Biochemistry

Question 1

About simple lipids we can say:

a) They contain glucose bound by ester bond.
b) They do not contain ester bond.
c) They have hydrophobic properties.
d) They are esters of long-chain fatty acids and glycerol.

Answer 1

c) They have hydrophobic properties.

d) They are esters of long-chain fatty acids and glycerol.

Question 2

Esters of long-chain fatty acids and glycerole:

a) are cleaved in gastrointestinal tract by lipase
b) occur in esters of cholesterol
c) occur also in complex lipids
d) are part of steroids

Answer 2

a) are cleaved in gastrointestinal tract by lipase

c) occur also in complex lipids

Question 3

Alcylglycerols in their molecule can contain components bound:

a) by the phosphoester bond
b) saturated fatty acids and glycerol
c) unsaturated fatty acids and glycerol
d) glucose

Answer 3

b) saturated fatty acids and glycerol

c) unsaturated fatty acids and glycerol

Question 4

Complex lipids are:

a) phospholipids
b) triacylglycerols with different types of carboxylic acids
c) waxes
d) those lipids which are the main components of adipose tissue

Answer 4

a) phospholipids

Question 5

Fatty acids are:

a) amphiphatic
b) equipped with a N- and a C-terminus
c) made by the enzyme fatty-acid-synthase
d) main component of waxes

Answer 5

a) amphiphatic
c) made by the enzyme fatty-acid-synthase
d) main component of waxes

Question 6

In phospholipids:

a) saturated fatty acids are not present
b) glycerol, fatty acids, phosphoric acid and nitrogenous component e.g. choline are present
c) part of molecule is electrically charged (dipole)

d) one part of molecule is hydrophilic and the other is
hydrophobic

Answer 6

b) glycerol, fatty acids, phosphoric acid and nitrogenous component e.g. choline are present
c) part of molecule is electrically charged (dipole)

d) one part of molecule is hydrophilic and the other is
hydrophobic

Question 7

Steroids:

a) belong to complex lipids
b) can be found in cell membrane
c) are the energy storage form of lipids
d) some of them are hormones

Answer 7

b) can be found in cell membrane

d) some of them are hormones

Question 8

Isoprene unit:

a) is building unit of terpenes
b) has the formula – (C5H8)n
c) has the formula -(CH2-CH=CH-CH2)
d) is derived from 2-metyl-1,3butadiene

Answer 8

a) is building unit of terpenes
b) has the formula – (C5H8)n
d) is derived from 2-metyl-1,3butadiene

Question 9

Osmotic lysis of cell occurs:

a) when excess water moves into the cell causing its volume to increase and finally it bursts
b) when an animal cell is placed into distilled water
c) when the cell absorbs water and decreases
d) when an animal cell is placed into a hypertonic environment

Answer 9

a) when excess water moves into the cell causing its volume to increase and finally it bursts
b) when an animal cell is placed into distilled water

Question 10

Sort the following compounds by increasing membrane permeability:

a) ethanol
b) N2
c) H2O
d) Ca2+

Answer 10

1. Ca2+
2. H2O
3. ethanol
4. N2

Question 11

General formula C6H12O6 refers to:

a) glucose
b) arabinose
c) ribose
d) mannose

Answer 11

a) glucose

d) mannose

Question 12

Fructose is:

a) compound soluble in polar solvents
b) polyhydroxyaldehyde
c) polyhydroxyketone
d) substrate for synthesis of saccharose

Answer 12

a) compound soluble in polar solvents
c) polyhydroxyketone
d) substrate for synthesis of saccharose

Question 13

Ring structure with one O-atom and 4 C-atoms. Two C-atoms have one OH group. One C-atom left to the O-atom has CH2OH. One C-atom right to the O-atom has CH2OH and OH.

a) glucose
b) fructose
c) pyranose
d) furanose

Answer 13

b) fructose

d) furanose

Question 14

Cyclic form of monosaccharides is:

a) ester
b) acetal
c) hemiacetal
d) part of steroids

Answer 14

c) hemiacetal

Question 15

Benedict’s reagent is a chemical solution that is taken for the detection of:

a) aldoses
b) ketoses
c) glycogen production
d) glucosuria

Answer 15

a) aldoses

d) glucosuria

Question 16

Glycogen is:

a) is branched
b) animal version of starch
c) consists of glucoses
d) contains 1,4- and 1,6-glycosidic bonds

Answer 16

a) is branched
b) animal version of starch
c) consists of glucoses
d) contains 1,4- and 1,6-glycosidic bonds

Question 17

Molecule of starch is formed:

a) by esterification
b) by polycondensation
c) by phosphorylation
d) by hydrolysis

Answer 17

b) by polycondensation

Question 18

β-O-glycosidic bond is present in molecule of:

a) mannose
b) cellulose
c) starch
d) maltose

Answer 18

b) cellulose

Question 19

In living systems saccharides can be covalently linked to:

a) nucleic acids
b) lipids
c) proteins
d) none of the molecules listed above

Answer 19

b) lipids

c) proteins

Question 20

General formula (C6 H10 O5)n refers to:

a) aldopentoses
b) lactose
c) disaccharides
d) starch

Answer 20

d) starch

Question 21

Basic building units of proteins are connected by bond:

a) which is not cleaved by denaturation
b) which belongs to covalent bonds
c) hydrogen
d) disulphide

