Biochemistry MCQs

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

1,2,3

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?

glucose transporter type 2 (GLUT2)

glucose transporter type 5 (GLUT5)

Na-dependent glucose transporter (SGLT1)

glucose transporter type 1 (GLUT1)

Na-dependent glucose transporter (SGLT1)

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

1,2,3,4

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

pyridoxalphosphate

thiamine pyrophosphate

coenzyme-A

lipoic acid

pyridoxalphosphate

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

Phosphofructokinase-2 (PFK-2)

Aldolase

Phosphoglycerate kinase

Phosphofructokinase-1 (PFK-1)

Phosphofructokinase-1 (PFK-1)

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

ATP

Glucose-6-phosphate

AMP

Fructose-2,6-bisphosphate

Glucose-6-phosphate

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

1,2,3,4

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

Glucose-6-phosphate

Glucose

Glucose-1-phosphate

None of the mentioned above

Glucose-1-phosphate

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

Glucose-6-phosphatase

Glucokinase

Phosphoglucomutase

Hexokinase

Hexokinase

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

Pyruvate kinase

Enolase

Lactate dehydrogenase

Glyceraldehyde-3-phosphate dehydrogenase

Lactate dehydrogenase

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

c

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

1,2,3

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

Phosphoglycerate kinase

Phosphofructokinase 1

Phosphofructokinase 2

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

Two

Eight

Thirty six

Four

Two

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:

Glucagon

Adrenaline

Insulin

None of the mentioned above

Insulin

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

Glycolysis

Gluconeogenesis

Pentose phosphate pathway

Oxidative decarboxylation of pyruvate

Pentose phosphate pathway

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

1,3

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

It is performed actively in skeletal muscle

Supplies NADPH for fatty acid, cholesterol biosynthesis etc..

The acyl-CoA derivatives inhibit the regulatory enzyme

In the first (oxidation) step of the process 2 molecules NADPH are obtained

It is performed actively in skeletal muscle

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:

Phosphofructokinase 1

Hexokinase

Pyruvate kinase

Phosphoglucomutase

Pyruvate kinase

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

Pyruvate kinase

Phosphofructokinase 1

Aldolase

Phosphoglucomutase

Pyruvate kinase

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?

Transketolase

Phosphogluconolaktonase

Glucose-6-phosphate dehydrogenase

Transaldolase

Glucose-6-phosphate dehydrogenase

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:

pyridoxal phosphate

thiamine pyrophosphate

NADP

FAD

thiamine pyrophosphate

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

2,4

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

Provides ribose-5-phosphate for the synthesis of nucleotides

Provides NADPH for fatty acid synthesis

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

Provides NADPH of cholesterol synthesis

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

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

d

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

1,2,3

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:

pyruvate carboxylase

glucose-6-phosphatase

fructose-1,6-bisphosphatase

phosphoenolpyruvate-carboxykinase (PEPKK)

fructose-1,6-bisphosphatase

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

pyruvate carboxylase

phosphoglycerate kinase

glucose-6-phosphatase

phosphoenolpyruvate-carboxykinase (PEPKK)

phosphoenolpyruvate-carboxykinase (PEPKK)

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

Cortisol

Insulin

Aldosterone

Adenocorticotropic hormone (ACTH)

Cortisol

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

Citrate

Oxaloacetate

α- -Ketoglutarate

Fumarate

Oxaloacetate

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

Fructokinase

Aldolase B

Ttriosokinase

none of the above mentioned

Aldolase B

Which of the following enzymes involved in the catabolism of galactose catalyze the metabolic step of the conversion of galactose to galactose-1-phosphate

Galactose-1-phosphate uridyltransferase

UDF- galactose-4-epimerase

Galactokinase

Phosphoglucomutase

Galactokinase

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

Glucose-6-phosphatase

Fructose-1,6-bisphosphatase

Phosphoenolpyruvate-carboxykinase (PEPKK)

Pyruvate carboxylase

Pyruvate carboxylase

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

Glucose-6-phosphate

Glucose-1-phosphate

UDP-glucose

None of the above mentioned

UDP-glucose

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

АTP

АМP

glucose-6-phosphate

fructose-2,6-bisphosphate

glucose-6-phosphate

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:

Pyruvate

Dihydroxyacetone phosphate

Phosphonenolpyruvate

Fructose-6-phosphate

Dihydroxyacetone phosphate

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

During its degradation lactate is released in the blood

Glucagon stimulates its synthesis

It is broken down during the periods of fasting

adrenaline stimulates its synthesis

It is broken down during the periods of fasting

In which of the following organs the gluconeogenesis is performed:

