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Biochemisty Main > 3rd Biochemistry Lecture Exam (Batch 2024) > Flashcards

3rd Biochemistry Lecture Exam (Batch 2024) Flashcards

1
Q

1.Which of the following is a common nitrogen acceptor for all reactions involving transamination?

A. α-ketoglutarate
B. Pyruvate
C. Oxaloacetate
D. Acetoacetate

A

A. α-ketoglutarate

The most common compounds involved as a donor/acceptor pair in transamination reactions are glutamate and α-ketoglutarate (2-oxoglutarate), which participate in reactions with many different aminotransferases.

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2
Q
  1. Which of the following molecules in NOT synthesized from Cysteine?

A. Taurine
B. Mercaptoethanolamine
C. Melanin
D. Pyruvate.

A

C. Melanin

Melanin is form tyrosine

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3
Q
  1. Which of the following amino acids is NOT a donor of one carbon compound?

A. Histidine
B. Tyrosine
C. Tryptophan
D. Serine

A

B. Tyrosine

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4
Q
  1. In mammalian cells, Ser can be a biosynthetic substrate for the synthesis of what amino acid?​

A. Methionine
B. Lysine
C. Arginine
D. Glycine

A

D. Glycine

Precursor of Glycine is Serine

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5
Q
  1. Which is the coenzyme utilized in the synthesis of serine from glycine?

A. N5N10 methylene tetrahydrofolate
B. Tetrahydrofolate
C. Formyl tetrahydrofolate
D. Methyl tetrahydrofolate

A

A. N5N10 methylene tetrahydrofolate

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6
Q
  1. Dopamine is synthesized from which of the amino acids named:

A. Tyrosine
B. Tryptophan
C. Histidine
D. Methionine

A

A. Tyrosine (also epinephrine and norepinephrine)

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7
Q
  1. Transamination reactions require what coenzyme derived from what vitamin?

A.NAD+/Vitamin B3
B.FAD/Vitamin B2
C.Pyridoxal PO4/Vitamin B6
D.Cobalamin/Vitamin B12

A

C.Pyridoxal PO4/Vitamin B6

The chirality of an amino acid is determined during transamination. For the reaction to complete, aminotransferases require participation of aldehyde containing coenzyme, pyridoxal-5’-phosphate (PLP), a derivative of Pyridoxine (Vitamin B6).

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8
Q
  1. Histidine is degraded to α-ketoglutarate and is described as a:

A. Glucogenic amino acid
B. Glucogenic/ketogenic amino acid
C. Ketogenic amino acid
D. None of the choices

A

A. Glucogenic amino acid

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9
Q
  1. A person with phenylketonuria cannot convert:​

A. Phenylalanine to isoleucine
B. Phenylalanine to tyrosine
C. Phenol into ketones
D. Phenylalanine to phenylpyruvate

A

B. Phenylalanine to tyrosine

Tyrosine, which is normally formed from phenylalanine by PAH, is deficient

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10
Q
  1. An example of a transamination reaction is:

A. Glutamate = hexanoic acid + NH3
B. Aspartate + hexanoic acid = glutamate + oxaloacetate
C. Aspartate + α-ketoglutarate = glutamate + oxaloacetate
D. Glutamate = α-ketoglutarate + NH3

A

C. Aspartate + α-ketoglutarate = glutamate + oxaloacetate

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11
Q
  1. A person with phenylketonuria is advised not to consume which of the following products?​

A. Glycine containing products
B. Glucose
C. Fat containing foods
D. Aspartame

A

D. Aspartame

Aspartame sweetener becomes aspartic acid and phenylalanine during digestion

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12
Q
  1. Tyrosine upon degradation gives rise to acetoacetyl CoA and fumarate, therefore characterized as:​

A. Glucogenic amino acid
B. Ketogenic amino acid
C. Both glucogenic/ketogenic amino acid
D. Essential amino acid”​

A

C. Both glucogenic/ketogenic amino acid
WIFTY

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13
Q
  1. Leucine degradation generates acetoacetate, and as such is characterized as:

A.Glucogenic amino acid
B.Ketogenic amino acid
C.Both glucogenic/ketogenic amino acid
D.Essential amino acid​

A

B.Ketogenic amino acid
LL

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14
Q
  1. Which metabolic abnormality gives rise to the serious disease phenylketonuria?

