

Answer 380

1+2+5

Question 381

Which biosynthetic processes take place with the participation of tetrahydrofolic acid derivatives as cofactors?
1) the synthesis of purines (C2 and C8 atoms);
2) the synthesis of choline from ethanolamine;
3) the synthesis of methionine from homocysteine;
4) creatine synthesis;
5) the synthesis of TMF.

Answer 381

1) the synthesis of purines (C2 and C8 atoms);
3) the synthesis of methionine from homocysteine;
5) the synthesis of TMF.

Question 382

Which of the following enzymes in the synthesis of pyrimidine nucleotides are under allosteric control?
1) carbamoyl phosphate synthetase II; 2) dihydroorotase;
3) dihydroorotate dehydrogenase;
4) aspartate transcarbamoylase;
5) orotate phosphoribosyltransferase.
2+5
1+4
1+3
3+4
1+5

Answer 382

1+4

Question 383

Tyrosinemias are observed in genetically determined insufficiency of enzymes from the catabolite chain of:
histidine
tryptophan
valine
leucine
phenylalanine

Answer 383

phenylalanine

Question 384

Which amino acids are sources of one-carbon residues for tetrahydrofolic acid?
serine, histidine, arginine
serine, tyrosine, tryptophan
histidine, glycine, valine
tryptophan, histidine, glutamate
serine, histidine, tryptophan

Answer 384

serine, histidine, arginine

Question 385

The function of haptoglobin is:
1) to bind free heme;
2) to participate in the synthesis of hemoglobin for erythrocytes;
3) to transport the hemoglobin/haptoglobin complex through the kidneys;
4) to prevent loss of hemoglobin from the kidneys;
5) to preserve iron in the body.
3+5
1+3
2+4
4+5
1+2

Answer 385

3+5

Question 386

Which statements are true about the hormone hepcidin?
1) increases serum iron content;
2) lowers serum iron content;
3) binds to the iron exporter ferroportin; 4) binds to the iron transport protein transferrin;
5) binds to the iron-depositing protein ferritin.
2+5
1+3
1+4
2+3
4+5

Answer 386

2+3

Question 387

Protein denaturation is a process that: 1) changes the amino acid composition of the protein molecule;
2) destroys the primary structure of the protein molecule;
3) leads to loss of biological activity of the protein;
4) increases the chemical reactivity of the polypeptide chain of the protein;
5) destroys the secondary, tertiary and quaternary level of organization of the protein
1+2+5
3+4+5
1+2+3
2+3+5
1+3+4

Answer 387

2+3+5

Question 388

Which cofactors are involved in the oxidative decarboxylation of α-keto acids?
1) NAD+;
2) NADP+;
3) lipoic acid;
4) ascorbic acid;
5) coenzyme A (CoA-SH).
1+3+4
1+3+5
2+3+4
2+3+5
3+4+5

Answer 388

1+3+5

Question 389

The amino acid arginine is NOT a precursor for the synthesis of:
creatine phosphate
ethanolamine
nitric oxide
ornithine
polyamines

Answer 389

ethanolamine

Question 390

Which nucleotide is a secondary mediator of the action of adrenaline in muscles and glucagon in liver?
ATP
ADP
AMP
cyclic 3’,5’-АMP
cyclic 3’,5’-GMP

Answer 390

AMP

Question 391

Which of the following statements about the quaternary structure of proteins are true?
1) the achievement of such a structure is due to non-covalent (weak) interactions between two or more polypeptide chains;
2) proteins with a quaternary structure represent supramolecular complexes made up of two or more polypeptide chains (subunits) connected by covalent bonds;
3) the quaternary structure is mandatory for the manifestation of the biological activity of proteins;
4) the quaternary structure is necessary for those proteins that will be targeted for degradation;
5) the acquisition of a quaternary structure is one of the reasons for the existence of different isoforms and regulation in some proteins.
1+5
1+3
2+4
3+5
1+4

Answer 391

1+5

Question 392

Which of the following statements about the urea cycle are true?
1) occurs in the mitochondria and the cytosol;
2) occurs in endoplasmic reticulum and cytosol;
3) proceeds in the liver;
4) occurs intensively after taking a balanced meal;
5) does not require energy.
3+5
1+2
4+5
1+3
2+4

