BIO 110 – INTRODUCTION TO BIOLOGY

MULTIPLE CHOICE QUESTIONS

{Carbohydrates, amino acids, proteins, central dogma of the cell, DNA and RNA}

“CARBOHYDRATE”.

1. Carbohydrates are also known as___________

a) Hydrates of carbon
b) Carbonates
c) Glycolipids
d) Polysaccharides

Answer: a
Explanation: Basically, carbohydrates are polyhydroxy aldehyde or ketones, or compounds
that can be break down to them. Mostly carbohydrates contain hydrogen and oxygen in the
same ratio as in water, hence it is also called as hydrates of carbon.

2. Class of carbohydrate which cannot be hydrolyzed further, is known as?

a) Disaccharides
b) Polysaccharides
c) Proteoglycan
d) Monosaccharide

Answer: d
Explanation: Monosaccharides are single polyhydroxy aldehyde or ketone unit with general
formula CnH2nOn. These are simple sugars which cannot be hydrolyzed further in a simpler
form.

3. Which class of carbohydrates is considered as non-sugar?

a) Monosaccharides
b) Disaccharides
c) Polysaccharides
d) Oligosaccharides

Answer: c
Explanation: When hundreds or thousands of monosaccharides condense together, it will
form polysaccharides. These are not sweet in taste hence they are called non-sugars.

4. Sugars which differs from each other only around single carbon atom is called
epimer.
a) True
b) False

Answer: a
Explanation: Mostly common sugars are similar, the basic difference among them is at a
single carbon atom i.e. differing by stereochemistry, these types of sugars which differ from
each other only at a single carbon atom are called epimers. For e.g. D-glucose and D-
mannose differ only at second carbon position.

5. A molecule of amylopectin which contains 1500 glucose residues and is branched

after every 30 residues. How many reducing ends are there?
a) 0
b) 1
c) 2
d) 5

Answer: b
Explanation: Correct answer is 1 as no matter how many residues are there but a molecule of
amylopectin has only one reducing end.

6. What is the name of the drug which inhibits Na+/K+ pump across the cell
membrane?
a) Taxol
b) Vinblastine
c) Quinone
d) Ouabain
Answer: d
Explanation: Ouabain is a common glycoside which inhibits the action of enzymes that pump
Na+/k+ ions across cell membranes. Glycosides are formed by condensation between
monosaccharides.

7. Mark the INCORRECT statement about sugar alcohol?

a) Addition of -itol as a suffix
b) A linear molecule that cannot cyclize
c) Carbonyl groups reduced to a hydroxyl group
d) Terminal -OH group oxidizes

Answer: d
Explanation: Sugar alcohol or alditols are formed by reduction of the carbonyl group in
aldoses and ketoses to a hydroxyl group. These are designated by the addition of -itol and are
linear molecules. So, terminal -OH group oxidizes is incorrect.

8. Which of the following amino sugar are present in the bacterial cell wall?
a) N-acetylmuramic acid
b) Sialic acid
c) Aminoglycoside
d) Azide

Answer: a
Explanation: N-acetylmuramic acid is a derivative of glucosamine in which lactic acid is
linked to oxygen at C-3 of N-acetylglucosamine which is a part of many structural polymers.

9. Which of the following glycosidic linkage found in maltose?

a) Glucose (α-1 – 2β) Fructose
b) Glucose (α1 – 4) Glucose
c) Galactose (β1 – 4) Glucose
d) Glucose (β1 – 4) Glucose

Answer: b
Explanation: In maltose, α- anomeric form of C-1 on one sugar and hydroxyl oxygen atom on
C-4 of other sugar are joined by glycosidic linkage. Such linkage is also called the α-1, 4-
glycosidic bond.

10. Which of the following is also known as invert sugar?

a) Sucrose
b) Fructose
c) Dextrose
d) Glucose

Answer: a
Explanation: Sucrose is also known as invert sugar as during hydrolysis of sucrose with hot
dilute acid it produces an equimolar combination of D-glucose and D-fructose. This
phenomenon is also called inversion of sucrose or invertose.

11. Name the major storage form of carbohydrates in animals?

a) Cellulose
b) Chitin
c) Glycogen
d) Starch

Answer: c
Explanation: Glycogen is a carbohydrate which found mostly in liver and muscle of animals
and considered as major storage form. It is highly branched form of amylopectin where
branching occurs after every 10 glucose residues.

“COORDINATED REGULATION OF GLYCOLYSIS AND GLUCONEOGENESIS”.

12. Gluconeogenesis responds to which of the following?

A. Hormonal control
B. pH control
C. Temperature control
D. Blood control

Answer: A
Clarification: When the blood glucose level decreases, the hormone glucagon signals the liver
to produce and release more glucose and to stop consuming it for its own needs. One source
of glucose is gluconeogenesis.

13. When blood sugar levels fall, glycolysis is halted in liver to allow ___________
A. Homeostasis
B. Anaerobic respiration
C. Aerobic respiration
D. Gluconeogenesis

Answer: D
Clarification: Gluconeogenesis produces glucose in order to compensate the fall.

14. How many steps are catalyzed by the same enzymes in both glycolysis and
gluconeogenesis?
A. 6
B. 7
C. 8
D. 9

Answer: B
Clarification: Phosphohexose isomerase, aldolase, triose phosphate isomerase,
glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate
mutase and enolase are the enzymes which catalyze the reactions in both glycolysis and
gluconeogenesis.

15. How many steps are catalyzed by different enzymes in glycolysis and
gluconeogenesis?
A. 2
B. 3
C. 4
D. 5

Answer: B
Clarification: Hexokinase, phosphofructokinase-1 and pyruvate kinase in glycolysis, Glucose
6-phosphatase, fructose 1, 6-bisphosphatase, PEP carboxykinase and pyruvate carboxylase in
gluconeogenesis.

16. Three reactions of glycolysis are so exergonic, which are not catalyzed by?
A. Hexokinase
B. PFK-1
C. Pyruvate kinase
D. Pyruvate dehydrogenase

Answer: D
Clarification: Three glycolytic enzymes are subjected to allosteric regulation: hexokinase IV,
PFK-1 and pyruvate kinase.

17. What are the effects of increased concentration of citrate?

A. Increases the inhibitory effect of ATP
B. Decreases the inhibitory effect of ATP
C. Increases the activity of ATP
D. Increases the activity of AMP

Answer: A
Clarification: Citrate is a key intermediate in the aerobic oxidation of pyruvate, fatty acids
and amino acids. It serves as an allosteric regulator of PFK-1; its high concentration increases
the inhibitory effect of ATP, further reducing the flow of glucose through glycolysis.

18. The second control point in gluconeogenesis is the reaction catalyzed by

___________
A. Pyruvate kinase
B. Pyruvate dehydrogenase
C. FBPase-1
D. PFK-1

Answer: C
Clarification: The second control point in gluconeogenesis is the reaction catalyzed by
fructose 1, 6-bisphosphatase-1.
19. Which of the following statements is true about PFK-1?
A. It is stimulated by AMP and ADP
B. It is stimulated by citrate and ATP
C. It is inhibited by AMP and ADP
D. It is stimulated by citrate and ADP

Answer: A
Clarification: AMP promotes glycogen degradation and glycolysis by activating glycogen
phosphorylase and stimulating the activity of phosphofructokinase-1. ATP and citrate are
allosteric inhibitors.

20. Which of the following statements is true regarding acetyl co-A?

A. It stimulates pyruvate dehydrogenase
B. It stimulates pyruvate carboxylase
C. It inhibits pyruvate carboxylase
D. It stimulates hexokinase

Answer: B
Clarification: Gluconeogenesis is regulated at the level of pyruvate carboxylase which is
activated by acetyl co-A.

21. Which of the following is a potent regulator of glycolysis and gluconeogenesis?

A. Fructose 2, 6-bisphosphate
B. Fructose 1, 6-bisphosphate
C. Fructose 6-phosphate
D. Glucose 1, 6-bisphosphate

Answer: A
Clarification: The hormonal regulation of glycolysis and gluconeogenesis is mediated by
fructose 2, 6-bisphosphate.