A. Homocysteine cannot be converted into methionine
B. Phenylalanine cannot be converted into tyrosine
C. Phenylalanine cannot be converted into alanine
D. Tyrosine cannot be converted into phenylalanine

A

B. Phenylalanine cannot be converted into tyrosine

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15
Q
  1. In Maple Syrup Urine Disease, the enzyme deficient is?​

A. alpha keto acid dehydrogenase
B. Pyridoxal phosphate
C.Transaminase
D. Alkaptonuria

A

A. alpha keto acid dehydrogenase

The biochemical defect in MSUD involves the alpha ketoacid decarboxylase complex. Harper’s page 721

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16
Q
  1. A mutation affecting the gene that codes for the enzyme homogentisic acid oxidase results to a clinical condition known as:

A. Tyrosinemia Type I
B. Richner-Hanhart syndrome
C. Tyrosinemia Type II
D. Alkaptonuria

A

D. Alkaptonuria

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17
Q
  1. Tyrosinemia Type I is due to a deficiency of which enzyme?

A. Fumarylacetoacetate hydrolase
B. Phenylalanine hydrolase
C. Cystathionine β-synthase
D. Homogentisate oxidaseb.

A

A. Fumarylacetoacetate hydrolase

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18
Q
  1. Which of the following amino acids are used to synthesize the donor of methyl groups in methylation reactions?

A. Cy
B. Met
C. Ser
D. Ala

A

B. Met

Methionine is an indispensable amino acid that is required for protein synthesis, and its adenosylated product S-adenosylmethionine plays a key role in whole-body metabolism because it is the primary biological methyl donor for the synthesis of >50 metabolites and methylation reactions

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19
Q
  1. What is the fate of the SO42- (sulfate) generated in the metabolism of cysteine?

A. Incorporated into other substances
B. Liberated unchanged
C. Used in the synthesis of PAPS
D. Incorporated into glucose to form cerebrosides

A

C. Used in the synthesis of PAPS

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20
Q
  1. The amino acid upon action of nitric oxide synthase (NOS) gives rise to NO, an endothelial relaxing factor.​

A. Asn
B. Lys
C. Asp
D. Arg

A

D. Arg

Arginine, together with L-Citrulin,e gives rise to Nitric Oxide, in a reaction catalyzd by nitric oxide synthase. Trans 2023, LE3.03, page 1.

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21
Q
  1. Histamine, an intermediate of histidine metabolism during an allergic reaction is synthesized by mast cells through what
    reaction?

A. Decarboxylation
B. Reduction
C. Oxidation
D. Hydroxylation​

A

A. Decarboxylation

Histamine, an intermediate of histidine metabolism during an allergic reaction is synthesized by mast cells through Decarboxylation reaction

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22
Q
  1. Removal of carboxylic group from glutamate generates a neurotransmitter known as:​

A. Serotonin
B. Dopamine
C. y–amino butyric acid (GABA)
D. Neurotensin

A

C. y–amino butyric acid (GABA)

Trans 2023 #3.03 p.6
* γ-Aminobutyrate (GABA) functions in brain tissue
as an inhibitory neurotransmitter by altering
transmembrane potential differences.
* GABA is formed by decarboxylation of glutamate
by l-glutamate decarboxylase

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23
Q
  1. Adrenaline is synthesized from tyrosine, utilizing norepinephrine through a methylation reaction requiring;​

A.S-adenosyl methionine
B.Methyl cobalamin
C.3’-phosphoadenosine-5’-phosphosulfate
D.5-deoxyadenosyl cobalamin

A

A.S-adenosyl methionine

S-Adenosyl methionine (SAM-e) is a common cosubstrate involved in methyl group transfers, transsulfuration, and aminopropylation. Although these anabolic reactions occur throughout the body, most SAM-e is produced and consumed in the liver.​

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24
Q
  1. What is the source of the amino group added to aspartate to synthesize asparagine?

A. Glutamine
B. Ammonia
C. Glycine
D. Tyrosine

A

A. Glutamine

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25
Q
  1. Which amino acid whose carbons upon degradation give rise to fumarate?​

A. Aspartate
B. Methionine
C. Glutamine
D. Arginine​

A

A. Aspartate

The amino acid whose carbons upon degradation gthat give rise to fumarate is Aspartate.

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26
Q
  1. In glycogen, the amylose chains are formed by what kind of glycosidic​

A. Alpha 1,4
B. Beta 1,4
C. Alpha 1,2
D. Beta 1,3

A

A. Alpha 1,4

Amylopectin is Alpha 1,4 & Alpha 1,6

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27
Q
  1. This glycosidic bond creates the branching part of amylopectin chains of glycogen​

A.Alpha 1,4
B. Beta 1.4
C.Alpha 1,2
D.Beta 1,3

A

A.Alpha 1,4

Amylase Alpha 1,4
Amylopectin Alpha 1,4 and Alpha 1,6

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28
Q
  1. What is the key regulatory enzyme used in glycogenolysis by the cells?