Answer 392

1+3

Question 393

Name the enzymes involved in the folding of polypeptide chains.
1) prolyl cis-trans isomerase;
2) protein disulfide isomerase;
3) prolyl hydroxylase;
4) lysyl hydroxylase;
5) chaperones.
1+2+5
2+3+4
1+2+3
1+4+5
1+3+4

Answer 393

1+2+5

Question 394

Which of the following statements about nucleosides are true?
1) they consist of nitrogen base and pentose;
2) in the structure of nucleic acids they are connected by 3’-5’-phosphodiester bonds;
3) The N-glycosidic bond between the base and the pentose in purine nucleosides is at N1;
4) The N-glycosidic bond between the base and the pentose in pyrimidine nucleosides is at N1;
5) syn-conformers of nucleosides predominate.
3+5
3+4
1+2
1+4
2+5

Answer 394

1+4

Question 395

Which of the following chemical bonds/interactions are involved in stabilizing the secondary structure of proteins?
ion, ion-dipole, dipole interactions
hydrogen bonds between side radicals of closely positioned amino acids
peptide bonds
disulfide bonds
hydrogen bonds between closely positioned peptide groups

Answer 395

hydrogen bonds between side radicals of closely positioned amino acids

Question 396

Identify the correct neurotransmitter/amino acid combination from which the corresponding neurotransmitter is synthesized.
gamma-aminobutirate from glutamate
gamma-aminobutirate from aspartate
serotonin from tyrosine
serotonin from sulfur-containing amino acids
norepinephrine and epinephrine from tryptophan

Answer 396

gamma-aminobutirate from glutamate

Question 397

Which of the following statements about heme synthesis are true?
1) the main regulatory enzyme is δ-aminolevulinate (ALA) dehydratase;
2) the main regulatory enzyme is δ-aminolevulinate (ALA) synthase;
3) heme is a major allosteric inhibitor of the regulatory enzyme;
4) porphyria can develop with ALA-synthase deficiency;
5) heme is synthesized in the bone marrow and liver.
2+4+5
1+3+4
2+3+5
1+4+5
1+2+3

Answer 397

2+4+5

Question 398

Which of the following proteins are involved in iron transport?
1) transferrin;
2) ceruloplasmin;
3) lactoferrin;
4) ferritin;
5) hemosiderin.
2+5
1+3
1+2
2+4
4+5

Answer 398

1+3

Question 399

How are purine nucleotides synthesized in the “de novo” pathway?
1) the synthesis starts from carbamoyl phosphate and aspartate;
2) synthesis starts from glycine and aspartate;
3) the purine ring is built by attaching atoms to phosphoribosylpyrophosphate;
4) the phosphoribosyl residue joins an already formed purine ring;
5) glycine and glutamine are involved in the synthesis.
1+2
2+4
2+5
3+5
4+5

Answer 399

1+2

Question 400

Which of the following statements about the iron metabolism is true?
physiologically, iron is deposited in the form of hemosiderin
transferrin can only bind heme iron
transferrin can only bind the ferrous (Fe2+) form of iron
hepcidin lowers serum iron by blocking ferroportin
hepcidin lowers serum iron by activating ferroportin

Answer 400

hepcidin lowers serum iron by blocking ferroportin

Question 401

In transamination:
1) amino acids are converted into biogenic amines;
2) one amino acid is converted to a keto acid and another keto acid is converted to an amino acid;
3) pyridoxal phosphate is involved as a cofactor;
4) amino groups of amino acids are released as free ammonia;
5) NADPH is involved as a cofactor
1+2
2+4
2+3
2+5
4+5

Answer 401

2+3

Question 402

Heme biosynthesis is a process:
1) that is highly prevalent in the liver and bone marrow;
2) localized in mitochondria and cytosol of cells;
3) which is highly prevalent in mature erythrocytes;
4) which requires succinyl-CoA and glycine;
5) which requires carbamoyl phosphate and aspartate.
1+3+4
1+3+5
1+2+4
2+3+4

Answer 402

1+2+4

Question 403

Which of the following substances are ketone bodies with metabolic importance for tissues:
1)acetoacetate
2) oxaloacetate
3) β- hydroxybutyrate
4) acetone
1+2+3
2+3+4
2+3
1+3

Answer 403

1+3

Question 403

Which of the following cofactors supplies reducing equivalents for the action of the enzyme HMG-CoA reductase?
NADP.Н
none of the above mentioned
FAD.Н2
NAD.H