22. Fructose is metabolized by

A. fructose 1-phosphate pathway

B. fructose 6-phosphate pathway
C. glyceraldehyde 3-phosphate pathway
D. both (a) and (b)

Answer: D

23. 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

Answer: C

24. Humans are unable to digest

A. starch
B. complex carbohydrates
C. denatured proteins
D. cellulose

Answer: D

25. How many ATP equivalents per mole of glucose input are required for
gluconeogenesis?

A. 2
B. 6
C. 8
D. 4

Answer: B

26. 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

Answer: B

27. Gluconeogenesis requires a higher amount of ATP equivalents as compared to that

produced by glycolysis because

A. gluconeogenesis releases energy as heat

B. glycolysis releases energy as heat
C. glycolysis occurs in the mitochondria while gluconeogenesis occurs in the cytosol
D. all of the above

Answer: B

28. 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. Acts outside the cell to influence cellular processes

Answer: C

29. 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

Answer: C

30. The cells dependent solely on glucose as an energy source are

A. muscle cells
B. brain cells
C. kidney cells
D. liver cells

Answer: B

31. The main site for gluconeogenesis is

A. kidney
B. liver
C. brain
D. muscle

Answer: B

32. 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

Answer: D

33. 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

Answer: D
34. Cellulose fibers resemble with the protein structure in the form of

A. ß-sheets
B. a-helices
C. ß-turns
D. None of these

Answer: A

35. During vigorous exercise, pyruvate produced by glycolysis is converted to

A. acetate
B. lactate
C. monosodium phosphate
D. pyruvic acid

Answer: B

36. Glucagon and epinephrine

A. inhibits gluconeogenesis and stimulates glycolysis

B. stimulates gluconeogenesis and glycolysis
C. stimulates gluconeogenesis and inhibits glycolysis
D. inhibits gluconeogenesis and glycolysis

Answer: C

37. The NAG6 substrate is hydrolyzed by human lysozyme to form

A. 6 glucosamines + 6 acetic acids

B. NAG4 + NAG2
C. NAG3 + NAG3
D. NAG3

Answer: B
38. 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

Answer: D

39. Saliva contains all of the following except

A. hormones
B. amylase
C. bacteria-killing enzymes
D. antibodies

Answer: A

40. 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

Answer: A

41. 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

Answer: D

42. Hydrolysis of lactose yields

A. galactose and fructose
B. galactose and glucose
C. glucose and fructose
D. fructose and galactose

Answer: B

43. 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

Answer: A

44. A catabolic intermediate which stimulates phosphofructokinase would stimulate

A. gluconeogenesis
B. glycolysis
C. glycogen synthesis
D. none of these

Answer: B

45. Pyruvate is initially converted to which of the following in the gluconeogenesis?

A. Glycerol
B. Phosphoenol pyruvate
C. Oxaloacetate
D. Acetyl CoA

Answer: C
46. 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

Answer: A

47. The conversion of pyruvate to lactate is catalysed by

A. pyruvate carboxylase
B. lactate dehydrogenase
C. pyruvate dismutase
D. pyruvate decarboxylase

Answer: B

48. Which of the following can act as precursors for gluconeogenesis?

A. Lactate
B. Glycerol
C. Alanine
D. All of these

Answer: D

49. a-amylose is similar to

A. ß-sheets
B. ß-turned coils
C. a-helices
D. the hydrophobic core

Answer: C
50. Storage polysaccharide made by animals is

A. amylopectin
B. glycogen
C. cellulose
D. collagen

Answer: B

51. The glycosidic bond

A. in maltose is not hydrolyzed in lactose intolerant humans

B. in sucrose is hydrolyzed by bees
C. joins glucose and fructose to form sucrose
D. both (b) and (c)

Answer: D

52. The sugar which forms major component of nucleic acids is

A. ribose
B. galactose
C. mannose
D. maltose

Answer: A

53. Under aerobic condition pyruvate is converted by pyruvate dehydrogenase to

A. phosphoenol pyruvate
B. acetyl CoA
C. lactate
D. glyceraldehyde 3 phosphate

Answer: B
54. Which of the following is not a disaccharide?

A. Amylose
B. Cellobiose
C. Lactose
D. None of these

Answer: A

55. Hexokinase activity in glycolysis is inhibited by

A. glucose 6- phosphate
B. fructose 6-phosphate
C. fructose 1,6 biphosphate
D. phosphofructokinase

Answer: A

56. The ultimate source of energy that sustains living systems is

A. glucose
B. oxygen
C. sunlight
D. carbon dioxide

Answer: C

57. Citric acid accumulation would

A. stimulate phosphofructokinase activity

B. stimulate fructose 1,6 diphosphatase activity
C. inhibit phosphofructokinase activity
D. both (b) and (c)

Answer: D
58. Which of the following is not involved in the biosynthesis of DNA?

A. Energy from ATP

B. Mononucleotides
C. Carbonic anhydrase
D. Enzymes

Answer: C

59. Which of the following would be considered a part of metabolism?

A. Biosynthetic pathways that build DNA

B. Catabolic pathways that break down complex carbohydrates
C. The capture of light energy for use in making glucose
D. All of the above

Answer: D

60. Insulin

A. stimulates gluconeogenesis and glycolysis

B. stimulates gluconeogenesis and inhibits glycolysis
C. inhibits gluconeogenesis and glycolysis
D. inhibits gluconeogenesis and stimulates glycolysis

Answer: D

61. What is present in the stomach to prevent self-digestion?

A. Mucus
B. acid
C. Enzymes
D. hormones

Answer: A
 “CARBOHYDRATE METABOLISM”

62. Name the pathway for glucose synthesis by non-carbohydrate precursors?

A. Glycogenesis
B. Glycolysis
C. Gluconeogenesis
D. Glycogenolysis

Answer: C
Clarification: Synthesis of glucose from non-carbohydrate sources is carried out by
gluconeogenesis. It is the universal pathway, found in all plants, animals, and
microorganisms.

63. What is the site for gluconeogenesis?

A. Liver
B. Blood
C. Muscles
D. Brain

Answer: A
Clarification: Gluconeogenesis in animals takes place in the liver as well as some extent in
the kidney cortex. The kidney is capable of making glucose during the condition of starvation
and can make up to 50% of glucose.

64. Which of the following is not the precursor of gluconeogenesis?

A. Glycolytic products
B. Citric acid cycle intermediates
C. Glucogenic amino acid
D. Lysine or leucine

Answer: D
Clarification: Only leucine or lysine is the substrate which is not used for gluconeogenesis as
these amino acids produce only acetyl-CoA upon degradation. Animals cannot carry out
gluconeogenesis by two acetyl carbon of acetyl-CoA.

65. Name the enzyme which is responsible for the conversion of pyruvate to
phosphoenolpyruvate (PEP)?

A. Pyruvate carboxylase
B. Pyruvate carboxykinase
C. Glucose 6-phosphatase
D. Phosphofructokinase

Answer: B
Clarification: The conversion of pyruvate to PEP takes place in two stages, the first reaction
is catalyzed by pyruvate carboxylase which converts pyruvate to oxaloacetate and in second
reaction oxaloacetate is converted by pyruvate carboxykinase to PEP.

66. Gluconeogenesis is also carried out in muscle and brain.

A. True
B. False

Answer: B
Clarification: Gluconeogenesis cannot be carried out in muscle and brain as they do not have
glucose 6-phosphatase enzyme which is required to convert glucose 6-phosphate to glucose.
Glucose 6-phosphatase can only be established in the endoplasmic reticulum of kidney and
liver cells.

67. Which of the following are major sites for glycogen storage?

A. Adipose tissue
B. Bones
C. Muscle and liver
D. Kidney and liver

Answer: C
Clarification: Glycogen is stored in muscle and liver only. The amount of glycogen is high in
the liver but a larger amount of glycogen stored in the greater bunch of skeletal muscles. The
liver uses its glycogen for the synthesis of glucose for all of the body while muscles use its
glycogen for its own energy.

68. Which of the following is the precursor of glycogen?

A. Glycerol 3-phosphate
B. Malate
C. UDP-glucose
D. Leucine and lysine

Answer: C
Clarification: Glucose 1-phosphate and uridine triphosphate work together to activate UDP-
glucose which acts as a precursor of glycogen.

69. The priming function in glycogen synthesis is carried out by_________

A. Lysine
B. Arginine
C. Glycogenin
D. Glutamate

Answer: C
Clarification: Glycogen synthesis is carried out with the help of a primer by its priming
action. Glycogenin is a primer which adds glucosyl residue in the polypeptide chain that
already has more than four residues.

70. Name the enzyme which is used for branching of glycogen?

A. Branching enzyme
B. Hexokinase
C. Phosphoglucomutase
D. Glycogen synthase

Answer: A
Clarification: Branching enzyme is also known as amylo-1, 4 —–> 1, 6 transglycosylase
which adds a branch at four residues away from the existing branch. Enzymes in hexokinase,
phosphoglucomutase, and glycogen synthase are used in glycogen synthesis but not in
branching.

71. Which of the following hormone maintain blood glucose level by activation of
gluconeogenesis?

A. Nor-epinephrine
B. Glucagon
C. Insulin
D. Epinephrine

Answer: B
Clarification: Glucagon acts opposite to insulin, and is secreted by the α-cells of the
pancreatic islets. It maintains blood glucose level by the activation of glycogenolysis and
gluconeogenesis.

72. Name the hormone which is secreted in an emergency or in stress condition?

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

Answer: A
Clarification: Epinephrine is also known as emergency hormone and it is secreted in the
condition of stress and emergencies like injury, pain, fear, accident, and grief. It increases the
level of sugar in the blood by stimulating glycogenolysis.
 GLYCOLYSIS

73. Glycolytic pathway regulation involves

A. allosteric stimulation by ADP

B. allosteric inhibition by ATP
C. feedback, or product, inhibition by ATP
D. all of the above

Answer: D

74. 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.

Answer: A

75. 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

Answer: A

76. The released energy obtained by oxidation of glucose is stored as

A. a concentration gradient across a membrane

B. ADP
C. ATP
D. NAD+
Answer: C

77. 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

Answer: B

78. For every one molecule of sugar glucose which is oxidized __________ molecule of
pyruvic acid are produced.

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

Answer: B

79. In the glycogen synthase reaction, the precursor to glycogen is

A. glucose-6-P
B. UTP-glucose
C. UDP-glucose
D. glucose-1-P

Answer: C

80. The active form of glycogen phosphorylase is phosphorylated, while the

dephosphorylation of which active form occurs?