A. Glycogen phosphorylase kinase
B. Amylo α-1,4 to α-1,4 glucan transferase
C. α-1,6 glucosidase
D. glycogen phosphorylase

A

D. glycogen phosphorylase

Glycogenolysis is the biochemical pathway in which glycogen breaks down into glucose ` phosphate and glycogen. the reaction takes place in the hepatocytes and myocytes. the process is under the regulation of 2 key enzyme: phosphorylase kinase and glycogen phosphorylase​

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29
Q
  1. Glycogen phosphorylase degrades glycogen during times of fasting starting at

A. Reducing end at anomeric carbon
B. Non-reducing end at C4
C. Sixth carbon having the alcohol group
D. Branches having the alpha-1,6 glycosidic bond

A

B. Non-reducing end at C4

Glycogen phosphorylase sequentially cleaves the α(1→4) glycosidic bonds between the glucosyl residues at the nonreducing ends of the glycogen chains by simple phosphorolysis (producing glucose 1-phosphate) until four
glucosyl units remain on each chain before a branch point

(Lippincott’s 6th ed., Chapter 11)

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30
Q
  1. Muscle glycogen phosphorylase is allosterically modified by these factors EXCEPT:

A. ATP
B. AMP
C. Glucose
D. Glucose 6-PO4

A

B. AMP

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31
Q
  1. What is the key regulatory enzyme used in glycogenesis by the cells?​

A. Glycogen synthase kinase
B. Glycogen synthase
C. Amylo α-1,4 to α-1,4 glucan transferase
D. Amylo α-1,4 to α-1,6 glucan transferase

A

B. Glycogen synthase

Glycogen synthase is the principal enzyme that synthesizes glycogen. Activation of Glycogen Synthase simulates
Glycogenesis

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32
Q
  1. What is the important amino acid
    residue of glycogenin that is used to initiate the synthesis of glycogen

A. Tyrosine
B. Lysine
C. Aspartate
D. Glutamine

A

A. Tyrosine

The protein, named glycogenin, is joined to muscle glycogen via a novel linkage involving the hydroxyl group of tyrosine, a fact of possible significance in the light of insulin’s message being transmitted by tyrosine phosphorylation.

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33
Q
  1. What is the hormone that should be in high levels in the system so that glycogenesis will be stimulated?

a. Epinephrine
b. Glucagon
c. Insulin
d. Adrenaline

A

c. Insulin

First, it activates the enzyme hexokinase, which phosphorylates glucose, trapping it within the cell. Insulin acts to inhibit the activity of glucose-6 phosphatase. It also activates several of the enzymes that are directly involved in glycogen synthesis, including phosphofructokinase and glycogen synthase.

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34
Q
  1. What are the two hormones that should be in high levels in the system so that glycogenolysis will be stimulated?

A. Epinephrine/glucagon
B. Adrenaline/estradiol
C. Insulin/glucagon
D. Epinephrine/insulin

A

A. Epinephrine/glucagon

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35
Q
  1. In the muscles, glycogen phosphorylase is transformed into the active enzyme directly by:
    A. Glycogen synthase kinase
    B. Protein kinase A
    C. Phosphorylase kinase
    D. Adenylate kinase
A

B. Protein kinase A

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36
Q

36.The active form of glycogen synthase is ______.​

A. Phosphorylated
B. The tense state
C. With attached PO4 group
D. Dephosphorylated

A

D. Dephosphorylated

Phosphorylation catalyzed by protein Kinases.
Dephosphorylation catalyzed by protein Phosphatases.

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37
Q
  1. The active form of glycogen phosphorylase is _____.

A. Phosphorylated
B. The tense state
C. Without attached PO4 group
D. Dephosphorylated

A

A. Phosphorylated

Glycogen phosphorylase exists in an inactive, dephosphorylated form and in active, phosphorylated form

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38
Q
  1. In the muscles, the need for calcium and energy used for muscle contraction is coordinated by this enzyme;

A. Glycogen phosphorylase
B. Glycogen synthase kinase
C. Glycogen phosphorylase kinase
D. α-1,6 glucosidase

A

A. Glycogen phosphorylase

Muscle glycogen phosphorylase is present to degrade glycogen to forms of energy by means of glycolysis during muscle contractions

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39
Q
  1. When is glycogen phosphorylase kinase fully activated?

A. β subunit bound to Ca2+ & α subunit phosphorylated
B. β subunit bound to Ca2+ & α subunit phosphorylated
C. β subunit phosphorylated & Δ subunit bound to Ca2+
D. γ subunit phosphorylated & β subunit bound to Ca2+

A

C. β subunit phosphorylated & Δ subunit bound to Ca2+

The phosphorylase kinase is completely activated when the β and α subunits are phosphorylated by protein kinase A and the delta subunit has bound to calcium ions.

