Download Examination test of Proteins The repeating units of proteins are

Examination test of Proteins
1. The repeating units of proteins are
a) Glucose units
b) *Amino acids
c) Fatty acids
d) Peptides
2. Amino acids are joined by
a) *Peptide bond
b) Hydrogen bond
c) Ionic bond
d) Glycosidic bond
3. The primary structure of protein represents
a) *Linear sequence if amino acids joined by peptide bond
b) 3-dimensional structure of protein
c) Helical structure of protein
d) Sub unit structure of protein
4. Peptide bonds is
a) Rigid with partial double bond
b) Planar, covalent
c) Covalent
d) *All of the above
1
5. Hemoglobin has
a)
b)
c)
d)
Primary structure
Secondary structure
Tertiary structure
*Quaternary structure
6. The 3-D structure of protein can be determined by
a) Nuclear magnetic resonance
b) X-ray crystallography
c) *Both a and b
d) Spectroscopy
7. Myoglobin is a
a) Protein with primary structure
b) Protein with secondary structure
c) *Protein with tertiary structure
d) Protein with quaternary structure
8. The key enzyme in the regulation of fatty acid synthesis is
a) *acetyl CoA carboxylase
b) AMP activated proteinkinase
c) protein phosphatase
d) none of these
2
9. Arachidonate has 20 carbon atoms with
a) 3 double bonds
b) 2 double bonds
c) *4 double bonds
d) 8 double bonds
10. In the intestine, the dietary fats are hydrolysed by
a) triacylglycerol lipase
b) adenylate cyclase
c) *pancreatic lipase
d) protein kinase
Examination test of Aminoacids
1. Histidine is degraded to α-ketoglutarate and is described as a
a) gluco amino acid
b) *glucogenic amino acid
c) ketogenic amino acid
d) keto-gluco amino acid
2. Which of the following amino acids is considered as both ketogenic and glucogenic?
a) Valine
c) None of these
b) *Tryptophan
d) Lysine
3. A glucogenic amino acid is one which is degraded to
a) keto-sugars
b) either acetyl CoA or acetoacetyl CoA
c) *pyruvate or citric acid cycle intermediates
d) none of the above
4. Which of the following is the best described glucogenic amino acid?
a) Lysine
b) Tryptophan
c) *Valine
d) phenylalanine
5. Amino acids from N-end in the proteins are splittted off by
A. Dipeptidase
B. Carbooxypeptidase
C. * Aminopeptidase
D. Elastase
6. Oxidative deamination is the conversion of an amino
a) group from an amino acid to a keto acid
b) acid to a carboxylic acid plus ammonia
c) *acid to a keto acid plus ammonia
d) group from an amino acid to a carboxylic acid
7. An example of a transamination process is
a) glutamate = hexanoic acid + NH3
b) aspartate + hexanoic acid = glutamate + oxaloacetate
c) *aspartate + α ketoglutarate = glutamate + oxaloacetate
d) glutamate = α-ketoglutarate + NH3
3
8. Which one of the following is an essential amino acid?
a) Arginine
b) Tyrosine
c) * Phenylalanine
d) Proline
9. One of the following amino acid is solely ketogenic:
a) * Lysine
b) Alanine
c) Valine
d) Glutamate
10. For effective formation of urea in the liver with great intensivity must proceed ornithinic
cycle. In the other case the concentration of ammonia in blood grows rapidly. By the lack of
what amino acid in the food can evolve azotemia?
a) * Arginine
b) Alanine
c) Lysine
d) Serine
11.
Tyrosine is degraded to acetoacetyl CoA and fumarate and is described as a
a) glucogenic amino acid
b) ketogenic amino acid
c) *ketogenic and glucogenic amino acid
d) keto-gluco amino acid
12.
In the normal breakdown of phenylalanine, it is initially degraded to
a) Fumarate
c) phenylpuruvate
b) lysine
*d) tyrosine
13. Amino acids that contribute to the basic properties of the protein part of nucleoproteins
a) glutamic acid and aspartic
b) * Arg, Lys
c) Ser, threonine
g) Cystine, Cysteine
14. Non essential amino acids;
a) Phenylalanine
b) *Tyrosine
c) Tryptophan
g) Threonine
15. Amino acids - propionic acid derivatives
a) *alanine
b) serine
c) Cysteine
g) threonine
16. The strongest bonds in the molecule of the protein:
a) *peptide
b) disulfide
c) Hydrogen
4
g) Ionic
17. For protein purification of salts using methods
a) *gel filtration, dialysis,
b) all of the above
b) paper chromatography
g) hydrolysis
18. What are acidic amino acids
a).  - aminobutyric acid and asparagine е ) and glutamic pyruvic
b). Aspartic,  - aminobutyric acid
d). * Aspartic and glutamic
19. What are amino acids involved for disulfide bond formation?
a). Serine, methionin
e). Cysteine, serine
b). *Cysteine, cysteine
g). Cysteine, histidine
20. Name the sulfur amino acids
a). Asparagine, glutamin
b). Cysteine, serine
c). * cysteine, methionine
d). Cystine, serine
21. Exopeptidases are:
a)Pepsin, trypsin
b)Elastase, colagenase
c)* Carboxypeptidases, aminopeptidases
d)Chymotrypsin, carboxypeptidases
22. Tyrosine produced from:
a) *catecholamines;
b) the melatonin;
c) lipoic acid;
g) hydroxytryptamine.
23. How can you destroy the peptide chain:
a) by acid hydrolysis or oxidation
b) * by alkaline hydrolysis, or by heating
c) by enzymatic hydrolysis or hydrogenation
d) by acid, alkali or enzymatic hydrolysis
24. Call cyclic amino acids:
a) phenylalanine, tyrosine, histidine, lysine, proline
b) phenylalanine, valine, tryptophan, proline.
c) *phenylalanine, tyrosine, histidine, tryptophan, proline
g) lysine, phenylalanine, histidine.
25. What is called peptides:
a) high-molecular compound consisting of α-amino acids
b) *low molecular weight compounds consisting of amino acid residues of α-linked
together by peptide bonds
5
c) low molecular weight compounds consisting of amino acid residues of β-linked
together by peptide bonds
d) substance having a peptide bond
26. Lack of amino acids which promotes fatty liver
a) tryptophan;
b) arginine;
c) * methionine;
d) valine;
27. What protein fraction in plasma antibodies serve as:
a) α-1 - globulins;
b) *γ-globulin;
a) α-2 - globulins
g) β-globulins
28. Proteins are characterized by:
a) inability to crystallize
b) lack of specific molecular configuration
c) the preservation of the structure of molecules by heating
d) *amphoteric properties
Examination test of Nucleic acid
1. A nucleoside is composed of
a) *a base + a sugar
b) a base + a sugar + phospnate
c) a base + phospnate
d) phospnate + base
2. Genetic mutation occurs in
a) Protein
b) RNA
c) *DNA
d) Nucleus
3. DNA is present in
a) Nucleus only
b) Nucleus, mitochondria and ER
c) Nucleus , mitochondria and chloroplast
d) *Nucleus, mitochondria and RER
4. DNA is genetic material in
a) Viruses, prokaryote and eukaryote
b) Prokaryote and eukaryote
c) Only eukaryotes
6
d) *In some, prokaryotes and eukaryote
5. The two strands in a DNA double is joined by
a) Covalent bond
b) Nitrogen bond
c) Ionic bond
d) *Phosphodiester bond
6. Chromatin is composed of
a) *Nucleic acids and protein
b) Nucleic acids only
c) Proteins only
d) Peptides only
7. The basis repeating units of DNA molecule is
a) Nucleoside
b) *Nucleotide
c) Histones
d) Aminoacid
8. The the of sugar in DNA are
a)
b)
c)
d)
Triose
Tetrose
*Pentose
Hexose
9. A short length of DNA molecule has 80 thymine and 80 guanine bases. The total number
of nucleotide in the DNA fragment is
a) 160
b) 40
c) *320
d) 640
10. The length of DNA having 23 base pairs is
a) 78,4 A0
b) 78,2 A0
c) *78,8 A0
d) 78 A0
7
Examination test for Vitamins
1.