A. Glycogen synthase
B. Glycogen semisynthase
C. Glycogen hydrolase
D. Glycogen dehydrogenase
Answer: A

81. The enzymes of glycolysis in a eukaryotic cell are located in the

A. intermembrane space
B. plasma membrane
C. cytosol
D. mitochondrial matrix

Answer: C

82. When concentration of the reactants is higher than the equilibrium concentration
then

A. the gibbs free energy will be positive

B. the gibbs free energy will be negative
C. more products will be formed
D. both (b) and (c)

Answer: D

83. Which of the following is not true of glycolysis?

A. ADP is phosphorylated to ATP via substrate level phosphorylation

B. The pathway does not require oxygen
C. The pathway oxidizes two moles of NADH to NAD+ for each mole of glucose that enters
D. The pathway requires two moles of ATP to get started catabo-lizing each mole of glucose

Answer: C

84. 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

Answer: B

85. ATP is from which general category of molecules?

A. Polysaccharides
B. Proteins
C. Nucleotides
D. Amino acids

Answer: C

86. 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

Answer: A
 TCA CYCLE

87. How many molecules of ATPs are synthesized per NADH oxidation?

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

Answer: C

88. Why is the TCA cycle the central pathway of metabolism of the cell?

A. It occurs in the center of the cell

B. Its intermediates are commonly used by other metabolic reactions
C. All other metabolic pathways depend upon it
D. None of the above

Answer: B

89. In what form does the product of glycolysis enter the TCA cycle?

A. AcetylCoA
B. Pyruvate
C. NADH
D. Glucose

Answer: A

90. Malate-asparatate shuttle operates in

A. lungs and liver

B. heart and liver
C. pancreas and liver
D. none of these

Answer: B
91. Oxidation of a molecule involves

A. gain of electron
B. loss of electron
C. gain of proton
D. loss of proton

Answer: B

92. During cellular respiration, most of the ATP made, is generated by

A. oxidative phosphorylation
B. photophosphorylation
C. glycolysis
D. substrate-level phosphorylation

Answer: A

93. Important function of cholesterol is to

A. modulate fluidity
B. enhance blood circulation
C. prevent bile salts formation
D. None of these

Answer: B

94. To stop ATP synthesis which chemical is generally used?

A. DNSA
B. 2,4 dinitrophenol
C. DDT
D. None of the chemical can stop ATP synthesis

Answer: B

95. The enzymes of the TCA cycle in a eukaryotic cell are located in the
A. nucleus
B. mitochondria
C. plasma membrane
D. lysosomal bodies

Answer: B

96. Citric acid cycle occurs in

A. cytoplasm
B. mitochondria
C. endoplasmic reticulum
D. golgi bodies

Answer: B

97. 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

Answer: B

98. Standard redox potential for a substance is measured under standard condition and
is expressed as

A. mili-Ampere
B. Volt
C. without unit
D. Ohm

Answer: B
99. 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

Answer: C

100. A positive redox potential means substance has

A. lower affinity for electron

B. higher affinity for electron
C. lower affinity for proton
D. higher affinity for proton

Answer: B

101. The end product of glycolysis is pyruvate, which enters the citric acid cycle after
being converted to

A. acetic acid
B. acetyl-CoA
C. acetaldehyde
D. none of these

Answer: B

102. Energy that is released from glucose during respiration but not transferred to ATP
bonds can be detected as

A. CO2 B. AMP
C. ADP D. heat

Answer: D
103. Which of the following is involved in energy production?

A. Generation of proton gradients across membranes

B. Transport of electrons on organic molecules
C. Conversion of compounds with high energy to those of low energy
D. All of the above

Answer: D

104. Which of the following enzyme does not take part in the TCA cycle?

A. Citrate synthase
B. Iso-citrate dehydrogenase
C. Pyruvate dehydrogenase
D. Malate dehydrogenase

Answer: C

105. The first intermediate in TCA cycle is

A. succinate
B. fumerate
C. citrate
D. malate

Answer: C

106. Cholesterol can be synthesized de novo in

A. pancreas
B. intestine
C. liver
D. cell membrane

Answer: C
107. Which one of the following is not the intermediate of Kreb’s cycle?

A. Isocitrate
B. Succinate
C. Fumarate
D. Stearate

Answer: D

108. Which one is not the main protein in electron transport chain?

A. NADH dehydrogenase
B. Cytochrome bc1 complex
C. Cytochrome oxidase
D. Citrate synthease

Answer: D

109. How many ATPs are produced during citric acid cycle?

A. 10
B. 13
C. 12
D. 8

Answer: C

110. The FADH2 and NADH produced by the oxidation of one acetyl-CoA results in the
synthesis of about-

A. 3 ATPs
B. 6 ATPs
C. 11 ATPs
D. 15 ATPs

Answer: C
111. In eukaryotes, electron transport occurs in

A. membranes and mitochondria

B. endoplasmic reticulum
C. cytoplasm
D. all of the above

Answer: A

112. 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

Answer: A
 AMINO ACIDS AND PROTEINS
113. The general structure of all amino acids are same except for ___________
a) Lysine
b) Glycine
c) Proline
d) Alanine

Answer: c
Explanation: In general, all α-amino acid consists of an amino group, a hydrogen atom, and a
distinctive side chain, all bonded to α-carbon. Proline is the only amino acid which has a
cyclic distinctive side chain which differs from all other amino acids.

114. An amino acid is an amphoteric molecule.

a) True
b) False

Answer: a
Explanation: When an amino acid dissolved in water, it acts as acid or base and called as the
zwitterion or dipolar ion. Hence, an amino acid is an amphoteric molecule.

115. Which of these amino acids are not optically active?

a) Cysteine
b) Lysine
c) Arginine
d) Glycine

Answer: d
Explanation: When a carbon atom has four different constituents, it is said to be chiral. All
amino acids have chiral carbon except glycine and hence they are optically active.

116. Which of these are used to measure optical activity?

a) Polarimeter
b) Planometer
c) Psychrometer
d) Photometer

Answer: a
Explanation: Polarimeter is used to measure the rotation of polarized light while planometer
is used for area measurement and psychrometer measure humidity. Similarly, photometer
measures illuminance or irradiance.

117. A solution of L-alanine (4.0g/50 ml of 6 N HCl) has a rotation of +1.61° in a 2dm

polarimeter tube. Calculate the specific rotation of L-alanine in 6 N HCl.
a) +15.1°
b) +10.1°
c) +11.1°
d) +16.1°

Answer: b
Explanation: [α] = Α°/ l×C; +1.61/2×0.08
[α]= +10.1°.

118. Name the amino acid, which exists in two non-superimposable mirror images of
each other.
a) Epimer
b) Anomer
c) Enantiomer
d) Chiral carbon

Answer: c
Explanation: When an amino acid with a chiral carbon exists in two non-superimposable
mirror images of each other, it is called enantiomers. It can be easily identified by its
configuration.

119. Which of these are rare amino acid in a protein?

a) Leucine and serine
b) Lysine and glutamic acid
c) Tryptophan and methionine
d) Leucine and lysine

Answer: c
Explanation: Tryptophan and methionine are rare in protein as they have only one codon for
each while lysine, leucine, serine and glutamic acid have more than one codon for each
protein.

120. In which amino acid Imidazole group, an aromatic ring found?

a) Lysine
b) Arginine
c) Histidine
d) Glutamate

Answer: c
Explanation: Histidine contains imidazole group which can be uncharged or positively
charged, depending on its local environment. Lysine & arginine contains positively charged
R group while glutamate has negatively charged R group.

121. What is the maximum wavelength that Tryptophan and tyrosine absorb?
a) 280nm
b) 260nm
c) 257nm
d) 230nm

Answer: a
Explanation: Tryptophan, tyrosine, and phenylalanine are aromatic amino acids and absorbs
ultraviolet light (UV). Absorption at 280nm is used for quantification and detection of
purified proteins. The absorbance of proteins is dependent on number and position of
aromatic amino acid residues.

122. How is the secondary structure of a protein stabilized?

a) Van der wall forces
b) Hydrogen bonding
c) Covalent bond
d) Hydrophobic bond
Answer: b
Explanation: Hydrogen bonding can bring together two chains which are at distance in terms
of a sequence. Depending on hydrogen bonding, proteins have two structural conformations
α-helix and β-sheets.

123. How many amino acid residues are there in per turn of α-helix?
a) 3.6
b) 4.6
c) 3.0
d) 2.5

Answer: a
Explanation: Length of α-helix is usually 10-15 amino acid residue and there are 3.6 amino
acid residues per turn of the helix. A single turn of α-helix has 13 atoms due to this α-helix is
also referred as 3.613 helix.

124. Which of the following is true regarding the solubility of amino acids?

1. Mostly soluble in water and insoluble in organic solvents

2. They are only water-soluble
3. They are only soluble in organic solvents
4. Mostly soluble in organic solvents and insoluble in water

Answer: (a)

Explanation: In general, amino acids are soluble in water but insoluble in non-polar organic
solvents like hydrocarbons. This reflects the presence of zwitterions once more. The strong
ionic attractions between polar water molecules and the zwitterions in water replace the ionic
attractions between the ions in the solid amino acid.

125. Which of the following essential amino acids is not synthesized by the body?

1. Arginine
2. Glutamine
 3. Histidine
4. Proline

Answer: (c)

Explanation: The body does not produce essential amino acids. As a result, they must be
obtained through the consumption of food. Histidine, isoleucine, leucine, lysine,
phenylalanine, threonine, tryptophan, and valine are the nine essential amino acids.