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40
Q
  1. The reaction catalysed by glycogen phosphorylase is carried out with the help of what ion?

A.Calcium
B. Hydroxyl ions
C. Hydrogen ions
D. Inorganic PO4-

A

A.Calcium

Calcium ion is carried out by the reaction catalysed by glycogen phosphorylation. (Harpers 30th Ed page 146)

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41
Q
  1. What is the reason why glycogen stored and utilized for energy needs of the cells is a branched glucose polymer?

A. More non-reducing ends for faster breakdown
B. More reducing ends for faster synthesis
C. Increasing the insolubility of the molecule
D. Decreasing the solubility of the polymer

A

B. More reducing ends for faster synthesis

Branching increases number of nonreducing ends to which new glucosyl residues are added. - Accelerates rate of glycogen synthesis.

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42
Q
  1. The product of the action of glycogen phosphorylase;

A. Glucose 6-PO4
B. Fructose 1-PO4
C. Free glucose
D. Glucose 1-PO4

A

D. Glucose 1-PO4

The activated glycogen Phosphorylase now catalyzes the breakdown of glycogen, releasing Glucose-1-Phosphate

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43
Q
  1. What is the main function of the degradation of glycogen in the liver?

a. To supply of energy to the liver cells
b. To maintain the level of blood glucose normal
c. To export glucose to the muscle tissue
d. To solely supply the brain with the source of energy

A

b. To maintain the level of blood glucose normal

Glycogenolysis, process by which glycogen, the primary carbohydrate stored in the liver and muscle cells of animals, is broken down into glucose to provide immediate energy and to maintain blood glucose levels during fasting.

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44
Q
  1. The activity of glycogen phosphorylase stops when there are how many glucosyl units from an α-1,6 glycosidic bond?
    A. Two
    B. Three
    C. Four
    D. Six
A

C. Four

The efficient breakdown of glycogen to provide glucose 6-phosphate for further metabolism requires four enzyme activities: one to degrade glycogen, two to remodel glycogen so that it remains a substrate for degradation, and one to convert the product of glycogen breakdown into a form suitable for further metabolism.

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45
Q
  1. When the activity of glycogen phosphorylase stops near a branching point in glycogen, what polymer of glucose is formed?

A. Amylose
B. Amylopectin
C. Maltodextrin
D. Limit dextrin

A

D. Limit dextrin

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46
Q
  1. What is the enzyme activated when insulin predominates in the human system that removes the phosphate groups attached to proteins after the action of glucagon?

A. Phosphodiesterase
B. Protein phosphatase
C. Adenylyl cyclase
D. Phosphatase kinase

A

A. Phosphodiesterase

Phosphodiesterase act on cyclic AMP (cAMP) to transform it to 5’ AMP.

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47
Q
  1. The product of glycogen breakdown in the muscle cells can’t be used by other tissues like the brain for its energy needs because of the absence of what enzyme?

A.Glucos-6-phosphatase
B.Pyruvate carboxylase
C.Glucokinase
D.PEP carboxykinase

A

A.Glucos-6-phosphatase

Glucose-6-phosphatase is absent from most other tissues, consequently is retained for the generation of ATP. (Berg JM, Tymoczko JL, Strer L., Section 21.1.4 ,Biochemistry. 5th ed., 2002)

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48
Q
  1. An infant was brought to the emergency room after the parents witnessed her having seizures. The child’s blood glucose was 28 mmol/L. After a thorough workup, a glycogen storage disease (GSD) was suspected, and a muscle biopsy was significant for the accumulation of dextrin, a form of glycogen with branching limited to only a few glucose molecules. Which of the following GSD is most likely the cause of hypoglycaemia and subsequent seizures?

A. Type I – von Gierke’s disease
B. Type II – Pompe’s disease
C. Type III – Cori’s disease
D. Type IV – Andersen’s disease

A

D. Type IV – Andersen’s disease

Andersen’s Disease is a Glycogen storage disease Type IV. It is deficient in Branching enzyme. (Trans 3.03 Page 7)

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49
Q
  1. 28 mmol/L. After a thorough workup, a glycogen storage disease (GSD) was suspected, and a muscle biopsy was significant

a. Pompe’s
b. von Gierke’s
c. Anderson’s
d. Her’s

A

b. von Gierke’s

Von Gierke disease - Glycogen accumulation in liver and renal tubule cells; hypoglycemia; lactic acidemia; ketosis; hyperlipemia. Enzyme deficient: Glucose-6-phosphatase. Reference: Harper’s 30th ed. Table 18-2 Page 179 - Glycogen storage Diseases