Answer 403

NAD.H

Question 404

Which of the enzymes who catalyze reactions in the synthesis of glycerolipids is regulatory?
glycerol-3P-acyltransferase
phosphatide phosphatase
phosphatidylinositol synthase
diacylglycerol acyltransferase

Answer 404

diacylglycerol acyltransferase

Question 405

Which of the following statements for the synthesis of saturated fatty acids with an even number of carbon atoms (palmitic acid) is false?
synthesis takes place in the cytosol
NAD.H serves as a donor of reducing equivalents
NADP.H serves as a donor of reducing equivalents
direct substrate for the synthesis is malonyl-CoA

Answer 405

NAD.H serves as a donor of reducing equivalents

Question 406

Which of the following statements about the regulation of enzyme activity of 7α-hydroxylase which regulates the conversion of cholesterol to bile acids in the liver is false?
a. the catalytic activity of 7α-hydroxylase is regulated by phosphorylation / dephosphorylation, and the active form of b. the enzyme is dephosphorylated
c. bile acids inhibit the enzyme
d. cholesterol activates 7α-hydroxylase
e. in vit. C deficiency catalyzed by 7α-hydroxylase metabolic step slows down

Answer 406

d. cholesterol activates 7α-hydroxylase

Question 407

Which of the following coenzymes serves as a donor of reducing equivalents in the synthesis of fatty acids in acyl synthetase complex?
FMN.Н2
FAD.Н2
NADP.Н
NAD.Н

Answer 407

NADP.Н

Question 408

A key metabolite in the synthesis of cholesterol and ketone bodies is a one of the following compounds:
a. mevalonic acid
b. NADPН+Н+
c. 3-hydroxy-3-methylglutaryl-CоА
d. squalene

Answer 408

c. 3-hydroxy-3-methylglutaryl-CоА

Question 409

Which of the following statements about the physiological functions of eicosanoids is false?
a. participate in inflammatory processes in injuries and infections
b. all eicosanoids act as vasoconstrictors
c. some of them regulate smooth muscle contractions (intestine, uterus)
d. some of the eicosanoids are involved in platelet aggregation

Answer 409

b. all eicosanoids act as vasoconstrictors

Question 410

Increased concentrations of which of these transport forms of lipids decreases the risk of developing atherosclerosis and coronary heart disease?
LDL
IDL
VLDL
HDL

Answer 410

HDL

Question 411

Which of the following biological functions of cholesterol is not true?
a. cholesterol serves as a precursor for bile acids synthesis
b. cholesterol serves as a precursor for steroid hormone synthesis
c. cholesterol serves as a precursor for vitamin E synthesis
d. cholesterol participates in the construction of the cell e. membranes as a stabilizing component

Answer 411

c. cholesterol serves as a precursor for vitamin E synthesis

Question 412

Oxidation of unsaturated fatty acids occurs in:
mitochondria
cytoplasm
lysosomes
endoplasmic reticulum

Answer 412

endoplasmic reticulum

Question 413

Which of the following mechanisms activating the biosynthesis of fatty acids from insulin is incorrect?
a. insulin with its action gives the active nonphosphorylated form of the regulatory enzyme acetyl-CoA carboxylase
b. insulin with its action activates the enzyme glycerol-3-phosphate acyl transferase, forming its nonphosphorilated
c. insulin with its action induces the biosynthesis of the regulatory enzyme of fatty acid synthesis - acetyl-CoA carboxylase
d. insulin with its action induces the biosynthesis the multifunction enzyme of acyl synthetase complex (АSC)

Answer 413

b. insulin with its action activates the enzyme glycerol-3-phosphate acyl transferase, forming its nonphosphorilated

Question 414

Which of the following types of lipids is not a component of the membrane structures?
cholesterol
triacylglycerols
cardiolipins
phosphatidylethanolamine

Answer 414

triacylglycerols

Question 415

Which of the following reactions and processes provide reducing equivalents (NADPH) used in the synthesis of FA?
1) anaerobic glycolysis
2) pentose phosphate pathway
3) reaction catalyzed by malate dehydrogenase
4) reaction catalyzed by malate enzyme
2+3
2+4
2+3+4
1+2+3

Answer 415

2+3

Question 416

Which of the following statements about the metabolism of energetic biomolecules in a patient suffering from a carnitine deficiency is wrong?
there will be deficiency of ATP for gluconeogenesis leading to lowering glucose level in the blood (hypoglycaemia) in fasting state.