126. From which of the following components amino acids are generally synthesized?

1. Fatty acids
2. 𝜶-ketoglutaric acid
3. Mineral Salts
4. Volatile acids

Answer: (b)

Explanation: Glutamate, glutamine, proline, and arginine are ketoglutarates. alpha -ketoacids
are used to make most amino acids, which are then transaminated from another amino acid,
usually glutamate. Aminotransferase is the enzyme involved in this process.

127. Amino acids with the non-polar aliphatic ‘R’ group are

1. Glycine, alanine, leucine

2. Serine, threonine, cysteine
3. Lysine, arginine, histidine
4. Phenylalanine, tyrosine, and tryptophan

Answer: (a)

Explanation: Amino acids contain aliphatic R groups that are non-polar or hydrophobic.
Glycine, alanine, valine, leucine, isoleucine, and proline are among the amino acids in this
category. The R groups in hydrocarbons are non-polar and hydrophobic.
128. Amino acids with aromatic side chains are

1. tryptophan, asparagine, tyrosine

2. tryptophan, threonine, tyrosine
3. phenylalanine, tryptophan, serine
4. phenylalanine, tryptophan, tyrosine

Answer: (d)

Explanation: When a side chain has an aromatic ring system, it is aromatic. The number of
electrons enclosed within the ring is the formal definition.

129. Which of the following amino acids yield Acetyl CoA during catabolism?

1. Ketogenic
2. Glucogenic
3. Essential
4. None of the above

Answer: (a)

Explanation: Amino acid catabolism begins at metabolic entry sites. Ketogenic amino acids
are those that create acetyl CoA. Leucine, lysine, phenylalanine, tyrosine, tryptophan, and
isoleucine are among them.

130. Which of the following is a true statement?

1. Tryptophan and tyrosine are significantly more polar than phenylalanine

2. Leucine is commonly used as an ingredient in the buffers of the SDS page
3. Aspartate is an essential amino acid
4. Lysine is a non-essential amino acid

Answer: (a)

Explanation: Because of the tyrosine hydroxyl group and the nitrogen of the tryptophan
indole ring, tryptophan and tyrosine are substantially more polar than phenylalanine.
131. Out of these, which one is the non-essential amino acid?

1. Lysine
2. Threonine
3. Serine
4. Histidine

Answer: (c)

Alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine,
proline, serine, and tyrosine are examples of non-essential amino acids.

131. Which of the following is an essential amino acid?

1. Cysteine
2. Asparagine
3. Glutamine
4. Phenylalanine

Answer: (d)

Explanation: The body does not produce essential amino acids. As a result, they must be
obtained through the consumption of food. Histidine, isoleucine, leucine, lysine,
phenylalanine, threonine, tryptophan, and valine are the nine essential amino acids.

132. The difference between amino acid and imino acid is

1. Bonding of carbonyl group with the amide group

2. Bonding of nitrogen in the amide group
3. Bonding of nitrogen in the carbonyl group
4. Presence of covalent bond between amide and carbonyl group

Answer: (b)

Explanation: The main distinction between an amino acid and an imino acid is that an amino
acid has both an amino and a carboxylic group in the same molecule, whereas an imino acid
contains both an imino and a carboxylic group.
133. Which of the following is an example of imino acid?

1. Alanine
2. Glycine
3. Proline
4. Serine

Answer: (c)

Explanation: Any molecule with both imine (>C=NH) and carboxyl (-C(=O)-OH) functional
groups is called an imino acid.

134. Which of the following amino acids is both glucogenic and ketogenic in nature?

1. Leucine
2. Lysine
3. Isoleucine
4. histidine

Answer: (c)

Explanation: As an energy source, isoleucine produces both glucose and ketone bodies.
During catabolism, pyruvate metabolites are generated in the case of glycogenic amino acids,
and acetoacetyl CoA is created in the case of ketogenic amino acids.

135. Which of the following is true in the case of an amino acid that yields acetoacetyl
CoA during the catabolism of its carbon skeleton?

1. It’s glycogenic in nature

2. It’s ketogenic in nature
3. It’s an essential amino acid
4. It can be either glucogenic or ketogenic in nature

Answer: (b)

Explanation: Pyruvate metabolites are generated during the catabolism of glycogenic amino
acids, while acetoacyl CoA is formed during the catabolism of ketogenic amino acids.
136. Among the 20 standard proteins which are coding amino acids, which of the
following occurs the least number of times in proteins?

1. Glycine
2. Alanine
3. Tryptophan
4. Methionine

Answer: (c)

137. Which of these is the first amino acid in a polypeptide chain?

1. Serine
2. Valine
3. Alanine
4. Methionine

Answer: (d)

Explanation: The codon AUG, often known as the start codon, specifies the amino acid
methionine. As a result, during protein synthesis, methionine is the first amino acid to dock in
the ribosome.

138. Which of the following are sulfur-containing amino acids?

1. Cysteine and methionine

2. Methionine and threonine
3. Cysteine and threonine
4. Cysteine and serine

Answer: (a)

Explanation: In practically all eukaryotic proteins, methionine is the starting amino acid; in
prokaryotes, N-formylmethionine performs the same function. Cysteine is important in
protein structure and folding pathways because of its capacity to create disulfide bonds.
139. Which of the following are positively charged basic amino acids?

1. Lysine and arginine

2. Lysine and asparagine
3. Glutamine and arginine
4. Lysine and glutamine

Answer: (a)

Explanation: Five of the twenty most often used amino acids have a charged side chain. At
pH=7, aspartic acid (Asp, D) and glutamic acid (Glu, E) (acidic side chains) are negatively
charged, and lysine (Lys, K), arginine (Arg, R), and histidine (His, H) are positively charged
(basic side chains).

140. Out of these, the acidic amino acids are-

1. Arginine and glutamate

2. Aspartate and asparagine
3. Aspartate and lysine
4. Aspartate and glutamate

Answer: (d)

Explanation: Aspartic acid, also known as aspartate (Asp), and glutamic acid, often known as
glutamate, are the two acids in question (Glu). Their side chains include carboxylic acid
groups with pKas low enough to lose protons, causing them to become negatively charged.

141. The 21st amino acid is

1. Hydroxy lysine
2. Hydroxyproline
3. Selenocysteine
4. citrulline

Answer: (c)
Explanation: The 21st amino acid in the genetic code, selenocysteine (Sec), is an uncommon
amino acid that is cotranslationally incorporated into proteins. UGA codons, which ordinarily
serve as stop signals, are used to encode Sec.

142. Out of the following, amino acids with hydroxyl groups are-

1. Serine and alanine

2. Alanine and Valine
3. Serine and threonine
4. Valine and Isoleucine

Answer: (c)

Explanation: Serine and threonine are two amino acids that contain aliphatic hydroxyl groups
(an oxygen atom connected to a hydrogen atom, denoted as OH). The total amino acid profile
of a food protein in comparison to a standard is a useful predictor of its potential nutritional
value, but it can be deceiving if one or more of the necessary amino acids are only partially
available.

143. Which of the following factors is not responsible for the denaturation of proteins?

(a) Heat

(b) Charge

(c) pH change

(d) Organic solvents

Answer: (b) Charge

144. Which of the following is responsible for specifying the 3D shape of a protein?

(a) The peptide bond

(b) The amino acid sequence

(c) Interaction with other polypeptides

(d) Interaction with molecular chaperons

Answer: (b) The amino acid sequence

145. ________is not a classified form of conjugated proteins.

(a) Lipoproteins

(b) Glycoproteins

(c) Metalloproteins

(d) Complete proteins

Answer: (d) Complete proteins

146. What is the average molecular weight of an amino acid residue in a protein?

(a) 120

(b) 110

(c) 130

(d) 140

Answer: (b) 110

147. Which of the following proteins was first sequenced by Frederick Sanger?

(a) Myosin

(b) Insulin

(c) Myoglobin

(d) Haemoglobin

Answer: (b) Insulin

148. Which of the following statements is true about proteins?

(a) Proteins are made up of amino acids.

(b) Proteins are essential for the development of skin, teeth and bones.