1) liver

2) small intestine

3) renal cortex

4) skeletal muscles

1,3

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

fructose-6-phosphate → Glucose-6-phosphate

pyruvate →oxaloacetate

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

oxaloacetate → phosphonenolpyruvate

fructose-6-phosphate → Glucose-6-phosphate

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)

c

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

glycogen synthase

glycogen phosphorylase

phosphoglucomutase

amylo-1,4 → 1,6-transglycosylase

glycogen phosphorylase

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

it is synthesized after carbohydrate-rich food intake

insulin stimulates its synthesis

it is broken down in conditions with high blood glucose levels

by degradation it provides blood glucose

it is broken down in conditions with high blood glucose levels

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

c

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:

kinase of phosphorylase

phosphoglucomutase

glucose-6-phosphatase

glycogen phosphorylase

glucose-6-phosphatase

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:

Adrenaline

Adenylyl cyclase

Protein kinase A

Glucagon

Glucagon

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

b

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)

d

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

calcium ions

cAMP

diacylglycerol

inositol-triphosphate

cAMP

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

glucosuria

ketoacidosis

hypoglycemia

polyuria

hypoglycemia

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

glucagon

insulin

adrenaline

cortisol

insulin

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

c) glutamine

d) glutamate

b

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

1,3

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

d

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

2,4

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

b

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

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

7. Coproporphyrinogen Type I

А) is an intermediate metabolite in the synthesis of heme

B) is an intermediate metabolite in the degradation of heme

а) А

b) B

c) А and B

d) neither А nor B

d

8. 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

a

9. In enzyme defect (deficiency) 5-Ala dehydratase (porphobilinogen synthase) the following clinical signs are observed:

А) severe abdominal pains thrusts

Б) skin photosensitivity

a) А

b) B

c) A and B

d) neither А nor B

a

10. 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

4

11. 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

1+3

12. 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)

4

13. 5 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

1,2,3

14. 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

c) the conversion of ribonucleotides into deoxyribonucleotides

15. 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

2,4

16. 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

2,4

17. 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

b) the conversion of ATP into CTP

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

1) thyroxine

2) melanin

3) dopamine

4) melatonin

4

19. End products of the N-metabolism, which are excreted from the body are:

1) urea

2) creatine

3) uric acid

4) acetoacetate

1,3

20. Metabolites of Ornithine cycle are:

1) succinyl CoA

2) citrulline

3) 5- Aminolevulinic acid

4) carbamoyl phosphate

2,4

21. Pyrimidines degradation products are:

1) β-aminoisobutyrate

2) urea

3) β-alanine

4) orotic acid

1,3

22. Regulatory enzymes of purines de novo synthesis are:

1) xanthine oxidase

2) PRPP amidotransferase

3) adenine phosphoribosyltransferase

4) adenilosuccinate synthetase

2,4

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

b

24. Tetrahydrobiopterin is required to:

a) methylation of dUMP

b) degradation of Tyr

c) hydroxylation of phenylalanine

d) transfer of one-carbon groups (fragments)

c

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

a

26. 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)

d

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

1) glycine

2) methionine

3) arginine

4) glutamine

1,2,3

28. Transamination reactions require one of the following vitamins

a) riboflavin

b) pantothenate;

c) thiamine;

d) pyridoxol (b6);

d

29. 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

1,3

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

b

31. 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

1,2,4

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

а) thiamine

b) pyridoxine

c) niacin

d) riboflavin

b

33. 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

b

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

1,2,3

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

b

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

c

37. To which of the following metabolites some of glycogen amino acids are degraded?

1. pyruvate

2. acetoacetate

3. oxaloacetate

4. fumarate

1,3,4

38. Which of these amino acids is only ketogenic amino acid?

а) tryptophan

b) leucine

c) isoleucine

d) alanine

b

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

a) homogentisate oxidase

b) tyrosine transaminase

c) dihydrobiopterin reductase

d) phenylalanine hydroxylase

d

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

1. thyroxine

2. melatonin

3. melanin

4. serotonin

2,4

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

1. thyroxine

2. melatonin

3. melanin

4. dopamine

1,3,4

42. 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)

b

43. 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

2,4

44. 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

c

45. 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

b

46. 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

2,4

47. 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

a

48. 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

c

49. 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

b

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

d