The composition pyridine dependents dehydrogenases include:
a) vitamin B2;
c) *vitamin PP;
b) vitamin B1;
d) pantothenic acid and cytochromes;
2. The composition of flavin dependents dehydrogenase include:
a) inositol;
c) coenzyme A (CoA).
b) ubiquinone;
d) * vitamin B2;
3. The structure of rhodopsin - retinal receptor protein includes:
a) riboflavin;
c) * retinal;
b) calciferol;
g) tocopherol;
4. The structure of the FAD-dependent oxidoreductases include vitamin:
a) B3
c) B5
b) *B2
g) A
5. The structure of NAD-dependent oxidoreductases include vitamin:
a) B1
b) *PP
c) H
g) B2
6. Chemical composition of vitamin B12 is given by:
a) S90N36N14PCO
c) C90H63N14PCO
b) *C36H90NPCO
d) C63H90N14PCo
7. Vitamin B1 prevents the development of:
a) dermatitis
c) *night blindness
b) polyneuritis
d) scurvy
8. What vitamins are deposited in the animal organism:
a) A, B2, C, D
c) D, E, K, A
b) *B1, H, P, E
d) A, E, D, H
9. Coenzyme form of vitamin B1
a) NAD
c) FAD
b) *TPP
d) PP
10. When vitamin D vitamin deficiency disease occurs:
a) "beriberi"
c) anemia
b) *rickets
g) scurvy
8
11. Fat-soluble vitamins:
a) soluble in water and fats,
b) form coenzyme forms,
c) *accumulates in the tissues
g) called accumulates
12. Most vitamin C is contained in:
a) needles
b) apple
c) * the wild rose
g) blackcurrants
13. Vitamin B1 coenzyme forms:
a) CoA
b) FAD
c) NAD
d) * TPP
14. Cobalt atom is part of the vitamin:
a) A
b) *B12
c) B6;
d) R
15. S.Funk established structure of vitamin:
a) PP
b) pyridoxine
c) retinol
d) * thiamine
16. The sulfur atom is included in the composition of vitamins:
a) *B6 and B1
b) B1 and H
2) H and B3
r) S and K
17. Precursor of vitamin D2 is:
a) carotene
c) *7-lenydrocholesterol
b) ergo sterol
d) choline
18. Vitamin B2 is involved in this exchange:
a) nucleic acid
c) sulfur
b) *carbohydrate
d) Water
19. Tocopherol vitamin warns:
a) rickets
c) anemia
b) dementia
d) * infertility
20. Nitrogen atom is part of the vitamin:
a) A
c) R
b) C
d) * B6
9
21. Major sources of cobalamin:
a) *Liver
c) Root crops
b) the waste water
d) vegetables
22. Vitamins are classified into:
a) *fat-soluble, water-soluble
b) antivitamins
c) water-soluble, non fat-vitamins
d) hormone
23. Indicate any vitamin formula shown below?
a)
b)
c)
d)
vitamin C
*vitamin E
Vitamin PP
Vitamin B12
24. Indicate any vitamin formula shown below?
a)
b)
c)
d)
vitamin C
vitamin E
Vitamin PP
*Vitamin B6
25. Which substance is a member of folic acid?
a) ascorbic acid
b) *Paraaminobenzoic acid
c) pantothenic acid
d) Isoalloxazine
26. Vitamin B6 is involved in the reactions:
a) methylation
c) *transamination
b) Phosphorylation
g) carboxylation
27. Vitamin D regulates the body content:
a) sodium
c) Potassium
b) * Calcium
d) Magnesium
28. When thiamine vitamin deficiency disease develops:
a) rickets
c) *"beri-beri"
b) anemia
d) Dermatitis
29. Vitamins are a part:
a) *coenzymes
b) Enzymes
c) hormones
g) antivitamin
10
30. Absorption of vitamin D in intestine is helped by:
a) *Calcium
c) Potassium
b) Magnesin
g) Iron
31. A deficiency of vitamin B12 causes
A.
B.
C.
D.
Beri-Beri
Scurvy
* Perniciuos anemia
Ricket
32. A provitamin D synthesized in human beings is
a) Ergosterol
b) * 7-Dehydrocholesterol
c)Cholecalciferol
d)25-Hydroxycholecalciferol
33. A vitamin which can be synthesized by human beings is:
a)Thiamin
b)* Niacin
c)Folic acid
d)Cyanocobalamin
34. Anti-egg white injury factor is:
a)Pyridoxine
b)* Biotin
c)Thiamin
d)Liponic acid
35. Biotin is a coenzyme of the enzyme:
a. * Carboxylase
b. Hydroxylase
c. Decarboxylase
d. Deaminase
36. Daily requirement of vitamin C in adults is about:
a. 100 mg
b. 25 mg
c. * 70 mg
d. 100 mg
37. Deficiency of Vitamin A causes
11
a.
b.
c.
d.
* Xeropthalmia
Hypoprothrombinemia
Megaloblastic anemia
Pernicious anemia
38. Deficiency of vitamin D causes
a. * Rickets and osteomalacia
b. Tuberculosis of bone
c. Hypothyroidism
d. Skin cancer
39. Fat soluble vitamins are
a. Soluble in alcohol
b. one or more Propene units
c. Stored in liver
d. * Cause hypervitaminosis
40. Niacin can be synthesised in human beings from
a. Histidine
b. Phenylalanine
c. Tyrosine
d. * Tryptophan
41. Provitamin D3 is
a. Cholecalciferol
b. Ergosterol
c. * 7-Dehydrocholesterol
d. Ergocaliferol
42. Retinol and retinal are interconverted requiring dehydrogenase or reductase in the
presence of
a. * NAD or NADP
b. NADH + H+
c. NADPH
d. FAD
43. Riboflavin deficiency symptoms are:
a. Glossitis
b. Stomatis
c. Vomitting
d. * Glossitis and Stomatis
44. Sulphydryl group of coenzyme a is contributed by:
a. Alanine
b. α-Aminoisobutyric acid
c. Methionine
d. * Thioethanolamine
45. The most important natural antioxidant is
a. Vitamin D
b. * Vitamin E
c. Vitamin B12
d. Vitamin K
46. The pellagra preventive factor is:
a. Riboflavin
12
b. Pantothenic acid
c. * Niacin
d. Pyridoxine
47. The requirement of vitamin E is increased with greater intake of
a. Carbohydrates
b. Proteins
c. * Polyunsaturated fat
d. Saturated fat
48. Tocopherols prevent the oxidation of
a. * Vitamin A
b. Vitamin D
c. Vitamin K
d. Vitamin C
49. Vitamin B12 is:
a. Not stored in the body
b. Stored in bone marrow
c. * Stored in liver
d. Stored in RE cells
50. Vitamin E reduces the requirement of
a. Iron
b. Zinc
c. * Selenium
d. Magnesium
51. 1,25-dihydroxycholecalciferol promotes absorption of:
a. * Ca
b. Cu
c. Zn
d. Na
52. A poor source of Vitamin D is
a. Egg
b. Butter
c. * Milk
d. Liver
53. Active coenzyme forms of vitamin B5:
a. FAD and FMN
b. Pyridoxal phosphate
c. * Pantothenic acid
d. Pyridoxamine
54. Anaemia can occur due to the deficiency of all the following except:
a. * Thiamin
b. Pyridoxine
c. Folic acid
d. Cyanocobalamin
55. Analog of vitamin K:
a. * Dicumarol
b. Prothrombin
c. Fibrinogen
d. Proconvertin
56. Calcitriol synthesis involves
13
a. * Both liver and kidney
b. Intestine
c. Adipose tissue
d. Muscle
57. Folate deficiency causes
a. Microcytic anemia
b. Hemolytic anemia
c. Iron deficiency anemia
d. * Megaloblastic anemia
58. Insufficiency of which vitamin does cause the inhibition of activity of aminotransferase’s
and decarboxylase?
a. B3
b. B2
c. * B6
d. B12
59. Name the active coenzyme form of vitamin B2:
a. A.TMP, TDP
b. NAD, NADP
c. * FMN, FAD
d. Coenzyme A
60. Pyridoxal phosphate is central to:
a. Deamination
b. Amidation
c. Carboxylation
d. * Transamination
61. Pyridoxal phosphate is the active coenzyme form of vitamin:
a. B1.
b. B2.
c. B3.
d. *B6
62. The active form of vitamin D (1,25-dihydrocholecalciferol) maintain in an organism a
constant level of:
a. Potassium and phosphorus
b. * Calcium and phosphorus
c. S. Iron and calcium
d. Iron and magnesium
CARBOHYDRATE
1. Fructose is metabolized by
a)
b)
c)
d)
Fructose 1-phosphate pathway
fructose 6-phosphate pathway
glyceraldehyde 3-phosphate pathway
*both (a) and (b)
14
2. A common way that cells capture the energy released during the breakdown of large
molecules is to add electrons to smaller, specialized molecules that can accept them.