(c) Protein is the only nutrient that can build, repair and maintain body tissues.
(d) All of the above

Answer: (d) All of the above

149. How many amino acids make up a protein?

(a) 10

(b) 20

(c) 30

(d) 50

Answer: (b) 20

149. What is a bond between amino acids called?

(a) Ionic bond

(b) Acidic bond

(c) Peptide bond

(d) Hydrogen bond

Answer: (c) Peptide bond

150. Which of the following statements is true about proteins?

(a) Proteins are polymers of glucose

(b) Proteins are polymers of amino acids

(c) Proteins are polymers of peptide bonds

(d) Proteins are polymers of disulfide bridges

Answer: (b) Proteins are polymers of amino acids

151. Which of the following food products are high in protein content?

(a) Tofu and eggs

(b) Grains and legumes

(c) Milk and milk products

(d) All of the above

Answer: (d) All of the above

152. Which of the following statements is true about the complete proteins?

(a) High-protein foods that stabilize body weight

(b) Food that has a balanced amount of fat and protein

(c) Foods that provide all the amino acids that the body needs

(d) All of the above

Answer: (d) All of the above

153. Which of the following techniques is used to determine the protein structures?

(a) X-ray crystallography

(b) Kryptonics X-ray vision

(c) Magnetic resonance imaging (MRI)

(d) None of the above

Answer: (a) X-ray crystallography

154. Which of the following disorders is caused by the deficiency of proteins?

(a) Weight loss

(b) Muscle fatigue

(c) Loss in muscle strength

(d) All of the above

Answer: (d) All of the above

155. Which of the following cell organelles is involved in the process of protein
synthesis?

(a) Vesicles

(b) Ribosomes

(c) Synchrotrons

(d) Mitochondria

Answer: (b) Ribosomes

156. Which of the following is not the function of proteins?

(a) Helps in digesting food

(b) Carries genetic information

(c) Fights against the invading pathogens

(d) Helps in transporting oxygen in the blood

Answer: (b) Carries genetic information

157. The 3-D structure of proteins can be determined by________.

(a) Spectroscopy

(b) X-ray crystallography

(c) Nuclear magnetic resonance

(d) Both (b) and (c)

Answer: (d) Both (b) and (c)

158. Which of the following is true about enzymes?

(a) Proteins
(b) Nucleic acids

(c) Carbohydrates

(d) DNA molecule

Answer: (a) Proteins

159. Which of the following statements is true about the (primary ) 1° structure of
proteins?

(a) The helical structure of the protein

(b) Subunit structure of the protein

(c) Three-dimensional structure of the protein

(d) The sequence of amino acids joined by a peptide bond

Answer: (d) The sequence of amino acids joined by a peptide bond

160. Which of the following diseases is caused by protein deficiency?

(a) Anaemia

(b) Kwashiorkor

(c) Hypothyroidism

(d) All of the above

Answer: (b) Kwashiorkor

161. The process of protein synthesis takes place in which of the following cell
organelles?

(a) Nucleus

(b) Vacuoles
(c) Cytoplasm

(d) Mitochondria

Answer: (c) Cytoplasm

 Amino Acids, DNA and RNA
162. In double helix of DNA, the two DNA strands show which type of characteristics?
a) coiled around a common axis
b) coiled around each other
c) coiled differently
d) coiled over protein sheath

Answer: a
Explanation: The DNA molecule consists of two long, parallel chains which are joined
together by short crossbars at regular intervals. The two chains are spirally coiled around a
common axis in a regular manner to form a right handed double helix.

163. A nucleotide is formed of which of the following units?

a) nitrogen base and phosphate
b) nitrogen base, sugar and phosphate
c) nitrogen base and sugar
d) sugar and phosphate

Answer: b
Explanation: Nucleotide is an organic compound consisting of a nitrogen-containing purine
or pyrimidine base linked to a sugar (ribose or deoxyribose) and a phosphate group.

164. Which of the following nitrogenous base is not present in RNA?

a) adenine
b) thymine
c) cytosine
d) guanine

Answer: a
Explanation: Though both RNA and DNA contain the nitrogenous bases adenine, guanine
and cytosine, RNA contains the nitrogenous base uracil instead of thymine. Uracil pairs with
adenine in RNA, just as thymine pairs with adenine in DNA.
165. To which of the following does thymine form hydrogen bonds in DNA?
a) adenine
b) thymine
c) cytosine
d) guanine

Answer: a
Explanation: In molecular biology, two nucleotides on opposite complementary DNA strands
that are connected via hydrogen bonds are called a base. In the Watson-Crick DNA base
pairing, Adenine (A) forms a base pair with Thymine (T) and Guanine (G) forms a base pair
with Cytosine (C).

166. What term is used to describe the process by which DNA is copied to produce two
daughter DNA molecules?
a) reproduction
b) replication
c) translation
d) transcription

Answer: b
Explanation: Replication is the copying of DNA into two daughter DNA molecules.
Translation is the process by which the genetic code for a specific protein (carried in
messenger RNA) is used for the synthesis of a new protein.

167. What term is used to describe the process by which a segment of DNA is copied to
produce a molecule of messenger RNA?
a) reproduction
b) replication
c) translation
d) transcription

Answer: d
Explanation: Transcription is the term used to describe how the genetic code relevant for the
synthesis of one protein (a gene) is copied from DNA to form messenger RNA.
168. What amino acid is coded by the triplet of bases UAU?
a) phenylalanine
b) serine
c) tyrosine
d) cysteine

Answer: c
Explanation: The triplet code for phenylalanine can be UUU or UUC. For serine it can be
UCU, UCC, AGU or AGC. For tyrosine, it is UAU or UAC. For cysteine it can be UGU or
UGC.

169. To which of the following does guanine form hydrogen bonds in DNA?
a) adenine
b) thymine
c) cytosine
d) guanine

Answer: c
Explanation: In molecular biology, two nucleotides on opposite complementary DNA strands
that are connected via hydrogen bonds are called a base. In the Watson-Crick DNA base
pairing, Adenine (A) forms a base pair with Thymine (T) and Guanine (G) forms a base pair
with Cytosine (C).

170. A nucleoside is formed of which of the following units?

a) nitrogen base and phosphate
b) nitrogen base, sugar and phosphate
c) nitrogen base and sugar
d) sugar and phosphate

Answer: c
Explanation: A nucleoside consists simply of a nucleobase (also termed a nitrogenous base)
and a five-carbon sugar (either ribose or deoxyribose).
171. DNA is composed of repeating units of ___________
a) ribonucleosides
b) deoxyribonucleosides
c) ribonucleotides
d) deoxyribonucleotides

Answer: d
Explanation: It is a long, double” chain of deoxyribonucleotide, or deoxyribotide, units. The
two deoxyribonucleotide chains are twisted around a common axis to form a right-handed
double helix (spiral) that encloses a cylindrical space in it. Each deoxyribonucleotide unit, in
turn, consists of three different molecules: phosphate molecule, a 5-carbon deoxyribose sugar
and a nitrogenous base.

172. Glycine and proline are the most abundant amino acids in which of the following
structure?
a) Hemoglobin
b) Myoglobin
c) Insulin
d) Collagen

Answer: d
Explanation: Glycine and proline are the most abundant amino acids in collagen. The most
common motifs in the amino acid sequence of collagen are glycine-proline-X and glycine-X-
hydroxyproline, where X is any amino acid other than glycine, proline or hydroxyproline.

173. Which of the following statements about amino acids is correct?

a) Amino acids are uncharged at neutral pH
b) Amino acids are classified according to the structures and properties of their side chains
c) Amino acids in proteins are mainly in the D-configuration
d) Twenty four amino acids are commonly used in protein synthesis

Answer: b
Explanation: Amino acids are usually classified by the properties of their side chain into four
groups. The side chain can make an amino acid a weak acid or a weak base, and a hydrophile
if the side chain is polar or a hydrophobe if it is nonpolar.

174. Which of the following amino acids is mostly likely to disrupt an alpha helix?
a) Proline
b) Leucine
c) Glycine
d) Valine

Answer: a
Explanation: Certain amino acids with simple side chains, such as alanine, are very favorable
for formation of alpha helices, whereas cyclic amino acids like proline tend to disrupt alpha
helices.

175. Which amino acid can form disulphide bonds?

a) Proline
b) Leucine
c) Cysteine
d) Valine

Answer: c
Explanation: Cysteine aminoacid can form disulphide bond(bond which joins two atoms of
sulphur atom) because this is the only amino acid with a sulphydryl group in its side chain is
cysteine.
176. Which of the following amino acid is a limiting amino acid in pulses?
a) Leucine
b) Lysine
c) Methionine
d) Glutamine

Answer: c
Explanation: Amino acids that are present in low proportion limit the functioning of the
proteins, and are so called limiting amino acids of those particular proteins. Generally
proteins in pulses like beans are limited in methionine.
177. Which of the characteristics below apply to amino acid Glycine?
a) Optically inactive
b) Hydrophilic, basic and charged
c) Hydrophobic
d) Hydrophilic, acidic and charged

Answer: a
Explanation: The entire class of amino acids has a common backbone of an organic
carboxylic acid group and an amino group attached to a saturated carbon atom. The simplest
member of this group is glycine, where the saturated carbon atom is unsubstituted, rendering
it optically inactive.

