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Biochemistry MCQS PAPER SET 4
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1. Which of the following is not a significant biological oxidizing agent?
FAD
Fe3+
O2
NAD+
2. How many CO2 molecules are exhaled for each O2 molecule utilized in cellular respiration?
1
3
6
12
3. What happens after glycolysis when oxygen is available as an electron acceptor?
Pyruvate is formed
NADH is produced
Fermentation
Oxidative phosphorylation
4. Lactic acid is produced by human muscles during strenuous exercise because of lack of
oxygen
NAD+
glucose
ADP and Pi
5. Which of the following is correct sequence of processes in the oxidation of glucose?
Krebs cycle - glycolysis - electron transport
Glycolysis - Krebs cycle - eletron transport
Electron transport - Krebs cycle - glycolysis
Krebs cycle - electron transport - glycolysis
6. In electron transport, electrons ultimately pass to
ADP
cytochrome b
oxygen
none of these
7. The complete oxidation of glucose yields usable energy in the form of
FADH2
coenzyme A
ATP
pyruvic acid
8. During electron transport, protons are pumped out of the mitochondrion at each of the major sites except for
complex I
complex II
complex III
complex IV
9. The aerobic breakdown of glucose known as respiration involves
electron transport phosphorylation
glycolysis
Krebs Cycle
all of the above
10. In aerobic respiration, the compound that enters a mitochondrion is
acetyl CoA
pyruvate
phosphoglyceraldehyde
oxaloacetate
11. How many molecules of ATP are hydrolysed to form two molecule of ammonia?
10
5
16
15
12. The nitrogen atoms of urea produced in the urea cycle are derived from
nitrate
ammonia and aspartic acid
nitrite
ammonia
13. The products of urea cycle are
1 molecule of urea, 1 molecule of ammonia, 1 molecule of ATP and 1 molecule of fumaric acid
1 molecule of fumaric acid, 1 molecule of urea, 1 molecule of AMP, 2 molecules of ADP
1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of fumaric acid, 1 molecule of ATP
None of the above
14. Nitrate reduction can be carried out by
only microorganism
plant and microorganism
only plants
none of these
15. Which of the following is used as carbon atom source while producing urea in the urea cycle?
Arginine
Aspartic acid
Carbon dioxide
Glucose
16. Which of the following amino acid do not fall under the category of essential amino acid?
Histidine
Leucine
Glycine
Methionine
17. Urea cycle converts
ammonia into a less toxic form
ketoacids into amino acids
amino acids into ketoacids
none of these
18. The inputs to one cycle of the urea cycle are
1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of carbon dioxide, 3 molecules of ATP
1 molecule of urea, 1 molecule of ammonia, 3 molecules of ATP and 1 molecule of fumaric acid