This process of electron acceptance is otherwise known as
a) biosynthesis
b) metabolism
c) *reduction
d) catalysis
3. Humans are unable to digest
a) Starch
b) complex carbohydrates
c) denatured proteins
d) *cellulose
4. How many ATP equivalents per mole of glucose input are required for
gluconeogenesis?
a) 2
b) *6
c) 8
d) 4
5. Which of the following compounds is responsible for coordinated regulation of glucose
and glycogen metabolism?
a) NAD
b) *Fructose 2,6 bisphosphate
c) Acetyl-CoA
d) Fructose 1,6 bisphosphate
6. Name the glycolysis reactions, flowing with the formation of ATP:
a) hexokinase, enolase
b) enolase, aldolase
c) * phosphoglycerate kinase, pyruvate kinase
d) pyruvate kinase, lactate dehydrogenase
7. Which of the following is carried out when cAMP functions as a second messenger?
a) Acts second in importance to AMP
b) Activates all cytosolic protein kinases
c) *Activates the cAMP-dependent protein kinase
d) all of the above
8. The production or break down of __________ is often coupled with the metabolic
reactions of biosynthesis and catabolism.
a) aspirin
b) DNA
c) *ATP
d) CO2
9. The cells dependent solely on glucose as an energy source are
a) muscle cells
b) *brain cells
15
c) kidney cells
d) liver cells
10. The main site for gluconeogenesis is
a) kidney
b) *liver
c) brain
d) muscle
11. Which of the following statements about the energy needs of cells is false?
a) Without a continuous input of energy, cell disorder will increase
b) The laws of thermodynamics force cells to acquire energy
c) Many cellular reactions have an associated activation energy
d) * The most usable energy for cells comes from the rapid combustion of glucose
12. In lysozyme catalysis, which of the following does not contribute?
a) The abnormally high pKa of Glu35
b) The strained conformation of the D sugar
c) Formation of a covalent intermediate at Asp52
d) *Formation of a covalent intermediate at Ser195
13. Cellulose fibers resemble with the protein structure in the form of
a) β-sheets
b) *α-helices
c) β-turns
d) None of these
14. During vigorous exercise, pyruvate produced by glycolysis is converted to
a) acetate
b) *lactate
c) monosodium phosphate
d) pyruvic acid
15. Glucagon and epinephrine
a) inhibits gluconeogenesis and stimulates glycolysis
b) stimulates gluconeogenesis and glycolysis
c) *stimulates gluconeogenesis and glygenolysis
d) inhibits gluconeogenesis and glycolysis
16. The NAG6 substrate is hydrolyzed by human lysozyme to form
a) 6 glucosamines + 6 acetic acids
b) *NAG4 + NAG2
c) NAG3 + NAG3
d) NAG3
17. Gluconeogenesis uses
a) 3 ATPs and 2 GTPs per glucose
b) 2 ATPs and 1 GTPs per glucose
c) 3 ATPs and 3 GTPs per glucose
d) *4 ATPs and 2 GTPs per glucose
18. The concentration of blood lactate is normal:
16
a) 4,4-6,6 mmol/l
b) 3,3-5,5 mmol/l
c) 4,4-5,5 mmol/l
d) * 1-2 mmol/l
19. The conversion of pyruvate to oxaloacetate
a)* requires biotin
b) involves the fixation of carbon dioxide
c) occurs in the mitochondria
d) all of the above
20. Gluconeogenesis is the
a) formation of glycogen
b) breakdown of glucose to pyruvate
c) breakdown of glycogen to glucose
d) *synthesis of glucose from non-carbohydrate precursors
21. Hydrolysis of lactose yields
a) galactose and fructose
b) *galactose and glucose
c) glucose and fructose
d) fructose and galactose
22. Two major products of pentose phosphate pathway are
a) *nicotinamide adenine dinucleotide and ribose 5-phosphate
b) flavine adenine dinuclueotide and glucose 5-phosphate
c) FAD and CoA
d) NADPH and NAD
23. The preparatory stage of glycolysis ends with the formation of:
a) *fructose-1,6-diphosphate
b) glucose-6-phosphate
c) two trioses (dihydroxyacetone phosphate and glyceraldehydetryphosphate)
d) 2-phosphoglycerate
24. Pyruvate is initially converted to which of the following in the gluconeogenesis?
a) Glycerol
b) Phosphoenol pyruvate
c) *Oxaloacetate
d) Acetyl CoA
25. Boat and chair conformations are found
a) *in pyranose sugars
b) in any sugar without axial -OH groups
c) in any sugar without equatorial -OH groups
d) only in D-glucopyranose
26. The conversion of pyruvate to lactate is catalysed by
a) pyruvate carboxylase
b) *lactate dehydrogenase
c) pyruvate dismutase
d) pyruvate decarboxylase
27. Which glycolysis enzyme requires insulin as activator?
a) Hexokinase
b) glucose-6-phosphatase, phosphoglucomutase
c) glucose-6-phosphate-isomerase, aldolase
17
d) *aldolase, lactate dehydrogenase
28. α-amylose is similar to
a) β-sheets
c) *α-helices
b) β-turned coils
d) the hydrophobic core
29. Storage polysaccharide made by animals is
a) amylopectin
b) *glycogen
c) cellulose
d) collagen
30. A basic role in digestion of carbohydrates in a digestive tract belongs following
enzymes:
a) Alfa-amylase, hexokinase, lactase
b) Maltase, sucrase, enterokinase
c) * Lactase, alfa-amylase, sucrase
d) Sucrase, maltase, glycogen phosphorylase
31. The sugar which forms major component of nucleic acids is
a) *ribose
b) galactose
c) mannose
d) maltose
32. Under aerobic condition pyruvate is converted by pyruvate dehydrogenase to
a) phosphoenol pyruvate
b) acetyl CoA
c) * lactate
d) glyceraldehyde 3 phosphate
33. Aerobic glycolysis is a multi-stage process of transformation of molecule of glucose to
pyruvate. Choose this process:
a) С6Н12О6 С3Н4О3
b) *С6Н12О6 С5Н10О4
c) С6Н12О66 С2Н5ОН + 2 СО2
d) С6Н12О62С3Н4О3
34. The ultimate source of energy that sustains living systems is
a) glucose
b) oxygen
c) *sunlight
d) carbon dioxide
35. Citric acid accumulation would
a) stimulate phosphofructokinase activity
b) stimulate phosphofructokinase activity
c) inhibit phosphofructokinase activity
d) * both (b) and (c)
36. Which of the following is not involved in the biosynthesis of DNA?
a) Energy from ATP
b) Mononucleotides
c) *Carbonic anhydrase
d) Enzymes
37. Insulin
a) stimulates gluconeogenesis and glycolysis
b) stimulates gluconeogenesis and inhibits glycolysis
18
c) inhibits gluconeogenesis and glycolysis
d) *inhibits gluconeogenesis and stimulates glycolys
38. What is present in the stomach to prevent self-digestion?
a) *Mucus
b) acid
c) Enzymes
d) hormones
Glycolysis
1. Choose the reaction of glycolysis, which catalyzed with phosphoglucoisomerase:
A. Glucose -6-phosphate - glucose -1-phosphate
B. Glucose -6-phosphate - glucose
C. Glucose G glucose -6-phosphate
D. * Glucose -6-phosphate - fructose -6-phosphate
2. During catabolism, only about 40% of the energy available from oxidizing glucose is used
to synthesize ATP. Remaining 60%
a) *is lost as heat
b) is used to reduce NADP
c) remains in the products of metabolism
d) is stored as fat.