178. Which of the following bonds are broken during DNA replication?
A hydrogen bonds between bases
B phosphodiester bonds
C covalent bonds between bases
D ionic bonds between bases and phosphate groups
Your answer A

179. Which base is not found in RNA?

A adenine
B cytosine
C thymine
D uracil
Your answer
C

180. How many base pairs are there in one full turn of the DNA double helix?
A 4
B 10
C 16
D 64
Your answer
B
181. Analysis of a sample of DNA found that 20% of the bases were adenine.
What percentage of the bases would be pyrimidines?
A 20%
B 30%
C 60%
D 50%
Your answer
D
182. Which technique was used to determine the double-helical structure of DNA?
A electrophoresis
B chromatography
C centrifugation
D X-ray crystallography
Your answer D

183. Analysis of a molecule of DNA found it to contain 200 adenine bases, 20% of the total
number of bases in the strand.
How many phosphate groups did it contain?
A 200
B 400
C 800
D 1000
Your answer D

184. Which of the following options, A – D, are the pyrimidine bases found in DNA?
A uracil and thymine
B thymine and cytosine
C adenine and thymine
D cytosine and uracil
Your answer B

185. If 30% of the bases in a DNA molecule are adenine, what percentage of the bases are
guanine?
A 20%
 B 30%
C 35%
D 70%
Your answer A

186. Thymine comprised 36% of the nitrogen bases present in a sample of double stranded
DNA.
What was the percentage of guanine in the sample?
A 14%
B 28%
C 36%
D 64%
Your answer A

187. Three of the bases found in nucleic acids are pyrimidines and two are purines. Which of
the following is correct?
Pyrimidines Purines
A adenine and thymine cytosine and guanine
B adenine and cytosine thymine and guanine
C uracil and thymine adenine and guanine
D cytosine and uracil thymine and cytosine

Your answer C

188. The research of Erwin Chargaff was essential in the discovery of the structure of DNA
by Crick and Watson. Chargaff analysed the base composition of DNA from a wide range of
organisms.
He reported his findings using the initial letter of each base to stand for the number of that
base found in an organism’s genome.
A=number of adenine bases G=number of guanine bases

C =number of cytosine bases T=number of thymine bases

Which of these relationships did he find within the genome of each organism he studied?
 A A=G C=T

B A+T = C+G

C A+G = T+C

D A=C G=T
C
Your answer

189. A piece of DNA was analysed and 15% of its nucleotides were adenine.
What percentage would be uracil?

A 0%

B 15%

C 30%

D 35%
A
Your answer

190. Foot and mouth disease virus (FMDV) is the pathogen that causes foot and mouth
disease in livestock.
An analysis of the genetic material of the ‘O’ strain of FMDV showed that it contains
1996 adenine bases, 2131 guanine bases, 1642 uracil bases and 2365 cytosine bases.

Which one of the following describes the genetic material of the virus?

A single-stranded DNA

B single-stranded RNA

C double-stranded DNA

D double-stranded RNA
B
Your answer
191. How many different trinucleotides can be made using the DNA nucleotides?

A 4

B 20

C 16

D 64
D
Your answer

192. How many polynucleotide strands are found in a tRNA molecule?

A 1

B 2

C 3

D 4
A
Your answer

Questions 193 and 194 refer to the following diagram of a section of a DNA molecule.
Y

A
X

G
193. Which are the two components of part X?

A ribose and phosphate

B guanine and phosphate

C deoxyribose and thymine

D deoxyribose and phosphate

D
Your answer

A
X

194. What type of bond is Y?

A covalent

B ester

C phosphodiester

D hydrogen
D
Your answer
 NUCLEIC ACIDS
195. Which of the following bonds are broken during DNA replication?

A hydrogen bonds between bases

B phosphodiester bonds

C covalent bonds between bases

D ionic bonds between bases and phosphate groups

Your answer A

196. Which base is not found in RNA?

A adenine

B cytosine

C thymine

D uracil
C
Your answer

197. How many base pairs are there in one full turn of the DNA double helix?

A 4

B 10

C 16

D 64
B
Your answer

198. Analysis of a sample of DNA found that 20% of the bases were adenine.
What percentage of the bases would be pyrimidines?

A 20%
 B 30%

C 60%

D 50%
C
Your answer

199. Which technique was used to determine the double-helical structure of DNA?

A electrophoresis

B chromatography

C centrifugation

D X-ray crystallography
D
Your answer

200. Analysis of a molecule of DNA found it to contain 200 adenine bases, 20% of the total
number of bases in the strand.
How many phosphate groups did it contain?

A 200

B 400

C 800

D 1000
D
Your answer

201. Which of the following options, are the pyrimidine bases found in DNA?

A uracil and thymine

B thymine and cytosine

C adenine and thymine

D cytosine and uracil

B
 Your answer

202. If 30% of the bases in a DNA molecule are adenine, what percentage of the bases are
guanine?

A 20%

B 30%

C 35%

D 70%
A
Your answer

203. Thymine comprised 36% of the nitrogen bases present in a sample of double stranded
DNA. What was the percentage of guanine in the sample?

A 14%

B 28%

C 36%

D 64%
A
Your answer

204. Two of the bases found in nucleic acids are pyrimidines and two are purines.
Which of the following is correct?

Pyrimidines Purines

A adenine and thymine cytosine and guanine

B adenine and cytosine thymine and guanine

C uracil and thymine adenine and guanine

 D cytosine and uracil thymine and cytosine

A
Your answer

205. The research of Erwin Chargaff was essential in the discovery of the structure of DNA
by Crick and Watson. Chargaff analysed the base composition of DNA from a wide range of
organisms.

He reported his findings using the initial letter of each base to stand for the number of that
base found in an organism’s genome.

A=number of adenine bases G=number of guanine bases

C =number of cytosine bases T=number of thymine bases

Which of these relationships did he find within the genome of each organism he studied?

A A=G C=T

B A+T = C+G

C A+G = T+C

D A=C G=T
B
Your answer

206. A piece of DNA was analysed and 15% of its nucleotides were adenine.

What percentage would be uracil?

A 0%

B 15%

C 30%
 D 35%
B
Your answer

Questions 207 and 208 refer to the diagram of part of a DNA molecule.

Q
Guanine R

Adenine

207. What is the part labelled Q?

A adenine

B cytosine

C thymine

D uracil
B
Your answer
208. Which parts, Q, R or S, contain carbon?

A Q and R

B Q and S

C R and S

D Q, R and S
A
Your answer
 DNA STRUCTURE

209. The accepted hypothesis for DNA replication is

A. conservative theory
B. dispersive theory
C. semi-conservative theory
D. evolutionary theory

Answer: C

210. 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

Answer: B

211. Telomeres are usually rich in which nucleotide?

A. Adenine
B. Guanine
C. Thymine
D. Cytosine

Answer: B

212. Which is the largest among the followings?

A. Nucleotide
B. Nitrogenous base
C. Phosphate
D. Carbon
Answer: A

213. 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 H4
D. two types of histone as H1 and H4

Answer: B

214. Taylor, Woods and Hughes labeled Vicia DNA by allowing new DNA synthesis in
the presence of radioactive thymine. After DNA replication (S phase of the cell cycle), it
was observed that

A. only one chromatid of a chromosome was labeled

B. both chromatids of a chromosome were labeled
C. both (a) and (b)
D. neither chromatid was labeled

Answer: B

215. 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. none of the above

Answer: B

216. 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
Answer: B

217. Messelsen and Stahl model of replication was called

A. conservative replication
B. semi-conservative replication
C. dispersive replication
D. Cri du Chat

Answer: B

218. The most common liquid volumes in molecular biology are measured in

A. ml
B. µl
C. nl
D. 1

Answer: B

219. DNA replication takes place in which direction?

A. 3′ to 5′
B. 5 ‘to 3’
C. Randomly
D. Vary from organism to organism

Answer: B

220. DNA gyrase in E. coli

A. adds positive supercoils to chromosomal DNA

B. can be inhibited with antibiotics
C. is required only at the oriC site
D. performs the same function as helicase in eukaryotes

Answer: B
221. In DNA, there are

A. 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

Answer: B

222. In DNA, guanine pairs with

A. Adenine B. Cytosine
C. Thymine D. Uracil

Answer: B

223. Which of the following is incorrect?

A. In DNA double helix, two strands of the DNA are bound with each other with the bases
B. Adenine always pairs with thymine
C. Guanine always pairs with the cytosine
D. None of the above

Answer: D

224. What is the only common methylation in the DNA of eukaryotes?

A. Adenosine in GpA dinucleotides

B. Guanosine in ApGpA trinucleotides
C. Cytosine in CpG dinucleotides
D. None of the above

Answer: C

225. DNAs when charged, migrate in a gel towards the

A. positive pole
B. negative pole
C. will not migrate
D. none of these

Answer: A

226. What is the approximate size (in kb) of the E. coli genome?

A. 3000 kilobase
B. 4500 kilobase
C. 5500 kilobase
D. 6500 kilobase

Answer: B

227. 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

Answer: B

228. 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

Answer: D
 DNA REPLICATION

229. 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

Answer: A

230. A cesium chloride will separate DNA molecules by

A. absorption
B. resorption
C. density
D. adhesion

Answer: C

231. 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

Answer: C

232. Which of the following enzyme adds complementary bases during replication?

A. Helicase
B. Synthesase
C. Replicase
D. Polymerase

Answer: D
233. Which DNA polymerase removes RNA primers in DNA synthesis?

A. Polymerase I
B. Polymerase II
C. Polymerase III
D. none of these

Answer: A

234. Enzymes, responsible for unraveling short segments of DNA is

A. DNA polymerase
B. helicase
C. DNA ligase
D. primase

Answer: B

235. Enzyme, responsible for proofreading base pairing is

A. DNA polymerase
B. Telomerase
C. Primase
D. DNA ligase

Answer: A

236. Which of the following would not contain DNA?

A. Yeast
B. Bacteria
C. Glass crystals
D. Mold

Answer: C
237. The nucleosome consists of histone

A. octamer and 146 bp of DNA

B. tetramer and 146 bp of DNA
C. hexamer and 146 bp of DNA
D. none of the above

Answer: A

238. 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

Answer: B

239. Proteins involved in opening a replication bubble are

A. DNA helicases
B. single stranded binding proteins
C. ligase
D. DNA topoisomerase

Answer: D

240. What is the main damaging effect of UV radiation on DNA?

A. Depurination
B. Formation of thymine dimers
C. Single strand break
D. Dehydration

Answer: B
241. The higher order structure of DNA shows symmetry, whereas the higher order
structures of most proteins do not. Why isn’t protein shape more regular like DNA?