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50
Q
  1. For the accumulation of dextrin, a form of glycogen with branching limited to only a few glucose molecules. Which of the

A. Glycogen phosphorylase, liver
B. Debranching enzyme, liver
C. Glycogen phosphorylase, muscle
D. Debranching enzyme, muscle

A

C. Glycogen phosphorylase, muscle

Myophosphorylase deficiency, McArdle syndrome - Poor exercise tolerance; muscle glycogen abnormally high (2.5%-4%); blood lactate very low after exercise. Enzyme Deficiency: Muscle phosphorylase Reference: Harper’s 30th ed. Table 18-2 Page 179 - Glycogen storage Diseases

51
Q
  1. following GSD is most likely the cause of hypoglycaemia and subsequent seizures?

A. Glyceraldehyde
B. Erythrose
C. Dihydroxyacetone
D. Glucose

A

A. Glyceraldehyde

“… three carbon sugar glycerose (glyceraldehyde)” & “The Pentose phosphate pathway… two molecules of glyceraldehyde-3phosphate can regenerate glucose-6 phosphate, the pathway can account for the complete oxidation of glucose.” Reference: Harper’s 31st ed. Page 367 & 453

52
Q
  1. The monosaccharides glucose and fructose linked by glycosidic bonds form which sugar;

A. Lactose
B. Maltose
C. Sucrose
D. Fructose

A

C. Sucrose

Hydrolysis of sucrose yields a mixture of glucose and fructose called ““invert sugar”” because fructose is strongly levorotatory and changes (inverts) the weaker dextrorotatory action of sucrose. Reference: Harper’s 30th ed. Page 156 & Trans 2023 #3.05 p.6”

53
Q
  1. This sugar derivative is vital in the synthesis of collagen.

A.Glucuronic acid
B.Hyaluronic acid
C.Ascorbic acid
D.Sorbitol

A

C.Ascorbic acid

54
Q
  1. Major storage form of energy in the body.

A. Glycogen
B. Glucose
C. Cellulose
D. Starch

A

A. Glycogen

Glycogen is the major storage carbohydrate in animals, corresponding to starch in plants (Harper’s 30th edition, page 176)

55
Q
  1. Digestion in the mouth starts with this enzyme cleaving the bonds of dietary starch and glycogen in a random manner
    requiring an optimum pH.

A. Ptyalin
B. Maltotriose
C. Dextrin
D. Isomaltase

A

A. Ptyalin

56
Q
  1. Absence of this enzyme causes dietary cellulose to remain undigested

A.Glucoamylase
B. Sucroamylase
C. Lactase B-glycosidase
D. Trehalase

A

D. Trehalase

located in the brush borders of SI, Trans 2023 #3.05 p.8

57
Q
  1. Cataract formation in diabetes is brought about by accumulation of sorbitol in the lens. This is secondary to interaction
    between blood glucose and;

A. NADPH-dependent aldose reductase
B. Glucokinase
C. Hexokinase
D. Phosphoglucoisomerase

A

A. NADPH-dependent aldose reductase

58
Q
  1. Glucose is maintained in the blood as the sole energy source for the _____ in the non-starving state and as an available
    energy source for all other tissues.

A. Liver
B. Brain
C. Lungs
D. Kidneys

A

B. Brain

59
Q
  1. Special type of isomerism found in structures that are mirror images of each other; vast majority in humans are D-sugars.

A. Epimers
B. Enantiomers
C. Stereoisomers
D. Anomers

A

B. Enantiomers

60
Q
  1. This is the transport system for fructose and mannose involving formation of an intermediate complex with a specific carrier protein.

A.Simple diffusion
B.Facilitated diffusion
C.Active transport
D.Passive transport

A

B.Facilitated diffusion

Fructose is taken up by facilitated diffusion through glucose transporter

61
Q
  1. The carbonyl carbon, either aldehyde or keto group, undergo this process to produce a new alcohol group. Fructose goes through this process to form sorbitol and mannitol.

A. Oxidation
B. Reduction
C. Mutarotation
D. Conformation

A

A. Oxidation

A sugar is classified as a reducing sugar only if it has an open-chain form with an aldehyde group or a free hemiacetal group

62
Q

Which of the following is correct?