3. Why does the glycolytic pathway continue in the direction of glucose catabolism?
a) *There are essentially three irreversible reactions that act as the driving force for the pathway
b) High levels of ATP keep the pathway going in a forward direction
c) The enzymes of glycolysis only function in one direction
d) Glycolysis occurs in either direction
4. The released energy obtained by oxidation of glucose is stored as
a) a concentration gradient across a membrane
b) ADP
c) *ATP
d) NAD+
5. A kinase is an enzyme that
a) removes phosphate groups of substrates
b) *uses ATP to add a phosphate group to the substrate
c) uses NADH to change the oxidation state of the substrate
d) removes water from a double bond
6. For every one molecule of sugar glucose which is oxidized __________ molecule of
pyruvic acid are produced.
a) 1
c) 3
b) *2
d) 4
7. In the glycogen synthase reaction, the precursor to glycogen is
a) glucose-6-P
b) UTP-glucose
c) *UDP-glucose
d) glucose-1-P
19
8.
The active form of glycogen phosphorylase is phosphorylated, while the
dephosphorylation of which active form occurs?
a) *Glycogen syntheses
b) Glycogen semisynthase
c) Glycogen hydrolase
d) Glycogen dehydrogenase
9. The amount of energy received from one ATP is
a) 76 kcal
b) * 7.3 kcal
c) 760 kcal
d) 1000 kcal
10. The enzymes of glycolysis in a eukaryotic cell are located in the
a) intermembrane space;
b) plasma membrane;
c) *cytosol,
d) mitochondrial matrix;
11. Cofactors of dehydrogenases are all, except one:
a)NAD+ ;
b)* c-AMP,
c)NADP+ ;
d)FMN ;
12. Aerobic oxidation of pyruvate to CO2 and H2O results in formation of molecules ATP:
a) 38 ATP
b) 12 ATP
c) *ATP
d) 15 ATP
13. In glycolysis, ATP is formed by the transfer of a high-energy phosphate from 1,3-
bisphosphoglycerate to ADR No such high-energy phosphate donor has ever been isolated
in mitochondria because
a) the techniques for isolating the phosphate donor are not refined enough
b) *no such phosphate donor exists
c) the high-energy phosphate donor is very short-lived and difficult to isolate
d) None of the above
14. ATP is from which general category of molecules?
a) Polysaccharides
b) Proteins
c) *Nucleotides
d) Amino acids
15. The glycolytic pathway (glucose → 2 pyruvate) is found
a) * in all living organisms
b) primarily in animals excluding particles
c) only in eukaryotes
d) only in yeast
16. Converting of glucose into lactic acid consists of eleven reactions. Almost of all reactions as
activators need ions:
e)
f)
g)
h)
Zn2+ ;
Ca2+ ;
Cl- ;
* Mg2+,
17. During glycolysis, isomerization occurs during which of the following reactions:
20
a) Fructose 1,6 bisphosphate -> dihydroxyacetone phosphate and glyceraldehyde 3-phosphate;
b) Fructose 6 phosphate -> fructose 1,6 bisphosphate;
c) * Glucose 6- phosphate -> fructose 6- phosphate,
d) Glucose -> glucose 6- phosphate;
18. Phosphofructokinase, the major flux-controlling enzyme of glycolysis is allosterically
inhibited and activated respectively by
a) ATP and PEP
c) *ATP and ADP
b) AMP and Pi
d) Citrate and ATP
19. Enzyme that catalyzes the reaction of fructose-1,6-diphosphate disintegration into two
trioses in the process of glycolysis is named:
a) glucokinase
b) glucose-6-phosphatase
c) phosphofructikinase
d) * aldolase
20. During glycolysis, the major energy generating step involves
a) pyruvate kinase
b) phosphoglycerate kinase
c) *glyceraldehyde-3 -dehydrogenase
d) Phosphofructokinase
21. Fructose-2,6-bisphosphate
a) pyruvate kinase
b) activates phosphofructokinase
c) inhibits fructose-1,6-bisphosphatase
d) *activates phosphofructokinase and inhibits fructose-1,6-bisphosphatase (c)
22. Glucose from the breakdown of glycogen is obtained in
a) the liver by phosphorolysis
b) the muscles by phosphorolysis
c) the muscles by hydrolysis
d) *the muscles by phosphorolysis and hydrolysis
23. Glycogen has
a) α-1,4 linkage
b) α-1,6 linkages
c) *α-1,4 and α-1,6 linkages
d) α-1,4 and β-1,6 linkage
Lipids
1. The key enzyme in the regulation of fatty acid synthesis is
a) acetyl CoA carboxylase
b) AMP activated proteinkinase
c) *protein phosphatase
d) ATP
21
2. Arachidonate has 20 carbon atoms with
a) double bonds
b) 2 double bonds
c)*AMP activated proteinkinase
d)4 double bonds
3. In the intestine, the dietary fats are hydrolysed by
a)
b)
c)
d)
triacylglycerol lipase
*adenylate cyclase
pancreatic lipase
protein kinase
4. HDLs are synthesized in
a) Blood
b) *liver
c) Intestine
d) pancreas
5. Triacylglycerols are
a) soluble in water
b) *insoluble in water
c) soluble in water at elevated temperature
d) partially soluble in water
6. Animals cannot convert fatty acids into glucose because
a) *acetyl CoA can not be converted to pyruvate
b) absence of malate synthase
c) absence of dehydrogenase
d) absence of a-ketoglutarate dehydrogenase
7. In fatty acid breakdown occurs in
a) *mitochondrial matrix
b) cytosol
c) cell membrane
d) endoplasmic reticulum
8. Cholesterol is essential for normal membrane functions because it
a. Cannot be made by higher organisms, e.g. mammals;
b. Spans the thickness of the bilayer;
c. Keeps membranes fluid;
d)*Catalyzes lipid flip-flop in the bilayer,
9. Which of the following is not essential fatty acid?
a.
b.
c.
d.
* Oleic acid
Linoleic acid
Arachidonic acid
Linolenic acid
22
10. 1 molecule of palmitic acid on total oxidation to CO2 will yield molecules of ATP (as high
energy bonds):
a. * 129
b. 154
c. 83
d. 25
11. Cholesterol is present in all of the following except
a. Egg;
b. Fish ;
c. Milk ;
d. * Pulses,
12. Fatty acids break down of eukaryotes occurs in:
a) *mitochondrial matrix
b) cell membrane
c) cytosol
d) endoplasmic reticulum
13. Very Low density lipids are synthesized in:
a) Blood
b) *Liver
c) intestine
d) pancreas
14. Chylomicrons are synthesized in:
a) Blood
b) Liver
c) *intestine
d) pancreas
15. How many types of lipoproteins are there?
a) 2
b) 8
16. Fatty acid synthesis takes place in
a) Mitochondria
b) Mitochondria
c) 6
d) *5
c) *cytosol
d) endoplasmic reticulum
17. Arachidonic acid contains the number of double bonds:
a. 2
b. 3
c. * 4
d. 5
18. Bile is produced by
a. * Liver
b. Gall-bladder
c. Pancreas
23
d. Intestine
19. Depot fats of mammalian cells comprise mostly of
a) Cholesterol
b) Cholesterol esters
c) * Triacyl glycerol
d) Phospholipids
20. How many ATPs are formed during complete oxidation of palmitate?
a) 35
c) *129
b) 96
d) 131
21. How many classes of steroid hormones are there?
a) 3
c) 4
b) *2
d) 5
22. The number of water molecules consumed by the formation of phosphatidyl serine are
a) 0
c) 1
b) 2
d) *4
23. Synthesis of fatty acid takes place when
a) *fatty acid are plentiful
b) carbohydrate is plentiful
c) carbohydrate and energy are plentiful
d) none of these
24. Fatty acids are activated to acyl CoA by the enzyme thiokinase:
i.
ii.
iii.
iv.