A. DNA has one main function in cells whereas proteins have many.
B. The many different amino acid R groups on proteins confer many different shapes.
C. Some S amino acids cause proteins to bend; others cause protein to flatten.
D. All of the above

Answer: D

242. DNA helicase is used to

A. unwind the double helix

B. interact the double helix closely
C. break a phosphodiester bond in DNA strand
D. none of the above

Answer: A

243. Klenow fragment without free nucleotides exhibits

A. exonuclease activity
B. endonuclease activity
C. nickase activity
D. no activity

Answer: A

244. 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

Answer: A
245. 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

Answer: A

246. Okazaki fragments occur during

A. transformation
B. replication
C. polymerase reaction
D. synthesis

Answer: B

247. DNA can be sequenced by the

A. chemical method
B. chain termination procedure
C. both (a) and (b)
D. physical method

Answer: C

248. Which histone(s) are associated with the linker DNA of a nucleosome?

A. Histone H1
B. Histones H2A and H2B
C. Histone H3
D. Histone H4

Answer: A
 TRANSCRIPTION

249. Which of the following enzyme is used for synthesis of RNA under the direction of
DNA?

A. RNA polymerase
B. DNA ligase
C. DNA polymerase
D. RNA ligase

Answer: A

250. What is the usual sequence of a Pribnow box?

A. AUAUA
B. TATAAT
C. UUUUU
D. TTGACA

Answer: B

251. Which of the following component of RNA polymerase facilitates the recognition of
promoter sequences?

A. a subunit
B. b subunit
C. s subunit
D. c subunit

Answer: C

252. Which of the following statement defines a replicon?

A. A DNA molecule that encodes pili for conjugation

B. A DNA molecule that is able to replicate and be maintained
C. A DNA template which is used in transcription
D. The enzyme responsible for transposition
Answer: B

253. Which eukaryotic RNA polymerase makes tRNA’s?

A. RNA polymerase 1
B. RNA polymerase 2
C. RNA polymerase 3
D. Any of these

Answer: C

254. The location of first hexameric sequence typically found in pro-karyotic promoters
is

A. at the transcription start site

B. approximately 35 bases upstream of the transcription start site
C. approximately 10 bases upstream of the transcription start site
D. approximately 25 bases upstream of the transcription start site

Answer: B

255. Which of the following is a product of transcription?

A. mRNA
B. tRNA
C. rRNA
D. all of these

Answer: D

256. The sigma factor

A. is responsible for recognizing the termination sequence

B. provides the catalytic function of cleaving off pyrophosphates during mRNA synthesis
C. recognizes the promotor
D. accomplishes DNA restriction
Answer: C

257. The synthesis of mRNA based on a DNA template is called

A. DNA replication
B. transcription
C. translation
D. DNA restriction

Answer: B

258. Recognition/binding site of RNA polymerase is called

A. receptor
B. promoter
C. facilitator
D. terminator

Answer: B

259. Which of the following enzyme(s) is/are required for lactose fermentation?

A. Transacetylase
B. ß-galactosidase
C. Galactoside permease
D. All of these

Answer: D

260. Which of these catalyzes the synthesis of RNA from a DNA template?

A. DNA gyrase
B. DNA ligase
C. DNA polymerase
D. RNA polymerase

Answer: D
261. A level of regulation, demonstrated by the termination of transcription if
tryptophan is abundant, by the tryptophan operon in E.coli cells is called

A. activation
B. attenuation
C. corepression
D. desiccation

Answer: B

262. An mRNA transcript of a gene contains

A. a start codon
B. a stop codon
C. a terminator
D. all of these

Answer: D

263. The process of formation of RNA is known as___________

A. Replication
B. DNA repair
C. Translation
D. Transcription
Answer: D
Clarification: Transcription is a process of formation of the transcript or RNA with the help
of RNA polymerase.

264. Like replication, transcription also occurs bidirectionally.

A. True
B. False
Answer: B
Clarification: Transcription occurs unidirectionally and synthesized RNA chain from 5’ to 3’
direction.
265. Mark the statement which is INCORRECT about the transcription unit?
A. It is a transcribed segment of DNA
B. Eukaryotes have monocistronic transcription unit
C. Prokaryotes also have a monocistronic transcription unit
D. Immediate product of transcription is primary transcript
Answer: C
Clarification: Transcription unit is the transcribed segment of DNA. If the transcription unit
carries information of one gene, it is called monocistronic while a set of adjacent genes when
transcribed as a unit called polycistronic.

266. Name the site where upstream sequences located?

A. Prior to start point
B. After the startpoint
C. Right border of DNA
D. In the middle of DNA
Answer: A
Clarification: Start point is the first base pair from which transcription starts. Upstream
sequences are located prior to the start point while sequences after the start point are called
downstream of it.

267. Which of the following is TRUE for the RNA polymerase activity?
A. DNA dependent DNA synthesis
B. Direct repair
C. DNA dependent RNA synthesis
D. RNA dependent RNA synthesis
Answer: C
Clarification: RNA polymerase is also known as DNA dependent RNA polymerase enzyme
and it involves a synthesis of RNA from DNA.

268. Who discovered RNA polymerase?

A. Samuel B. Weiss
B. Nirenberg
C. Watson and Crick
D. Darwin
Answer: A
Clarification: Samuel B. Weiss and Jerard Hurwitz in 1960 discovered RNA polymerase.
RNA polymerase is also known as DNA dependent.

269. Which of the following ensure stable binding of RNA polymerase at the promoter
site?
A. DNA photolyase
B. Sigma factor
C. DNA glycosylase
D. RecA
Answer: B
Clarification: Sigma factor decreases the binding of the core enzyme to non-specific DNA
sequences and increases binding to the promoter.

270. What is the work of the sigma factor in transcription?

A. Helicase action
B. Transcription initiation
C. Transcription elongation
D. Transcription termination
Answer: B
Clarification: Sigma factor is only involved in transcription initiation not in elongation. The
sigma factor is released from the core enzyme when the transcript reaches more than 8-9
nucleotide.

271. Name the sigma factor which is used for promoter recognition?
A. Sigma 32
B. Sigma 70
C. Sigma 60
D. Sigma 40
Answer: B
Clarification: There are 7 different types of sigma factors have been reported in E. coli but
the most common is sigma 70.

272. Which of the following is used to describe the time taken by RNA polymerase to
leave the promoter?
A. Promoter clearance time
B. Abortive initiation
C. Elongation factor
D. Mean time
Answer: A
Clarification: Promoter clearance time is the time taken by RNA polymerase core enzyme to
leave the promoter. More the efficient promoter sequences, lesser would be the promoter
clearance time.

273. How many base pairs of DNA is transcribed by RNA polymerase in one go?
A. 5-6
B. 3
C. 4
D. 7-8
Answer: D
Clarification: The RNA polymerase core enzyme moves along the template strand at uneven
base i.e, moves over 7-8 base pairs in one go.

274. Which of the following transcription termination technique has RNA dependent
ATPase activity?
A. Intercalating agents
B. Rho dependent
C. Rho independent
D. Rifampcin
Answer: B
Clarification: The rho factor functions as a Hexamer and has an RNA binding site and is
responsible for the termination of transcription. It has RNA dependent ATPase activity.

275. Name the one intrinsic terminator of transcription.

A. Intercalating agents
B. Rho independent
C. Rho dependent
D. Acridine orange
Answer: B
Clarification: Rho independent transcription termination is also known as intrinsic
terminators and about 50% of E. coli genes have these types of terminators.
276. Mark the one, which is NOT the transcription inhibitor in eukaryotes.
A. Rifampicin
B. Acridine dye
C. Actinomycin D
D. Rho factor
Answer: D
Clarification: Rifampicin inhibits beta subunit of RNA polymerase II while acridine orange
and actinomycin D is used to block elongation.
 TRANSCRIPTION AND TRANSLATION OF GENETIC INFORMATION

278. Translation takes place before transcription.

A. True
B. False
Answer: B
Clarification: According to the central dogma of molecular genetics, the first step is DNA
replication, the second is a transcription and the last step is translation.

279. Which of the following bacteria can synthesize all of the amino acids required for
protein synthesis?
A. E.coli
B. Lactobacillus bravis
C. Saccharomyces cerevisiae
D. Bacillus subtilis
Answer: A
Clarification: Microorganisms differ widely in their ability to synthesize amino acids like
E.coli can synthesize all of the amino acids required for protein synthesis, whereas lactic acid
bacteria cannot.

280. RNAase is a single polypeptide chain of __________ amino acid residues.

A. 2
B. 350
C. 4
D. 124
Answer: D
Clarification: RNAase is a single polypeptide chain of 124 amino acid residues; it is folded,
bent and twisted into a globular shape in its active form.

281. Protein synthesis in bacteria takes place on which of the following organelles?
A. Endoplasmic Reticulum
B. Golgi body
C. Ribosomes
D. Mitochondria
Answer: C
Clarification: Protein synthesis in bacteria takes place on the ribosomes, which are larger
RNA-protein particles in the cytoplasm of the bacterial cell.

282. Which of the following RNA constitutes 90 percent of the total cellular RNA?
A. rRNA
B. tRNA
C. mRNA
D. hnRNA
Answer: A
Clarification: Ribosomal RNA (rRNA. constitutes about 90 percent of the total cellular RNA
and this is important from all other types of RNA.