the levels of fatty acids in the blood will be low

the transport of long-chain fatty acids into the mitochondria of hepatocytes will be reduced and β-oxidation of fatty acids will be slower

ketone bodies synthesis will be reduced and their level in the blood will be low

Answer 416

the levels of fatty acids in the blood will be low

Question 417

Which of the following compounds are cholesterol derivatives?
1)aldosterone
2) adrenaline
3)cortisol
4)cholic acid
3+4
1+2+3
1+3
1+3+4

Answer 417

1+3

Question 418

Which enzyme is involved in the synthesis of cholesterol esters in HDL?
lecithin - cholesterol acyltransferase (LCAT)
Acetyl-CoA-cholesterol acyltransferase-(ACAT)
Pancreatic lipase
hormone-dependent lipase

Answer 418

lecithin - cholesterol acyltransferase (LCAT)

Question 419

Eicosatetraenoic acid (C20, 4:5,8,11,14) is a precursor for the synthesis of:
1) prostanoids with 2 double bonds
2) leukotrienes with 3 double bonds
3) lipoxins with 4 double bonds
4) none of the above mentioned
1+3
2+4
1+2+3
none

Answer 419

2+4

Question 420

Which of the following hormones stimulates ketogenesis in periods of fasting?
cortisol
glucagon
none of the above mentioned
insulin

Answer 420

glucagon

Question 421

How many metabolic steps are required for the decoupling (oxidation) of each two-carbon fragment of the long fatty acid chain in β-oxidation?
8
4
6
2

Answer 421

4

Question 422

Which of the following types of genetic defects, leading to development of inherited hyperlipoproteinemias, is the cause of familial hypercholesterolemia, characterized by elevated blood levels of LDL and considered as a risk factor for atherosclerosis?

genetic defects affecting enzymes (for example, lipoprotein lipase or lecithin-cholesterol acyltransferase-) involved in the metabolism of lipoproteins

genetic defects resulting in decreased synthesis of receptor LDL

none of them

genetic defects affecting the synthesis, structure, or secretion of apoproteins

Answer 422

genetic defects resulting in decreased synthesis of receptor LDL

Question 423

Which of the following compounds is a key (a key metabolite) in the synthesis of most glycerolipids?
phosphatidic acid
choline
CDP-choline
CDP- diacylglycerol

Answer 423

CDP- diacylglycerol

Question 424

Which of the following metabolites is a product of the degradation of ketone bodies (ketolysis)?
acetyl-CоА
malonyl -CоА
none of the above mentioned
succinyl -CоА

Answer 424

acetyl-CоА

Question 425

The oxidative phase of the PPP (pentose phosphate pathway) is important for:
1) cholesterol synthesis
2) synthesis of ATP
3) FA synthesis
4) gluconeogenesis
none
2+4
1+3
1+2+3

Answer 425

1+3

Question 426

Which of the following pathways of lipid metabolism occurring in adipose tissue is stimulated by insulin?
fatty acids synthesis (lipogenesis)
none of them
triacylglycerols degradation (lipolysis)
fatty acids degradation (β-oxidation)

Answer 426

fatty acids synthesis (lipogenesis)

Question 427

Which of the following essential polyunsaturated FA (PUFA) are supplied only from foods of animal origin.
1)linoleic acid
2)arachidonic acid
3)eicosapentaenoic acid
4)linolenic acid
2+3+4
2+3
1+4
1+2+3

Answer 427

2+3

Question 428

Which of the following compounds is the direct donor of 14 of the 16 carbon atoms in the synthesis of palmitic acid?
malonyl-CоА
acyl-CоА
acetyl-CоА
methilmalonyl-CоА

Answer 428

acetyl-CоА

Question 429

Which of the following lipoprotein complexes transport the “Bad” cholesterol and raising of their levels is a risk factor for atherosclerosis?
LDL
VLDL
HDL
chylomicrons

Answer 429

VLDL

Question 430

Which of the following biological effects are typical for PGE2?