*NAD+
NADP+
CoA
FAD+
TGA – cycle
1. How many molecules of ATPs are synthesized per NADH oxidation?
a) 2
b) 3
c) *1
d) 4
2. In synthesis of Triglyceride from Glycerol 3-phosphate and acetyl CoA, the first
intermediate formed is
a. α-diacyl glycerol
b. *Acyl carnitine
c. Monoacyl glycerol
d. Phosphatidic acid
3. In what form does the product of glycolysis enter the TCA cycle?
24
a) *AcetylCoA
b) NADH
с) Pyruvate
d) Glucose
4. Malate-asparatate shuttle operates in
a) lungs and liver
c) pancreas and liver
b) *heart and liver
d) none of these
5. Oxidation of a molecule involves
a) gain of electron
b) *loss of electron
c) gain of proton
d) loss of proton
6. During cellular respiration, most of the ATP made, is generated by
a) *oxidative phosphorylation
b) photophosphorylation
c) glycolysis
d) substrate-level phosphorylation
7. Cholesterol is transported from liver to extrahepatic tissues by
a. Chylomicrons ;
b. VLDL;
c. HDL;
d. * LDL,
8. The enzymes of the TCA cycle in a eukaryotic cell are located in the
a) Nucleus
c) plasma membrane
b) *Mitochondria
d) lysosomal bodies
9. Citric acid cycle occurs in
a) Cytoplasm
b) *Mitochondria
c) endoplasmic reticulum
d) golgi bodies
10. Most multi-cellular organisms obtain energy for the synthesis of ATP during
oxidative phosphorylation from
a) high energy phosphate compounds
b) *a proton gradient across the inner mitochondrial membrane
c) a proton gradient across the cell membrane
d) a proton gradient across the outer mitochondrial membrane
11. Standard redox potential for a substance is measured under standard condition and
is expressed as
a) mili-Ampere
b) *without unit
c) Volt
d) Ohm
12. Most of the enzymes of the citric acid cycle in a eukaryotic cell are located in the
a) inner mitochondrial membrane
b) *cytosol
c) mitochondrial matrix
d) intermembrane space
13. A positive redox potential means substance has
25
a) lower affinity for electron
b) higher affinity for electron
c) *lower affinity for proton
d) higher affinity for proton
14. Like plasmologens, sphingolipids are found in relative abundance in
a. Bacteria
b. Plant cells
c. * Nerve cells
d. Intestinal cells
15. Lipase can act only at pH:
a. 2.5–4
b. 3.5–5
c. 4 to 5
d. * 5–7
16. Lipase present in the stomach cannot hydrolyze fats owing to
a. Alkalinity
b. Acidity
c. * High acidity
d. Neutrality
17. Fatty acids from hyaloplasm to mitochondria are transported with the help of:
a. * Albumins,
b. Chylomicrons;
c. Alfa- lipoproteins;
d. Pre-D-lipoproteins;
18. The first intermediate in TCA cycle is
a) Succinate
c) *citrate
b) Fumerate
d) malate
19. Cholesterol can be synthesized de novo in
a) Pancreas
b) Intestine
c) *liver
d) cell membrane
20. Hormone, which increase the activity of lipolysis in fatty tissue:
a. * Epinephrine,
b. Parathyroid hormone ;
c. Insulin;
d. Vasopressin ;
21. Which one is not the main protein in electron transport chain?
a) NADH dehydrogenase
c) Cytochrome oxidase
b) Cytochrome bc1 complex
d) *Citrate synthease
22. How many ATPs are produced during citric acid cycle?
a) 10
b) 13
c) 12
d) *8
23. The FADH2 and NADH produced by the oxidation of one acetyl-CoA results in the
synthesis of abouta) 3 ATPs
b) 6 ATPs
c) *11 ATPs
d) 15 ATPs
26
24. How many enzymes are there in the palmitate synthase multiferment complex?
a. * 5,
b. 2;
c. 3 ;
d. 10;
25. The catabolism of sugars and fatty acids is similar because
a) *both of these compounds are funnelled through the TC A/citric acid cycle
b) both of these compounds generate redox energy during catabolism
c) both of these compounds generate chemical energy during catabolism
d) all of the above
metabolism of Amino acid
1. Histidine is degraded to α-ketoglutarate and is described as a
a) gluco amino acid
b) *glucogenic amino acid
c) ketogenic amino acid
d) keto-gluco amino acid
2. Which of the following amino acids is considered as both ketogenic and glucogenic?
a) *Valine
b) Tryptophan
c) Lysine
d) Ornitine
3. Which of the following molecules will be formed from the carbon skeleton of a
ketogenic amino acid?
a. * Acetyl-CoA,
b. Oxaloacetate ;
c. Pyruvate;
d. Ketoglutarate;
4. Which of the following is the best described glucogenic amino acid?
a) Lysine;
b) Tryptophan;
c) *Valine,
d) alanine;
5. Patient has the diagnosis “malignant carcinoid”, amount of serotonine in blood
6.
a)
b)
c)
d)
increased greatly. Name amino acid, able to form the given biogenic amine:
a. Alanine ;
b. * 5-oxytryptophane,
c. Leucine;
d. Threonine;
Oxidative deamination is the conversion of an amino
group from an amino acid to a keto acid
acid to a carboxylic acid plus ammonia
*acid to a keto acid plus ammonia
group from an amino acid to a carboxylic acid
7. An example of a transamination process is
a) glutamate = hexanoic acid + NH3
27
b) aspartate + hexanoic acid = glutamate + oxaloacetate
c) *aspartate + α ketoglutarate = glutamate + oxaloacetate
d) glutamate = α-ketoglutarate + NH3
8. GABA (gamma aminobutyric acid), which belongs to inhibiting mediators of central
nervous system, is a product of glutamic decarboxylation. What vitamin prescription is
appropriate by convulsive state, caused by decrease if GABA formation?
a)B1;
b)B9;
c)* B6,
d)B5;
9. The most toxic compounds is
a) tyrosine
b) *phenylpyruvate
c) lysine
d) phenylalanine
10. In small intestine trypsin hydrolyzes peptide linkages containing
A. * Arginine
B. Histidine
C. Serine
D. Aspartate
11. Tyrosine is degraded to acetoacetyl CoA and fumarate and is described as a
a) glucogenic amino acid
b) ketogenic amino acid
c) *ketogenic and glucogenic amino acid
d) keto-gluco amino acid
12. Transaminase enzymes are present in
a) *liver
c) intestine
b) pancreas
d) kidney
13. A person with phenylketonuria will convert
a) *phenylalanine to phenylpyruvate
b) phenylalanine to isoleucine
c) phenylpyruvate to phenylalanine
d) tyrosine to phenylalanine
14. An example of the oxidative deamination is
a) glutamate = hexanoic acid + NH3
b) aspartate + α-ketoglutarate = glutamate + oxaloacetate
c) *glutamate = α-ketoglutarate + NH3
d) aspartate + hexanoic acid = glutamate + Oxaloacetate
15. In the normal breakdown of phenylalanine, it is initially degraded to
a) fumarate
b) *tyrosine
c) lysine
d) phenylpuruvate
28
16. Transamination is the transfer of an amino
a) acid to a carboxylic acid plus ammonia b) *group from an amino acid to a keto acid
c) acid to a keto acid plus ammonia
d) group from an amino acid to a carboxylic acid
17. Lysine is degraded to acetoacetyl-CoA and is described as a
a) *ketogenic amino acid
b) glucogenic amino acid
c) keto-gluco amino acid
d) glico-glucogenic amino acids
18.A ketogenic amino acid is one which degrades to
a) keto-sugars
b) either acetyl CoA or acetoacetyl CoA
c) pyruvate or citric acid cycle intermediates
d) * multiple intermediates including pyruvate or citric acid cycle intermediates and
acetyl CoA or acetoacetyl CoA
19. A best described ketogenic amino acid is
a) * lysine
b) tryptophan
c) valine
d) alanine
20. A person suffering from phenylketonuria on consumption food containing high
phenylalanine may lead to the accumulation of
a) phenylalanine
c) tyrosine
b) *phenylpyruvate
d) isoleucine
DNA structure and replication
1. The accepted hypothesis for DNA replication is
a) conservative theory
b) dispersive theory
c) *semi-conservative theory
d) evolutionary theory
2. When DNA polymerase is in contact with guanine in the parental strand, what does it
add to the growing daughter strand?