283. The synthesis of polynucleotide chain of mRNA is catalyzed by the enzyme

_____________
A. RNA helicase
B. RNA polymerase
C. DNA polymerase
D. DNA helicase
Answer: B
Clarification: The synthesis of polynucleotide chain of mRNA is catalyzed by the enzyme
RNA polymerase. The process in which a single-stranded mRNA is synthesized
complementary to one DNA strand is called transcription.

284. Which of the following is responsible for the initiation of RNA polymerase activity?
A. initiation site
B. promoter region
C. sigma factor
D. rho factor
Answer: C
Clarification: In bacteria, the initiation of RNA polymerase activity at the initiation site is due
to an initiation factor called the sigma factor, which is a component of the enzyme.

285. Rho factor is a dimeric protein factor.

A. True
B. False
Answer: B
Clarification: Rho factor is a tetrameric protein factor that binds to RNA polymerase and
promotes its termination. When transcription has been completed, rho dissociates from the
RNA polymerase-DNA complex.

286. The following code codes for which of the amino acid respectively?
AUG and GUG
A. Phenylalanine, tyrosine
B. Methionine, valine
C. Methionine, alanine
D. Lysine, valine
Answer: B
Clarification: Three base triplets form a codon that codes for an amino acid. Thus AUG codes
for methionine and GUG codes for Valine. AUG and GUG are both initiating codons for
translation.

287. Which of the following are non-sense codons?

A. AUG
B. GUG
C. UAA
D. UCU
Answer: C
Clarification: UAA, UAG and UGA are polypeptide-chain-terminating codons and are called
non-sense codons.
 “TRANSCRIPTION IN EUKARYOTES: TRANSCRIPTION FACTORS”

288. Which of this is a cis binding element?

A. TAF
B. TBP
C. TFIIF
D. TFIIH
Answer: B
Clarification: TBP or TATA binding protein is the part of TFIID complex that recognizes and
binds the TATA consensus sequence in the promoter (cis element) of eukaryotic genes. The
remaining options are also related to eukaryotic transcription but they have protein-protein
interactions.

289. You wanted to study the assembly of preinitiation complex in eukaryotes. This is
by the means of protein-protein interaction. Which of these methods you can’t
absolutely put in use there?
A. Footprinting
B. Crystal structure
C. EMSA
D. Primer extension
Answer: D
Clarification: While primer extension method can be used to locate the 5’ end of the RNA
this doesn’t do any help in studying the assembly of pre initiation complex- basically as that’s
upstream to even transcription start site. The remaining methods are however very useful.

290. For performing EMSA what type of gel should be used?

A. Native
B. Denaturing SDS-PAGE
C. Non-denaturing SDS PAGE
D. Zymography
Answer: C
Clarification: A denaturing SDS PAGE would break the interactions between the factors
which is being studied. Thus, a non-denaturing SDS PAGE is used. A native page on the
other hand would be less clear while zymography is unrelated.
291. While performing EMSA, in which situation will you see the band highest?
A. You add TFIID, TFIIA and polymerase
B. You add TFIID, TFIIB, TFIIF and polymerase
C. You add TFIID, TFIIA, TFIIF and polymerase
D. You add TFIIA, TFIIB, TFIIF and polymerase
Answer: B
Clarification: TFIID is absolutely necessary for any nucleation to take place at all. The
complex formed by this composition is almost functional as TFIIA is not playing that
important role. However, TFIIB and TFIID absence hugely effects the formation of pre-IC.

292. Which of these is not true for TFIIH?

A. It is a helicase
B. On initiation the RNA pol starts transcribing leaving TFIIH at pre-IC
C. It has kinase activity
D. It is needed in Double Strand Break (DSB. repair
Answer: B
Clarification: TFIIH is necessary for phosphorylating RNA pol and triggering its initiation. It
moves on with the RNA pol after initiation starts. It also acts as a helicase which is put to use
during DSB repair.

293. A mediator helps to connect ___________

A. Enhancer to DPE
B. Silencer to Enhancer
C. Enhancer to TAF
D. Insulator to silencer
Answer: C
Clarification: As enhancer elements work from a distance the connecting DNA is often
looped and the enhancer connects to the RNA pol bound TAF through a mediator. A silencer
may connect to TAF in a similar way.

294. Which factor stimulated phosphorylation of CTD of RNA polymerase II?

A. TFIIA
B. TFIIF
C. TFIIH
D. TFIIE
Answer: D
Clarification: While TFIIH is actually performing the kinase action, TFIIE stimulates TFIIH
to phosphorylate the CTD. TFIIA and TFIIF play no role in phosphorylation.

295. The absence of which factor will prevent TFIIH and TFIIE recruitment?
A. F
B. D
C. B
D. A
Answer: A
Clarification: RNA polymerase bound TFIIF is necessary for recruiting TFIIH and TFIIE,
two important transcription factors that trigger the initiation finally.

296. Which of this is untrue about TBP?

A. It is a part of TFIID
B. It makes a kink in the DNA
C. It is orientation independent
D. It is sequence independent
Answer: D
Clarification: TBP specifically recognizes and binds to TATA consensus sequence which
makes it sequence dependent. Its correct orientation is however determined by other factors
like TFIIA and TFIIB. It makes an 80 kink in the DNA and is a part of TFIID.

297. While in vitro transcription your RNA pol is stalled at a position due to
mistreatment. Which factor could you act to help the RNA pol overcome the stalled
stage?
A. TFIID
B. TFIIF
C. TFIIS
D. TFIIH
Answer: C
Clarification: TFIIS is the transcription factor that helps to overcome the transcriptional
stalling of RNA polymerases and also to help the polymerase to backtrack.
 PROTEIN SYNTHESIS

298. On the ribosome, mRNA binds

A. between the subunits

B. to the large subunit
C. to the small subunit
D. none of these

Answer: C

299. Type I proteins (plasma membrane) have a

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

Answer: A

300. Which of the following is not a necessary component of translation?

A. Anticodon
B. mRNA
C. Ligase
D. Amino acid

Answer: C

301. A polysome could be best described as

A. an active site of DNA synthesis.

B. an active site of protein synthesis.
C. an active site of lipid synthesis.
D. all of the above.

Answer: B
302. Eukaryotic mRNA binding to the ribosomes is facilitated by __________ .

A. the Shine Dalgarno sequence

B. the 7-methyl guanosine cap
C. tRNA
D. poly A tail

Answer: B

303. Amino acids are joined together into a protein chain by which of the following?

A. Transfer RNA
B. DNA polymerase
C. Hydrogen bonds
D. Messenger RNA

Answer: A

304. Phosphorus is taken up by the cell during the process of

A. carbohydrate synthesis.
B. protein synthesis,
C. lipid synthesis.
D. ATP synthesis.

Answer: D

305. 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

A. 10 amino acids/sec
B. 17 amino acids/sec
C. 25 amino acids/sec
D. 50 amino acids/sec

Answer: B
306. The site of protein synthesis is

A. Ribosome
B. Nucleus
C. Endoplasmic reticulum
D. Chromosome

Answer: A

307. The structure in a bacterium that indicates an active site for protein synthesis is

A. a chromosome.
B. a cell membrane,
C. a flagellum.
D. a polysome.

Answer: D

308. The lac operon contains the z, y and a structural genes

A. encoding p-galactosidase, galactose permeases and thio-galactosidase transacetylase

respectively
B. encoding p-galactosidase and galactose permeases
C. encoding P-galactosidase only
D. None of the above

Answer: A

309. Proteins contain __________ different amino acids, whereas DNA and RNA are
composed of __________ different nucleotides

A. 20,64 B. 3,20
C. 4,20 D. 20,4

Answer: D
310. Which of the following is not necessary for protein synthesis to occur, once
transcription is completed?

A. tRNA
B. Ribosomes
C. mRNA
D. DNA

Answer: D

311. Ribosomes select the correct tRNAs

A. 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

Answer: B

312. Signal peptide protein removal that is translocated across a membrane is

accomplished by

A. fMet aminopeptidase
B. trypsin
C. signal peptidase
D. chymotrypsin

Answer: C

313. The direction of amino acid transfer to the growing polypeptide chain is

A. 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

Answer: B
314. The pathway of a tRNA during polypeptide elongation on the ribosome is

A. 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

Answer: A

315. Which of the following has unusual bases?

A. mRNA
B. tRNA
C. rRNA
D. hnRNA

Answer: B

316. The site on a bacterial chromosome that marks the termination point for
chromosome replication is called

A. ter
B. a stop codon.
C. a stem-loop
D. pau

Answer: A

317. Degenerated codon differs mostly in

A. the identities of their second base

B. the identities of their third base
C. the wobble position
D. both (b) and (c)

Answer: D
318. Translation in prokaryotes begins by the formation of a 30S initiation complex
between the

A. 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

Answer: A

319. The anticodon of tRNA

A. binds to rRNA
B. binds to an amino acid
C. binds to the Shine Dalgarno sequence
D. binds to an mRNA codon

Answer: D

320. The peptidyl transferase reaction occurs

A. on the large subunit

B. on the small subunit
C. between the subunit
D. none of these

Answer: A

321. Processive synthesis is a characteristic feature of

A. all DNA polymerases.

B. DNA Pol III at a replication fork.
C. removal of RNA primers on Okasaki fragments.
D. DNA mismatch repair

Answer: B
322. Which site of the tRNA molecule binds to the mRNA molecule?

A. Anticodon
B. Codon
C. Amino acid
D. 5 prime end

Answer: A