1)bronchoconstrictor
2)vasodilator
3)inhibits the secretion of gastric juice
4) inhibits the uterine contractions
2+4
2+3+4
1+2+3
2+3

Answer 430

2+3+4

Question 431

Which of the following enzymes is regulatory in degradation of triacylglycerols in adipose tissue?
lipoprotein lipase
adipolitic lipase
phospholipase
glycerol kinase

Answer 431

adipolitic lipase

Question 432

Which of the following statements about the activity of the regulatory enzyme of fatty acid biosynthesis, acetyl-CoA carboxylase is false?
the activity is influenced by the action of hormones,as insulin stimulates the enzymatic activity

the activity is regulated by the mechanism of covalent modification (phosphorylation / dephosphorylation), аs the active form is phosphorylated.

the activity is regulated by the mechanism of covalent modification (phosphorylation / dephosphorylation), the active form is dephosphorylated.

the activity of the enzyme is regulated allosterically as citrate is allosteric activator

Answer 432

the activity is regulated by the mechanism of covalent modification (phosphorylation / dephosphorylation), аs the active form is phosphorylated.

Question 433

Which of the following statements about ketone bodies is wrong?
substrate for the synthesis of ketone bodies is acetyl CoA,
obtained from the oxidative decarboxylation of pyruvate

ketone bodies are acetoacetate, β-hydroxybutyrate and acetone, as acetone is product of acetoacetate degradation.

ketone bodies are an energy source alternative of glucose
the concentration of the β-hydroxybutyrate in the blood is usually higher than that of the acetoacetate

Answer 433

ketone bodies are acetoacetate, β-hydroxybutyrate and acetone, as acetone is product of acetoacetate degradation.

Question 434

Which of the following nucleoside-triphosphate is used to activate the so-called “polar head” in the synthesis of phosphoglycerides?
GTP
CTP
none of them
UTP

Answer 434

CTP

Question 435

Arachidonic acid is converted to biologically active eicosanoids in two metabolic pathways: cyclooxygenase and lipoxygenase. Which of the following statements about obtaining the eicosanoids is wrong?

aspirin is an irreversible inhibitor of the enzyme lipoxygenase

lipoxins are obtained by successively co action of 2 lipoxygenases

in the lipoxygenase pathway occurs the synthesis of leukotrienes

in the cyclooxygenase pathway the synthesis of prostaglandins and thromboxanes is performed

Answer 435

aspirin is an irreversible inhibitor of the enzyme lipoxygenase

Question 436

Which of the following foods does not supply cholesterol in the human body?
brain
liver
egg yolk
sunflower seeds

Answer 436

sunflower seeds

Question 437

Which of the following enzymes catalyze the hydrolysis of triacylglycerols located in different lipoprotein complexes (eg. in chylomicrons, VLDL)?
lecithin-cholesterol-acyltransferase
lipoprotein lipase
pancreatic lipase
adipolithyc lipase

Answer 437

lipoprotein lipase

Question 438

In which of the following cell compartments, except mitochondria, the oxidation of fatty acids may occur?
cytosol
endoplasmic reticulum
peroxisomes
lysosomes

Answer 438

peroxisomes

Question 439

In which of the following compartments of hepatocytes ketogenesis occurs ?
endoplasmic reticulum
cytosol
lysosomes
mitochondria

Answer 439

mitochondria

Question 440

By which of the following shuttle mechanisms the transfer of activated fatty acids from the cytosol into the mitochondria is performed?
acyl-carnitine
none of the above mentioned
malate-aspartate
glycero phosphate

Answer 440

acyl-carnitine

Question 441

At which positions in the fatty acids’ chains double bonds are introduced in humans ?
5, 8, 11 and 14
4, 5, 6 and 9
Опция 4
4, 5, 8 and 9

Answer 441

4, 5, 8 and 9

Question 442

Which of the following enzymes play an important role in the metabolism of lipoprotein complexes:
1)hepatic lipase
2)pancreatic lipase
3)lipoprotein lipase
4)LCAT (lecithin cholesterol acyltransferase)
3+4
1+2
1+3+4
1+2+3

Answer 442

1+2

Question 443

By which of the following substances the bile acids are conjugated (primary bile acids)?
none of them
glutathione
glucuronic acid
taurine

Answer 443

taurine

Question 444

Which of the following statements about the cholesterol synthesis is wrong?
cholesterol synthesis begins in the cytosol and continues and ends in the endoplasmic reticulum (microsomal fraction)

in the human body a large amount of cholesterol is synthesized in the intestinal mucosal cells
over 50% of the cholesterol in the human body resulted from endogenous synthesis

cholesterol synthesis occurs in the mitochondria

Answer 444

cholesterol synthesis occurs in the mitochondria

Question 445

Which of the following statements about the activation of fatty acids before their inclusion in β-oxidation is wrong?