A. The Fischer projection is the representation of the cyclic sugar where carbon 1 is the farthest to the right, the plane of the ring is flat
B. Glycogen is synthesized from β-D-glucopyranose
C. The noncarbohydrate portion of the complex carbohydrate molecule is called the aglycone
D. Lactose and sucrose are both reducing sugars

A

C. The noncarbohydrate portion of the complex carbohydrate molecule is called the aglycone

a. The first carbon (C1) is at the top
b. Cellulose from β-D-glucopyranose.
c. Glucose from α- D glucopyranose
d. Sucrose is a non-reducing sugar

63
Q
  1. Which among these tissues depend on the hormone insulin for glucose uptake?

A. Muscles
B. Intestines
C. Hepatocytes
D. Erythrocytes

A

A. Muscles

64
Q
  1. These glucose transporters are found in the liver and pancreas assuring the rapid entry of glucose exhibiting a very high Km?

A. Glut 1
B. Glut 2
C. Glut 3
D. Glut 4

A

B. Glut 2

Glucose Transporters:
GLUT-1 is abundant in erythrocytes and brain
GLUT-2 is found in liver(hepatocytes) and the β cells of the pancreas.
GLUT-3 is the primary glucose transporter in neurons
GLUT-4 (which is insulin-dependent) is found in muscle and adipose tissue
GLUT-5 is the primary transporter for fructose (instead of glucose) in the small intestine and the testes.
(P106 – Lippincott)

65
Q
  1. An athlete has been training for an upcoming triathlon. His coach recommended a high carb diet after the work out to ensure muscle glycogen storage. Activity of glycogen synthase in the resting muscles is increased by the action of;

A. Fasting
B. Glucagon
C. Epinephrine
D. Insulin

A

D. Insulin

When blood glucose levels are high, insulin will stimulate the synthesis of glycogen.

66
Q
  1. In the pentose phosphate pathway, the major products are;

A. Ribulose and ATP
B. Ribulose and NADP
C. Ribulose and NADPH
D. ATP & NADP

A

C. Ribulose and NADPH

The pentose phosphate pathway (also called the hexose monophos-phate pathway, or 6-phosphogluconate pathway) occurs in the cytosolof the cell. It includes two, irreversible oxidative reactions, followed by aseries of reversible sugar–phosphate interconversions (Figure 13.1). NoATP is directly consumed or produced in the cycle. Carbon 1 of glucose6-phosphate is released as CO2, and two NADPH are produced foreach glucose 6-phosphate molecule entering the oxidative part of thepathway. The rate and direction of the reversible reactions of thepentose phosphate pathway are determined by the supply of anddemand for intermediates of the cycle. The pathway provides a majorportion of the body’s NADPH, which functions as a biochemical reduc-tant. It also produces ribose 5-phosphate, required for the biosynthesisof nucleotides (see p. 293), and provides a mechanism for themetabolic use of five-carbon sugars obtained from the diet or the degra-dation of structural carbohydrates in the body (Lippincott’s 5th ed, chapter 13 pp.145-146)

67
Q
  1. Deficiency with this enzyme is associated with crampy abdominal pain and passage of loose, watery stools after significant intake of dairy product.

A. Sucrose
B. Maltase
C. Lactase
D. Galactose

A

C. Lactase

68
Q
  1. Pancreatic enzymes have an absolute requirement for these ions once carbohydration digestion resumes in the lumen of the small intestines.

A. Sodium
B. Chloride
C. Bicarbonate
D. Calcium

A

C. Bicarbonate

69
Q
  1. LX, a 23-year old medical student came in to the OPD with bloating and passage of loose watery stools. On PE, he was
    tachycardic & afebrile with sunken eyeballs and dry lips. LX claimed that he had prior episodes of the same symptoms after
    ingestion of dairy products. This can be due to a deficiency in;

A. Isomaltase
B. Pancreatic amylase
C. Lactase
D. Salivary amylase

A

C. Lactase

70
Q
  1. Compounds having the same structural formula but differing in configuration around one carbon atom are

A.Epimers
B.Enantiomers
C.Stereoisomers
D.Optical isomers

A

A.Epimers

71
Q
  1. The polysaccharide found in the cell wall of insects are;

A. Cellulose
B. Hyaluronic acid
C. Chitin
D. Starch

A

C. Chitin

72
Q
  1. A 10-year old female was brought to the emergency room secondary to alterations in behaviour. On lab exam, ketones are found in her urine. Which of the following is the most likely source of ketones?

A. Glycogenolysis
B. Glycolysis
C. Gluconeogenesis
D. Fatty acid breakdown

A

D. Fatty acid breakdown

73
Q
  1. Aldose reductase is an enzyme abundant in the following tissues except;

A. Liver
B. Nerve tissue
C. Seminal vesicles
D. Muscles

A

D. Muscles

74
Q
  1. Which of the following compounds is not produced from dietary starch by salivary a-amylase?

A. Fructose
B. Maltose
C. Isomaltose
D. Maltotriose

A

A. Fructose

75
Q
  1. Which of the following is an essential finding in fetal erythroblastosis?

A. Cyanosis
B. Hepatomegaly
C. Splenomegaly
D. Renal failure”

A

C. Splenomegaly

76
Q

77.Which of the following statements is correct?