a) Phosphate
b) *Cytosine
c) Uracil
d) Guanine
3. Telomeres are usually rich in which nucleotide?
a) Adenine
b) *Guanine
c) Thymine
d) Cytosine
4. Which is the largest among the followings?
a) *Nucleotide
c) Phosphate
b) Nitrogenous base
d) Carbon
5. The chromosomal DNA complexes with
a) three types of histone as H1, H2A and H4
b) * five types of histone as H1, H2A, H2B, H3 and H4
c) four types of histone as H1, H2A, H3 and H
29
d) two types of histone as H1 and H4
6. Adenine is
a) * 6-Amino purine
b) 2-Amino-6-oxypurine
c) 2-Oxy-4-aminopyrimidine
d) 2, 4-Dioxypyrimidine
7. In DNA double helix, the two DNA chains are held together by
a) covalent bonds between the pair of bases
b) *hydrogen bonds between the pair of bases
c) ionic bonds between the pair of bases
d) covalent-ionic bonds
8. The 5' and 3' numbers are related to the
a) length of the DNA strand
b) *carbon number in sugar
c) the number of phosphates
d) the base pair rule
9. Messelsen and Stahl model of replication was called
a) conservative replication
b) *semi-conservative replication
c) the number of phosphates
d) the base pair rule
10. The most common liquid volumes in molecular biology are measured in
a) ml
b) * μl
c) nl
d) 1
11. DNA replication takes place in which direction?
a) 3' to 5'
b) *5 'to 3'
c) Randomly
d) Vary from organism to organism
12. DNA gyrase in E. coli
а) adds positive supercoils to chromosomal DNA
b) *can be inhibited with antibiotics
c) is required only at the site
d) performs the same function as helicase in eukaryotes
13. In DNA, there are
а) five bases known as adenine, guanine, thymine, tryptophan and cytosine
b) *four bases known as adenine, guanine, thymine and cytosine
c) three bases known as adenine, guanine and cytosine
d) only two bases known as adenine and cytosine
14. In DNA, guanine pairs with
a) Adenine
c) Thymine
b) *Cytosine
d) Uracil
15. REMOVED
30
16. An enzyme of pyrimidine nucleotides biosynthesis regulated at the genetic level by
apparently coordinate repression and derepression is
a) * Carbamoyl phosphate synthetase
b) Dihydroorotate dehydrogenase
c) Thymidine kinase
d) Deoxycytidine kinase
17. Aspartate contributes the following carbon atoms of the pyrimidine nucelus:
A. C2 and C4
B. C5 and C6
C. C2, C4 and C6
D. * C4, C5 and C6
18. What is the approximate size (in kb) of the E. coli genome?
a) 3000 kilobase
b) *4500 kilobase
c) 5500 kilobase
d) 6500 kilobase
19. In the study of one experiment it was found that the value of Tm for DNA is = 40° C. If
the cell has 20% GC at the above Tm, then what will be value of 'Tm' if the GC%
increases to 60%?
a) Remains same
b) *Increases
c) Decreases
d) Can not be compared
20. What is the range of melting point temperatures (Tm) for most DNA molecules?
a) 50 to 60°C
b) 60 to 80°C
c) 70 to 90°C
d) *80 to l00°C
21. The overall conclusion of the Hershey-Chase experiment was that
a) *DNA was responsible for heredity
b) proteins and DNA were responsible for heredity
c) the ratio of Adenine to thymine was always the same
d) phage DNA was similar to bacterial DNA
22. A cesium chloride will separate DNA molecules by
a) absorption
b) restoration
c) *density
d) adhesion
23. If one cell has AT contents 40%, what will be the percentage of Guanine residue?
a) *60%
b) 15%
c) 30%
d) Guanine residue can not be calculated
24. Which of the following enzyme adds complementary bases during replication?
a) Helicase
b) Synthesase
c) Replicase
d) *Polymerase
25. Which DNA polymerase removes RNA primers in DNA synthesis?
a) *Polymerase I
b) Polymerase II
c) Polymerase III
d) none of these
26. Enzymes, responsible for unraveling short segments of DNA is
a) *DNA polymerase
b) helicase
c) DNA ligase
d) primase
31
27. Enzyme, responsible for proofreading base pairing is
a) *DNA polymerase
b) Telomerase
c) Primase
d) DNA ligase
28. Which of the following would not contain DNA?
a) Yeast
b) Bacteria
c) *Glass crystals
d) Mold
29. The nucleosome consists of histone
a) *octamer and 146 bp of DNA
c) hexamer and 146 bp of DNA
b) tetramer and 146 bp of DNA
d) tetramer and 146 bp of RNA
30. What bands will be observed in a cesium chloride gradient after two rounds of
replication?
a) One light, one medium and one heavy band
b) *One light and one medium band
c) One medium band
d) One medium and one heavy band
31. Proteins involved in opening a replication bubble are
a) DNA helicases
b) single stranded binding proteins
c) ligase
d) *DNA topoisomerase
32. What is the main damaging effect of UV radiation on DNA?
a) Depurination
b) *Formation of thymine dimers
c) Single strand break
d) Dehydration
33. Removed
34. DNA helicase is used to
a) *unwind the double helix,
c) break a phosphodiester bond in DNA strand;
b) interact the double helix closely,
d) break a phosphodiester bond in
RNA strand,
35. E.coli DNA polymerases II and III lack
a) *5' → 3' exonuclease activity
b) 5' → 3' endonuclease activity
c) partially 5' → 3' exonuclease activity
d) partially 5' → 3' endonuclease activity
36. In sperm heads, DNA is particularly highly condensed and the histones are replaced
with small basic protein called
a) *protamines
b) purines
c) pyrimidines
d) all of the above
37. DNA can be sequenced by the
a) chemical method
b) chain termination procedure
c) *chemical method and chain termination proced
d) physical method
32
RNA Structure and replication
1. A nicked RNA molecule can be ligated by
a) T4 RNA ligase
b) DNA polymerase
c) *T4 DNA ligase
d) DNA polymerase II
2. Which of following RNA characteristically contains unusual purines and pyrimidmes?
a) rRNA
b) nRNA
c) mRNA
d) *tRNA
3. The anticodon is a structure on
а) m-RNA.
b) * t-RNA
c) ribosome
d) r-RNA
4. The genetic material of retroviruses such as HIV is
а) DNA
b) *RNA
c) protein
d) r-RNA
5. Retroviruses replicate via __________ intermediate
а) RNA
b) *DNA
c) mRNA
d) r-DNA
6. During RNA synthesis, the DNA template sequence 5'Tp Ap Gp Cp 3' Would be
transcribed to produce which of the following RNA sequence?
а) 5'-Ap Tp Cp Gp-3'
b) *5'-Gp Cp Up Ap-3'
c) 5'-Gp Cp Tp Ap-3'
d) 5'-Ap Up Cp Gp-3'
7. RNA instability in alkaline solutions is due to
а) adenine
b) *ribose
c) uracil
d) single strand natur
8. In RNA, uracil pairs with
а) *adenine
c) thymine
b) cytosine
d) guanine
9. Two features of the tRNA molecule associated, in converting the triplet codon to an
amino acid, are
а) in the T Loop and D stem and loop;
b) in the anticodon loop and D stem loop;
c) *in the anticodon loop and the 3' CCA en,
d) in the aodon loop and D stem loop;
10. Which of the following is the smallest of the RNAs?
а) Messenger RNA
b) *Transfer RNAs
c) Ribosomal RNAs
d) Ribosomal DNAs
11. The mRNA from which of the following would contain a poly-A tail?
а) A restriction endonuclease from E. coli b) Bacterial alpha-amylase
33
c) *Human insulin
d) Bacteriophage DNA ligase
12. What is the average size (in bp) of a mature t-RNA?
а) *80 bp
b) 100 bp
c) 120 bp
d) 140 bp
13. What modified base is at the 5' extremity of a capped eukaryotic m-RNA?
а) 1-methyl-adenosine
b) 2'-O-methyl-guanosine
c) *7-methyl-guanosine
d) 1-methyl-guanosine
14. What is the function of messenger RNA?
а) It carries amino acids
c) *It is a direct copy of a gene
b) It is a component of the ribosomes
d) It is the genetic material of some organisms
Protein Synthesis
1. On the ribosome, mRNA binds
a) between the subunits;
b) to the large subunit;
c) *to the small subunit,
d) large and small subunit;
2. Type I proteins (plasma membrane) have are:
a) *cleavage N- terminal signal sequence and a hydrophobic stop transfer sequence
b) cleavaged N- terminal signal sequence that doubles as the membrane anchoring
sequence
c) multiple signal sequence and a hydrophobic stop transfer sequence
d) multiple signal sequence that doubles as the membrane anchoring sequence
3. A polysome could be best described as
а) an active site of DNA synthesis;
c) an active site of lipid synthesis;
b) *an active site of protein synthesis,
d) ) an active site of RNA synthesis;
4. Eukaryotic mRNA binding to the ribosomes is facilitated by __________
а) the Shine Dalgarno sequence
b) *the 7-methyl guanosine cap
c) tRNA
d) poly A tail
5. Amino acids are joined together into a protein chain by which of the following?
а) *Transfer RNA
b) DNA polymerase
c) Hydrogen bonds
d) Messenger RNA
6. Phosphorus is taken up by the cell during the process of
а) carbohydrate synthesis.