activation of fatty acids is by connecting them with coenzyme A and turning them into acyl CoA derivatives

activation of the fatty acids takes place in the mitochondrial matrix

long chain fatty acids are activated

activation of the fatty acids takes place in the endoplasmic reticulum

Answer 445

activation of the fatty acids takes place in the endoplasmic reticulum

Question 446

How are the low-density lipoproteins (LDL) are assumed by the cells (entering from the blood into the cells)?
by passive diffusion
by facilitated diffusion
by receptor-mediated endocytosis
by secondary active transport

Answer 446

by receptor-mediated endocytosis

Question 447

In which of the following organs takes place the synthesis of ketone bodies (ketogenesis)?
skeletal muscle
brain
liver
heart muscle

Answer 447

liver

Question 448

Which of the following lipoprotein complexes are the basic carriers of TAG to peripheral tissues:
1)Chylomicrons
2)VLDL
3)LDL
4)HDL
1+2+3
1+2
1+3+4
3+4

Answer 448

1+2

Question 449

Which of the following compounds are not allosteric activators of the main key enzyme in the synthesis of FA, Acetyl CoA carboxylase?
1) acyl-CоА
2)acetyl-CоА
3)malonyl-CоА
4)citrate
1+2+3
2+4
2+3
2+3+4

Answer 449

2+4

Question 450

All of the following fatty acids are synthesized in the human body by the exception of one. Which is it?
palmitic acid
linoleic acid
oleic acid
stearic acid

Answer 450

linoleic acid

Question 451

Which of the following groups of lipids are glycolipids?
1)sphingomyelins
2)gangliosides
3)cerebrosides
4)lecithins
1+2+3
2+3+4
1+4
2+3

Answer 451

2+3

Question 452

1. Which of the following enzymes, involved in the breakdown of carbohydrates in the digestive tract of humans, has/have small intestine origin?
   1) sucrase
   2) glucoamylase
   3) lactase
   4) α- amylase
   a) 1+2+3
   b) 1+3
   c) 2+4
   d) 4

Answer 452

a) 1+2+3

Question 453

3. Which of the following symptoms are typical for mono- and disaccharidases malabsorption (intolerance) and lactose intolerance?
   1) diarrhea
   2) distension the intestine
   3) painful colics
   4) meteorism
   a) 1+2+3
   b) 1+3
   c) 2+4
   d) 1+2+3+4

Answer 453

d) 1+2+3+4

Question 454

5. Which of the following enzymes involved in the glycolysis is the major regulatory enzyme of this pathway:
   a) Phosphofructokinase-2 (PFK-2)
   b) Aldolase
   c) Phosphoglycerate kinase
   d) Phosphofructokinase-1 (PFK-1)

Answer 454

d) Phosphofructokinase-1 (PFK-1)

Question 455

7. In which of the following cells the anaerobic glycolysis is performed:
   1) white muscle fibers (during active contraction)
   2) cells of the renal medulla
   3) erythrocytes
   4) cells of the eye lens
   a) 1+2+3
   b) 1+3
   c) 2+4
   d) 1+2+3+4

Answer 455

d) 1+2+3+4

Question 456

8. Which of the following substances is a direct product of the action of the enzyme glycogen phosphorylase (glycogenolysis):
   a) Glucose-6-phosphate
   b) Glucose
   c) Glucose-1-phosphate
   d) None of the mentioned above

Answer 456

c) Glucose-1-phosphate

Question 457

10. Which of the following enzymes uses NAD.H as coenzyme in reduction process in anaerobic glycolysis:
    a) Pyruvate kinase
    b) Enolase
    c) Lactate dehydrogenase

Answer 457

c) Lactate dehydrogenase

Question 458

11. Which of the following statements about the malate-aspartate shuttle is not true:
    a) The shuttle is bidirectional
    b) Cytoplasmic and mitochondrial malate dehydrogenases participate in the shuttle
    c) The oxidation in the respiratory chain of the two pairs of reducing equivalents transferred by the shuttle mechanism, leads to the synthesis of 4 ATP molecules
    d) The pair of substrates involved in the shuttle are oxaloacetate and malate

Answer 458

c) The oxidation in the respiratory chain of the two pairs of reducing equivalents transferred by the shuttle mechanism, leads to the synthesis of 4 ATP molecules