A.Haemolytic disease of the newborn secondary to Rh incompatibility is very common among firstborns
B.Hemolysin in mothers of neonates with Rh incompatibility is frequently absent
C.Spherocytosis is usually negative among patients with ABO incompatibility
D.Reticulocytosis is usually mild in ABO incompatibility

A

D.Reticulocytosis is usually mild in ABO incompatibility

77
Q
  1. Which of the following statements is correct?

A. Rh incompatibility mostly occurs exclusively in infants of blood group A or B born to O mothers
B. IgM Anti-A, Anti-B occur more commonly in O group than group A or B individuals
C. An ABO incompatible mating in which father is O, mother is AB; may produce a compatible O or an incompatible A fetus
D. ABO incompatibility may lead to fetal hemolysis in the first pregnancy because of pre-existing antibodies in mother from infancy

A

D. ABO incompatibility may lead to fetal hemolysis in the first pregnancy because of pre-existing antibodies in mother from infancy

78
Q
  1. Mothers with this blood type have a higher likelihood to have a spontaneous abortion form maternal fetal ABO incompatibility

a. A
b. B
c. AB
d. O

A

d. O

79
Q
  1. Weak/low avidity antibodies were found to cause ABO discrepancies. To resolve weak or missing antibodies, how long was the recommended incubation of serum testing at room temperature to enhance antibody reactions?

a. 5 minutes
b. 10 minutes
c. 15 minutes
d. 30 minutes

A

c. 15 minutes

80
Q
  1. Hydrolysis of lactose yields;

A. Galactose and glucose
B. Galactose and fructose
C. Glucose and fructose
D. Fructose and galactose

A

A. Galactose and glucose

81
Q
  1. Minimum number of carbons required for a monosaccharide
    A. 1
    B. 2
    C. 3
    D. 4
A

C. 3

82
Q
  1. Glycosidic bonds;

A. Connect sugar molecules in both linear and branches of complex carbohydrates
B. Only connect carbon 1 of one sugar to carbon 4 of another
C. Destroy the asymmetric character of the participating carbons
D. Only connect carbon 1 of one sugar and carbon 6 of another

A

A. Connect sugar molecules in both linear and branches of complex carbohydrates

83
Q
  1. Choose the keto triose;

A. Glyceraldehyde
B. Erythrose
C. Dihydroxyacetone
D. Arabinose

A

C. Dihydroxyacetone

84
Q
  1. Carbohydrates are;

A. Polyhydroxy aldehydes and phenols
B. Polyhydroxy aldehydes and ketones
C. Polyhydroxy phenols and ketones
D. Polyhydroxy phenols and alcohols

A

B. Polyhydroxy aldehydes and ketones

85
Q
  1. Presence of carbon monoxide poisoning results to which of the following?

A. Shifting of the oxygen dissociation curve to the left
B. Shifting of the oxygen dissociation curve to the right
C. Causes an increased delivery of oxygen to tissues
D. Decreases the oxygen affinity of the remaining 3 oxygen-binding sites

A

A. Shifting of the oxygen dissociation curve to the left

86
Q
  1. Which can be omitted in managing patients with thalassemia and other hemoglobinopathies?

A.Iron supplements
B.Folic acid supplements
C.Blood transfusions
D.Chelation

A

A.Iron supplements

87
Q
  1. This accounts for the largest fraction of the total haemoglobin (90%);

A. HbA
B. HbF
C. HbA2
D. HbA1c

A

A. HbA

88
Q
  1. What happens to the oxygen dissociation curve of an anemic patient?

A. There is a “shift to the left” with associated reduction of the affinity of hemoglobin to oxygen
B. There is a “shift to the left” with associated increase of the affinity of hemoglobin to oxygen
C. There is a “shift to the right” with associated reduction of the affinity hemoglobin to oxygen
D. There is a “shift to the right” with associated increase of the affinity hemoglobin to oxygen

A

C. There is a “shift to the right” with associated reduction of the affinity hemoglobin to oxygen

89
Q
  1. Which of the following red cell indices show the differences in the sizes of RBCs and is being postulated to be a predictor of risk for mortality in carbon monoxide poisoning?