b) protein synthesis,
c) lipid synthesis
d) *ATP synthesis
7. Protein synthesis rates in prokaryotes are limited by the rate of mRNA synthesis. If RNA
synthesis occurs at the rate of 50 nucleotides/sec, then rate of protein synthesis occurs at
34
а) 10 amino acids/sec
c) 25 amino acids/sec
8. The site of protein synthesis is
а) *Ribosome
c) Endoplasmic reticulum
b) *17 amino acids/sec,
d) 50 amino acids/sec
b) Nucleus
d) Chromosome
9. The structure in a bacterium that indicates an active site for protein synthesis is
а) a chromosome
b) a cell membrane
c) a flagellum
d) *a polysome
10. The lac operon contains the z, y and a structural genes ___________________________
а) *encoding p-galactosidase, galactose permeases and thio-galactosidase transacetylase
respectively,
b) encoding p-galactosidase and galactose permeases;
c) encoding P-galactosidase only;
d) encoding L-galactosidase only;
11. Which of the following is not necessary for protein synthesis to occur, once
transcription is completed?
а) tRNA
b) Ribosomes
c) mRNA
d) *DNA
12. Ribosomes select the correct tRNAs
а) then bind to the appropriate mRNA
b) *solely on the basis of their anticodons
c) depending on their abundance in the cytosol
d) with the least abundant anticodons
13. Sigal peptide protein removal that is translocated across a membrane is accomplished
by
а) f-Met aminopeptidase
b) trypsin
c) *signal peptidase
d) chymotrypsin
14. The direction of amino acid transfer to the growing polypeptide chain is
а) from the A (aminoacyl tRNA site) site to the P (peptidyl tRNA site) site on the
ribosome
b) *from the P site to the A site on the ribosome
c) from the A site to the E (exit tRNA site) site on the ribosome
d) from the P site to the E site on the ribosome
15. The pathway of a tRNA during polypeptide elongation on the ribosome is
а) *A site → P site → E site
b) P site → entry site → exit site
c) A site → P site → entry site
d) P site → A site → E site
16. Which of the following has unusual bases?
а) mRNA
b) *tRNA
c) rRNA
d) hnRNA
35
17. The site on a bacterial chromosome that marks the termination point for chromosome
replication is called
а) * ter
b) a stop codon.
c) a stem-loop
d) pau
18. Degenerated codon differs mostly in
а) the identities of their second base
b) the identities of their third base
c) the wobble position
d) *the identities of their third base and wobble position
19.Translation in prokaryotes begins by the formation of a 30S initiation complex between
the
а) *30S ribosomal subunit, mRNA, initiation factors and N-fMet tRNA
b) 30S ribosomal subunit, tRNA and initiation factors
c) 30S ribosomal subunit and mRNA only
d) 30S ribosomal subunit, mRNA and initiation factors
20. The anticodon of tRNA
а) binds to rRNA NA
b) binds to an amino acid
c) binds to the Shine Dalgarno sequence
d) * binds to an mRNA codon
21. NH3 is detoxified in brain chiefly as
a)* Urea,
b)Uric acid;
c)Creatinine;
d)Glutamine;
22. Processive synthesis is a characteristic feature of
а) all DNA polymerases
c) removal of RNA primers on Okasaki fragments
b) *DNA Pol III at a replication fork
d) DNA mismatch repair
23. Which site of the tRNA molecule binds to the mRNA molecule?
а) *Anticodon
b) Codon
c) Amino acid
d) 5 prime end
24. The first step in translation is
a) binding of the two ribosomal subunits to each other
b) binding of mRNA to the two ribosomal subunits
c) binding of tRNA to the small ribosomal subunit
d) *binding of mRNA to the small ribosomal subunit
25. Which of the following amino acid starts all proteins synthesis?
а) Glycine
b) Proline
36
c) Thymine
d) *Methionine
26. The growing polypeptide chain is released from the ribosomes when
а) a* chain terminating codon is reached
b) a chain terminating tRNA binds to the ribosome
c) the 7-methyl guanosine cap is reached
d) the poly A tail is reached
27. Which of the following RNAs bind to an amino acid?
а) * mRNA
b) tRNA
c) rRNA
d) hnRNA
28. How many bases of nucleic acid determine a single amino acid?
а) Four
b) One
c) Two
d) *Three
29. The ribosomes are composed of
а) proteins
c) *proteins and RNA
b) RNA
d) lipids
30. Which is required for protein synthesis?
а) tRNA
c) rRNA
b) mRNA
d) * tRNA, rRNA, mRNA
Genetic Code and Regulation
1. Which of the following techniques was carried out by Nirenberg and Matthaei in 1961 to
determine the first codon?
а) *In vitro synthesis of a polypeptide using UUUUU,
b) Labeled peptide binding to a ribosome;
c) Mixed co-polymer mRNA synthesis;
d) Mixed polymer mDNA synthe;
2. Bacterial protein called catabolic activator protein (CAP) is an example of
а) negative control of gene expression;
b) on;
c) *second type of positive control of gene expression;
d) second type of positive control of gene expression;
3. How many different codons are possible?
а) 3;
b) 20;
c) *64,
c) An infinite number;
4. The genetic code is
а) universal;
b) *universal except for rare exceptions in mitochondria and some protozoa
c) species-specific;
d) kingdom-specific;
37
5. Which of the following has been used as an evidence that primitive life forms lacked both
DNA and enzymes?
а) *RNA can both code genetic information and act as a catalyst,
b) DNA and enzymes are only present in the most advanced cells;
c) Advanced cells lack RNA;
d) kingdom-specific;
6. Crick demonstrated that the genetic code involved three bases and suggested that the
code was degenerated. What experimental technique Crick conducted to suggest genetic
code degeneration?
а) Gel electrophoresis ;
b) Density gradient centrifugation;
c) *Frameshift mutagenesis,
d) Restriction digests of the rII gene;
7. Codon that specify the amino acids often differs in the
а) first base;
b) second base;
c) *third base,
c) fife base;
8. The genetic code is degenerated. Which of the following codons represents the principle
of degeneracy?
а) UAA and UAC;
b) AUG and AUA;
c) *CAU and CAC,
d) UUA and UUC,
9. How many amino acids will be encoded by 5' GAU GGU UGA UGU 3' sequence?
а) One;
b) *Two,
c) Three;
d) Four;
10. In protein synthesis in prokaryotes
а) *the initiating amino acid is N- formyl methionine,
b) the initiating amino acid is methionine ;
c) the initiating amino acid is phenyl alanine;
d) initiating amino acid is alanine;
11. AUG codes for methionine act as a
а) *initiation code,
c) termination code;
b) elongation code;
d) propagation code;
12. Translation begins
а) at the replication fork;
c) *at the start codon,
b) on the lagging strand;
d) in nucleus;
Biochemistry : Transcription and Regulation
1. The complex of RNA polymerase, DNA template and new RNA transcript is called
а) *transcription bubble,
b) replication bubble;
c) a translation bubble;
d) translation and replication bubble;
2. RNA polymerase in prokaryotes has a removable
38
а) *alpha subunit,
c) beta and sigma;
b) beta subunit;
d) sigma subunit;
3. Rho-dependent termination of transcription in E. coli
а) requires ATP;
b) requires about 50 nucleotides of uncomplexed mRNA;
c) *requires ATP and requires about 50 nucleotides of uncomplexed mRNA,
d) removes mRNA and holoenzyme from the DNA;
4. Transcription by E. coli polymerase occurs in
a) four phases known as initiation, propagation, elongation and termination;
b) *three phases known as initiation, elongation and termination,
c) two phases known as initiation and termination;
d) as initiation, propagation;