Answer 21

a) which is not cleaved by denaturation

b) which belongs to covalent bonds

Question 22

Denaturation of proteins can be induced by:

a) proteases
b) changes in pH
c) heat
d) radicals

Answer 22

b) changes in pH
c) heat
d) radicals

Question 23

Basic building units of proteins are:

a) neutral amino acids, e.g. aspartic acid
b) 2-amino carboxylic acids
c) alpha-amino acids
d) substitution derivatives of carboxylic acids (with –NH2 group bound to alpha carbon atom)

Answer 23

b) 2-amino carboxylic acids
c) alpha-amino acids
d) substitution derivatives of carboxylic acids (with –NH2 group bound to alpha carbon atom)

Question 24

Important functions of proteins in organisms are:

a) catalysis
b) binding of compounds
c) energy storage
d) providing structure

Answer 24

a) catalysis
b) binding of compounds
d) providing structure

Question 25

Which amino acid is not proteinogenic:

a) Tryptophane
b) Tyrosin
c) Tyroxine
d) Selenocysteine

Answer 25

c) Tyroxine

Question 26

Enzymes:

a) are biocatalysts
b) are proteins
c) are macromolecules composed of amino acids connected by ester bond
d) are located always in extracellular space

Answer 26

a) are biocatalysts

b) are proteins

Question 27

What is responsible for substrate specificity of enzyme reaction:

a) apoenzyme
b) coenzyme
c) pH-optimum
d) decrease of activation energy

Answer 27

a) apoenzyme

c) pH-optimum

Question 28

Compound A is substrate of enzyme E. Addition of structurally related compound B leads to an increase of Km by 3, while Vmax remains the same. This effect is a(n)

a) allosteric activation
b) non-reversible inhibition
c) non-competitive inhibition
d) competitive inhibition

Answer 28

d) competitive inhibition

Question 29

Which compound shows a peptide bond:

There are 4 bonds shown, but to be able to answer the question:

What is a peptide bond?

Answer 29

O
I I
C - NH

Question 30

Which of the following statements about enzymes is/are wrong:

a) enzymes react just with specific substrates

b) enzymes act by lowering activation energy of
substrate

c) enzymes that act in concert are called coenzymes
d) enzymes stabilize transition state of reactants.

Answer 30

c) enzymes that act in concert are called coenzymes

Question 31

A stepwise oxidation is more favorable than direct burning of sugars in cells, because

a) activation energy is lower;
b) small portions of energy can be easier controlled;
c) released energy can be stored in carrier proteins;

d) energy is released as heat and thus supports other
biochemical reactions ins cell.

Answer 31

a) activation energy is lower;
b) small portions of energy can be easier controlled;
c) released energy can be stored in carrier proteins;

Question 32

The oxidative degradation of organic substances is known as:

a) catabolism
b) metabolism
c) anabolism
d) reduction

Answer 32

a) catabolism

Question 33

Oxidation of organic molecules usually results in the release of

a) a hydroxyl ion
b) 2e- and2H+
c) CO2 and H2O
d) Acetyl-CoA

!!! Question in class was:
Oxidation of organic molecules usually result in the direct release of!!!

Answer 33

If question with “direct”:
b) 2e- and 2H+

If question without “direct”:

b) 2e- and 2H+
c) CO2 and H2O

Question 34

Acetyl-CoA is an activated carrier of

a) Phosphate
b) Methyl group
c) Carboxyl group
d) Acetyl group

Answer 34

d) Acetyl group

Question 35

Glycolysis is the process by which one molecule of glucose is degraded into

a) two molecules of lactat
b) two molecules of pyruvate
c) two molecules of ATP
d) two molecules of 2-oxopropanate

Answer 35

b) two molecules of pyruvate

d) two molecules of 2-oxopropanate

Question 36

The net energy outcome of glycolysis is

a) 2 acetyl-CoA
b) 2 NADH
c) 2 ATP
d) 2 ATP and 2 NADH

Answer 36

d) 2 ATP and 2 NADH

Question 37

The net outcome of the citrate-cycle is
a) 3 NADH, 1GTP, 1 FADH2, release of 2 H2O

b) 2NADH and 2ATP
c) 3 NADPH, 1GTP, 1 FADH2, release of 2 CO2
d) 3 NADH, 1GTP, 1 FADH2, release of 2 CO2

Answer 37

d) 3 NADH, 1GTP, 1 FADH2, release of 2 CO2

Question 38

In ß-oxydation of fatty acids
fatty acyl-CoA gets shortened each cycle by
how many carbons?
a)  1 
b) 2
c)  3 
d)  4

Answer 38

b) 2

Question 39

Which equation represents the reaction catalyzed by ATP synthase?

a) ATP –> ADP + Pi + H2O
b) ATP + H2O –> ADP + Pi
c) ADP + Pi –> ATP + H2O
d) ADP + Pi + H2O –> ATP

Answer 39

c) ADP + Pi –> ATP + H2O

Question 40

Proteins of the respiratory chain are

a) Ubiquinone
b) NADH dehydrogenase
c) Cytochrome c
d) Cytochrome oxidase

Answer 40

a) Ubiquinone
b) NADH dehydrogenase
c) Cytochrome c
d) Cytochrome oxidase

Question 41

Mitochondria are the organelles
in which the following processes occur:
a)  oxidative phosphorylation
b)  glycolysis
c)  citric acid cycle
d)  ß-oxidation of fatty acids

Answer 41

a) oxidative phosphorylation
c) citric acid cycle
d) ß-oxidation of fatty acids

Question 42

ATP molecule contains:

a) adenine base
b) macroergic bonds
c) phosphoanhydrid bonds
d) glucose

Answer 42

a) adenine base
b) macroergic bonds
c) phosphoanhydrid bonds