A. Mean corpuscular volume
B. Red cell distribution width
C. Mean corpuscular hemoglobin
D. Mean corpuscular hemoglobin concentration

A

A. Mean corpuscular volume

90
Q
  1. An individuals ABO blood type is normally detrmined by;

A. Genetic inheritance and environmental influences during life
B. Environmental influences alone
C.The inheritance of 1 of 3 possible alleles from each parent
D. AOTA

A

D. AOTA

91
Q
  1. If one of your parents is blood type A and the other is type B, which of the following blood types would you likely be?

A. AB
B. B
C. O
D. A

A

A. AB

92
Q
  1. Could a man with type O blood and a woman with type AB blood produce child with type O blood?

A. Not possible
B. Possible

A

A. Not possible

93
Q
  1. A mother of known blood type A has a child whose blood turns out to be B. From this it follows that the mother;

A. Is heterozygous for the trait
B. Must really have the blood type AB
C. Is homozygous dominant for the trait
D. Could have several possible genotypes

A

A. Is heterozygous for the trait

94
Q
  1. The biochemical basis of ABO blood group system is

A. A set of two different terminal carbohydrate antigen structures
B. A set of three different terminal carbohydrate antigen structures
C. A set of two different protein antigen structures
D. A set of three different protein antigen structures”

A

B. A set of three different terminal carbohydrate antigen structures

95
Q
  1. Hemolytic disruption of the erythrocyte
    involves;

a. An alteration in the erythrocyte membrane
b. A defect of the hemoglobin molecule
c. An antibody coating the erythrocyte
d. Physical trauma

A

a. An alteration in the erythrocyte membrane

96
Q
  1. The feature not seen in haemolytic anemia is;

a. Increase urobilinogen in urine
b. Increased serum bilirubin
c. Decreased iron stores
d. Increased stercobilinogen in stool

A

d. Increased stercobilinogen in stool

97
Q
  1. The following features are characteristic of intravascular red cell destruction except;

A. Increased haptoglobin
B. Hemosidenuria
C. Hemoglobinuria
D. Hemoglobinemia

A

D. Hemoglobinemia

98
Q
  1. The feature indicative of extravascular red cell destruction is;

A. Hemoglobinemia
B. Decreased haptoglobin
C. Splenomegaly
D. Hemoglobinuria

A

C. Splenomegaly

99
Q
  1. The following is not a feature of hemolytic anemias;
    A. Accumulation of products of hemoglobin
    B. A shortened red cell life span
    C. Elevated erythropoietin levels
    D. Defective DNA synthesis
A

C. Elevated erythropoietin levels

100
Q

Phenylketonuria (PKU)

A

(-) major enzyme (Phe Hydroxylase)
(-) DHB, NADPH or both
(-) DHB reductase

101
Q

Alkaptonuria

A

(-) Homogentisate Dioxygenase

Ochronosis (connective tissue pigmentation)
Arthristis
Black urine (homogenistic acid in the urine)

102
Q

Tyrosinemia Type T
(Hepatorenal Tyrosinemia)

A

(-) Fumaylacetoacetate hydrolase
liver failure
kidney failure
Tumorigenesis

103
Q

Tyrosinemia Type lI
(Oculocutaneous Tyrosinemia/ Richner-Hanhart Syndrome)

A

(-) Tyrosine aminotransferase
eye and skin lesions

104
Q

Glycolysis

A

Phosphofructokinase

105
Q

Gluconeogenesis

A

Fructose 1,6-Biphosphatase

106
Q

Glycogenesis

A

Glycogen synthase (Dephosphorylase)

107
Q

Glycogenolysis

A

Glycogen phosphorylase

108
Q

Pentose Phosphate Pathway

A

Glucose-6-Phosphate dehydrogenase

109
Q

Maple Syrup Disease

A

Branched chain alpha keto acid dehydrogenase

110
Q

Albinism

A

Tyrosinase (decrease melanin)

111
Q

Von Gierke

A

Glucose-6- Phosphatase (Von GP)

112
Q

Pompe

A

Lysosomal α (1,4) glucosidase (PomLy)

113
Q

Andersen

A

Branching enzyme

114
Q

Cori

A

Debranching enzyme

115
Q

McArdle

A

Muscle glycogen phosphorylase

116
Q

Hers

A

Hepatic glycogen phosphorylase

117
Q

Tarui

A

Phosphofructokinase-1 (TruFu)

118
Q

Glysine

A

Serine

119
Q

Glutamic Acid

A

Proline
Alpha-Ketoglutarate
Glutamine
Ariginine
Histine

120
Q

Alanine

A

Pyruvate

121
Q

Aspartic acid

A

Oxaloacetate

122
Q

Tryptophan

A

Alanine

123
Q

Phenylalanine

A

Tyrosine

Biochemisty Main (29 decks)

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