Question 459

22. Which of the following co-enzymes serve as such of the enzyme of the pentose phosphate pathway, transketolase, and by measuring the enzymatic activity of transketolase is diagnosed a possible deficiency of this vitamin in the body:
    a) pyridoxal phosphate
    b) thiamine pyrophosphate
    c) NADP
    d) FAD

Answer 459

b) thiamine pyrophosphate

Question 460

23. In which of the following types of cells the transport of glucose is insulin-independent:
    1) adipocytes
    2) brain
    3) skeletal muscle cells
    4) erythrocytes
    a) 1+2+3
    b) 1+3
    c) 2+4
    d) None of the above mentioned

Answer 460

c) 2+4

Question 461

24. Which of the following statements about the pentose phosphate pathway in mature erythrocytes is true:
    a) Provides ribose-5-phosphate for the synthesis of nucleotides
    b) Provides NADPH for fatty acid synthesis
    c) Provides NADPH for maintaining the level of reduced glutathione, necessary for the disposal of Н2О2
    d) Provides NADPH of cholesterol synthesis

Answer 461

c) Provides NADPH for maintaining the level of reduced glutathione, necessary for the disposal of Н2О2

Question 462

25. Which of the following statements about the transport of glucose from the blood into the cells of skeletal muscle is wrong:
    a) the transport is carried out by a glucose transporter (facilitated diffusion)
    b) insulin stimulates glucose transport through the export of glucose carriers on the cell membrane, i.e. by increasing the number of transporters on the cell membrane
    c) the glucose enters the cells of the skeletal muscle along the concentration gradient
    d) Insulin induces the biosynthesis of an enzyme which catalyzes phosphorylation of the free glucose to glucose-6-phosphate

Answer 462

d) Insulin induces the biosynthesis of an enzyme which catalyzes phosphorylation of the free glucose to glucose-6-phosphate

Question 463

42. Which of the following statements about the metabolism of liver glycogen is wrong:
    a) it is synthesized after carbohydrate-rich food intake
    b) insulin stimulates its synthesis
    c) it is broken down in conditions with high blood glucose levels
    d) by degradation it provides blood glucose

Answer 463

d) by degradation it provides blood glucose

Question 464

d) phosphoenolpyruvate-carboxykinase (PEPKK)
29. Which of the following hormones stimulates the gluconeogenesis by inducing biosynthesis of phosphoenolpyruvate-carboxykinase (PEPKK) and other specific enzymes of gluconeogenesis:
a) Cortisol
b) Insulin
c) Aldosterone
d) Adenocorticotropic hormone (ACTH)

Answer 464

a) Cortisol

Question 465

46. Which of the following statements about the effects of cortisol on the blood glucose level is correct:
    a) cortisol increases blood glucose level by stimulating the glycogenolysis
    b) cortisol increases blood glucose level by stimulating gluconeogenesis
    c) cortisol decreases blood glucose level by increasing the uptake of glucose into cells
    d) cortisol decreases blood glucose level by stimulating the glycolysis

Answer 465

b) cortisol increases blood glucose level by stimulating gluconeogenesis

Question 465

43. Which of the following statements about the influence of insulin on blood glucose level is wrong:
    a) Insulin reduces the level of blood glucose by accelerating its transport from the blood into insulin-dependent tissues
    b) Insulin stimulates the synthesis of liver and muscle glycogen
    c) Insulin does not stimulate glucose transport in adipose tissue
    d) Insulin stimulates glycolysis in the liver

Answer 465

c) Insulin does not stimulate glucose transport in adipose tissue

Question 466

47. Which of the following statements about the mechanism by which insulin affects the activity of glycogen synthase (regulatory enzyme of glycogenogenesis) is wrong:
    a) insulin decreases the level of cAMP, which leads to dropout of the activation of Protein kinase A, catalyzing the formation of the active phosphorylated form of the protein, called “inhibitor-1”
    b) When the inhibitory protein-1 is inactive (dephosphorylated) it does not inhibit the activity of proteinphosphstase – 1
    c) the active protein phosphatase-1 catalyzes the dephosphorylation of glycogen synthase (glycogen synthase a)
    d) insulin signaling leads to creating of the phosphorylated form of glycogen synthase (glycogen synthase b)

Answer 466

d) insulin signaling leads to creating of the phosphorylated form of glycogen synthase (glycogen synthase b)