5. Which of the following is necessary for transcription to occur?
а) DNA molecule;
b) RNA polymerase;
c) DNA polymerase;
d) *Both DNA & RNA polymerase,
6. Each tRNA molecule has a cloverleaf secondary structure consisting of
а) *three stem loop,
b) two stem loops;
c) four stem loops;
d) fife stem loops;
7. The function of the sigma factor of RNA polymerase is to
а) *assure that transcription begins at the proper point,
b) assure that transcription ends at the proper point;
c) assure that translation begins at the proper point;
d) assure that translation ends at the proper point;
8. In both eukaryotes and prokaryotes, a promoter region that is rich in AT bases is called
as
а) CATT;
b) Shine Dalgarno region;
c) *TATA box,
d) SV40 region;
9. The RNA polymerases that transcribe bacterial DNA are
а) *multisubunit enzymes,
b) only active inside the cell;
c) interchangable with DNA polymerases; d) highly glycosylated in their active forms;
ENZYMES
1. Which of the following statements about enzymes or their function is true?
a) Enzymes do not alter the overall change in free energy for a reaction;
b) *Enzymes are proteins whose three-dimensional form is key to their function,
c) Enzymes speed up reactions by lowering activation energy;
d) Enzymes speed up reactions by lowering not energy;
2. Tryprotophan synthetase of E.coli, a typical bifunctional oligomeric enzyme consist
of
a) a protein designated A;
b) *two proteins designated A and B,
39
c) a protein A and one-subunit a;
d) a protein designated B;
3. What is the specificity of the Clostripain protease?
a)
b)
c)
d)
*It cleave after Arg residues;
It cleave after His residues;
It cleave after Lys residues;
It cleave after Ala residues;
4. The proteolysis rate enhancement by chymotrypsin (~1010 folds) corresponds to a
reduction in activation energy of about
a) 40 kJ/mol;
c) *58 kJ/mol,
b) 49 kJ/mol;
d) 88 kJ/mol;
5. Which of the following is false statement with regard to comparison between Serine
and HIV proteases?
a) Both use nucleophilic attack to hydrolyze the peptide bond;
b) Both require water to complete the catalytic cycle;
c) *Both forms an acyl-enzyme intermediate,
d) Both show specificity for certain amino acid sequences;
6. In the enzyme-catalyzed reaction shown below, what will be the effect on substances
A, B, C, and D of inactivating the enzyme labeled E2?
A ---(E1)---> B ---(E2)---> C ---(E3)--->
a) A, B, C, and D will all still be produced;
b) A, B, and C will still be produced, but not D;
c) *A and B will still be produced, but not C or D,
d) A will still be produced, but not B, C, or D;
7. The nucleophile in serine proteases is
a) Serine;
c) *Serine and water,
b) water;
d) Asparagine;
8. The role of Asp 102 and His 57 during trypsin catalysis is to
a) neutralize the charge on the other's side chain;
b) *keep the specificity pocket open,
c) function as a proton shuttle;
d) clamp the substrate into the active site;
9. The cleavage specificity of trypsin and chymotrypsin depend in part on the
a)
b)
c)
d)
proximity of Ser 195 to the active site or specificity pocket;
*size, shape, and charge of the active site or specificity pocket;
presence of a low-barrier hydrogen bond in the active site or specificity pocket;
absence of water in the active site;
10. The E.coli pyruvic acid dehydrogenase complex is reported to
40
a) decatalyze the oxidation of pyruvic acid to acetyl Co A and CO2;
b) *Catalyze the oxidation of pyruvic acid to acetyl Co A and CO2,
c) retard the reduction of pyruvic acid to acetyl Co A and CO2;
d) Catalyze the reduction of pyruvic acid to acetyl Co A and CO2;
11. Before they can react, many molecules need to be destabilized. This state is typically
achieved through
a) changing the three-dimensional shape of the molecule;
b) oxidizing the molecules by removing electrons;
c) changing the reaction from a biosynthetic to a catabolic pathway;
d) *the input of a small amount of activation energy,
*Answers to exam test
1. Proteins
1-b, 2-a, 3-a, 4-d, 5 –d, 6-c, 7-c, 8-a, 9 –c, 10-c.
2. Aminoacids
1-b, 2-b, 3-c, 4-c, 5 –c, 6-c, 7-c, 8-c, 9 –a , 10-a , 11-c, 12-d, 13-b, 14-b, 15-a, 16-a, 17-a, 18-d,
19-b, 20-c, 21-c, 22-a, 23-b, 24-c, 25-b, 26-c, 27- b, 28-d.
3. Nucleic acid
1-а, 2-с, 3-d, 4-d, 5 –d, 6-a, 7-b, 8-c, 9 –c, 10-c.
4. Vitamins
1-c, 2-d, 3-c, 4-b, 5 –b, 6-b, 7-c, 8-b, 9 – b, 10-b , 11-c, 12-c, 13-d, 14-b, 15-d, 16-a, 17-c, 18b, 19-d, 20-d, 21-a, 22-a, 23-b, 24-d, 25-b, 26-c, 27- b, 28-c, 29-a, 30-a,31-c, 32-b, 33-b, 34b, 35-a, 36-c, 37-a, 38-a, 39-d, 40- d, 41-c, 42-a, 43-d, 44-d, 45-b, 46-c, 47-c, 48-a, 49-c, 50c, 51-a, 52-c, 53-c, 54-a, 55-a, 56-a, 57-d, 58-c, 59-c, 60-d, 61-d, 62-b.
Carbohydrate
1-d
2 –c
3–d
4–b
5–b
36 – c
6-c
11 – d
7–c
12 – d
8–c
13 – b
9–b
14 – b
10 –b
15 – c
37 – d 38 - a
16 – b
17 – d
18 – d
19 – a
20 – d
5. Glycolis
1-d
2–a
3–a
6-b
7–c
8–a
11 – b
12 – c
13 – b
21- b
22- a
23 – a
24 – c
25 – a
16 – d
17 – c
18 – c
26 – b
27 – d
28 – c
29 – b
30 – c
31 – a
32 – c
33 - b
34 - c
35 – d
21- d
22- d
23 – c
41
4–c
5–b
9–b
10 – c
14 – c
15 – d
19 – d
20 – c
6. Lipids
1-c
2 –c
3–b
4–b
5–b
6- a
7–a
8–d
9–a
10 –a
11 – d
12 – a
13 – b
14 – c
15 – d
16 – c
17 – c
18 – a
19 – c
20 – c
21- b
22- d
23 – a
24-a
7. TGL cycle
1-c
2 –b
3–a
4–b
5–b
6-a
7–d
8–b
9–b
10 –b
11 – b
12 – b
13 – c
14 – c
15 – d
16 – c
17 – a
18 – c
19 – c
20 – a
21- d
22- d
23 – c
24 – c
25 – a
8. Metabolism of amino acids
1-b
6-c
11 – c
2 –a
7–c
12 – a
3–a
8–c
13 – a
4–c
9–b
14 – c
5–b
10 –a
15 – b
16 – b
17 – a
18 – d
19 – a
20 – b
9. DNA – structure and replication
1-c
6-a
11 – b
16 – a
21- a
2 –b
7–b
12 – b
17 – d
22- c
3–b 8–b
13 – b
18 – b
23 – a
4–a 9–b
14 – b
19 – b
24 – d
5 – b 10 –b
15 – d
20 – d
25 – a
26 – a
27 – a
28 – c
29 – a
30 – b
31 – d
32 – b
33 – d
34 – a
35 – a
36- a
37 - c
10. RNA - structure and replication
1-c
6-b
11 – c
2 –d
7–b
12 – a
3–b
8–a
13 – c
4–b
9–c
14 – c
5–b
10 –b
11. Protein synthesis
1-c
6-d
11 – d
2 –a
7–b
12 – b
3–b 8–a
13 – c
4–b
9–d
14 - b
5 – a 10 –a
15 – a
16 – b
17 – a
18 – d
19 – a
20 – d
21- a
22- b
23 – a
24 – d
25 – d
26 – a
27 – a
28 – d
29 – c
30 – d
12. Genetic code and regylation
1-a
6-c
42
2 –c
3–c
4–b
5–a
7–c
8–c
9–b
10 –a
11 – a
12 – c
13. Transcrinption and regylation
1-a
6-a
2 –a
7–a
3–c
8-c
4–b
9–a
5–d
14. Enzymes
1-b
4-c
7–c
2 –b
5–c
8–b
3–a
6–c
9–b
10- b
11- d
43