1 molecule of fumaric acid, 1 molecule of urea, 3 molecules of AMP
None of the above
19. The symptoms of retinol excess are
bone fragility
nausea
weakness
all of these
20. Main function of insulin hormone is to
increase glycogen in liver
decrease glycogen in liver
increase blood sugar
decrease blood sugar
21. Ascorbic acid acts as an
reducing agent
oxidizing agent
oxidizing and reducing agent both
none of the above
22. A deficiency of thiamin produces the disease known as
beri-beri
scurvy
cataract
anemia
23. Acyl carrier protein (ACP) plays an important role in the biosynthesis
fatty acids
amino acids
sugars
carbohydrates
24. Vitamin B12 (Cobalamin) is only synthesized by
fishes
micro-organisms
plants
animals
25. Which of the following are reduced coenzymes?
NADH and FADH2
NAD+ and FAD
ATP and GTP
Coenzyme A and ubiquinone
26. The absence of ascorbic acid in the human diet gives rise to
rickets
pernicious anemia
cataract
beri-beri
27. Vitamins are essential because the organism
can't synthesize these compounds at all
can synthesize these compounds partially
can't synthesize these compounds in the adequate amounts
none of the above
28. The prosthetic group biotin is a carrier of which type of molecule?
Activated carbon dioxide (CO2)
Ammonia
Methyl group
Sulfhydryl group
29. Lipoic acid exists in
oxidized form
reduced form
oxidized and reduced form both
none of these
30. Vitamin B12 is useful in the prevention and treatment of
pernicious anemia
scurvy
cataract
beri-beri
31. An example of a digestive hormone is
lipase
pepsin
amylase
gastrin
32. In the co-enzyme B12the position occupied by a cyanide ion in vitamin B12 is bonded directly to the __________ of the ribose of adenosine.
adenine
5-6 dimethylbenzimidazole
hydroxycobalamin
cyanocobalamin
33. The reductant, NADH, transfers the electrons via a flavo-proteins to the specific disulfide (S-S) protein to form a dithiol (SH,SH) protein which converts vitamin
B12(Co2+)to B12(Co)
B12(Co) to B12(Co2+)
B12(Co2+)to B12(Co+)
B12(Co+)to B12(Co2+)
34. An early sign of retinol deficiencies in man is
night blindness
keratinization
xeropthalmia
none of these
35. An enzyme, L-folate reductase reduces folic acid to
hydrofolic acid
dihydrofolic acid
trihydrofolic acid
tetrahydrofolic acid
36. What compound of raw egg white causes a syndrome similar to vitamin B deficiency?
Avidin
Betabindin
Ovalbumin
Albumin
37. The disease Beriberi is due to a dietary deficiency in
vitamin B1 (thiamine)
vitamin B2 (riboflavin)
vitamin B6 (pyridoxine)
vitamin B12
38. Which of these is a symptom of vitamin A deficiency?
Osteoporosis
Impaired taste perception
Blindness
Impaired blood clotting
39. Vitamin-C is considered as a
water soluble
fat soluble
fat and water soluble
none of these
40. The vitamin niacin is part of the __________ molecule.
ferredoxin
pyridoxal phosphate
pyrophosphate
NAD+
41. Which of these hormones is a catecholamine?
Follitropin
Norepinephrine
Tetraiodothyronine
Tetrahydrofolate
42. Dihydroorotate dehydrogenase contains
4 flavins and 4 atoms of iron per molecule
2 flavins and 4 atoms of iron per molecule
2 flavins and 2 atoms of iron per molecule
4 flavins and 2 atoms of iron per molecule
43. E.coli ACP has its molecular weight as around
9000
19000
39000
90,000
44. The vitamin riboflavin is part of the __________ molecule.
ferredoxin
FAD
pyridoxal phosphat
pyrophosphate
45. The most prominent role that tocopherol has in in-vitro systems is as a strong
antioxidants
reducing agent
oxidizing agent
all of these
46. Biotin occurs mainly in combined forms bound to protein through
ε-N-lysine moiety
ε-S-lysine moiety
ε-N-biotinyl-L-lysine
ε-N-lipoyl - L-lysine
47. Lipoic acid is a co-factor of the
pyruvic dehydrogenase
α-ketoglutaric dehydrogenase
both (a) and (b)
di-hydroorotate dehydrogenase
48. β-carotene together with α-carotene, γ-carotene and cryptoxanthine are synthesized by
plants
animal
plants and animals both
none of these
49. Vitamin-D deficiency can cause
rickets
pernicious anemia
cataract
beri-beri
50. The most prominent role that tocopherol has in in-vitro systems is as a strong
antioxidants
reducing agent
oxidizing agent
all of these
51. Biotin occurs mainly in combined forms bound to protein through
ε-N-lysine moiety
ε-S-lysine moiety
ε-N-biotinyl-L-lysine
ε-N-lipoyl - L-lysine
52. Lipoic acid is a co-factor of the
pyruvic dehydrogenase
α-ketoglutaric dehydrogenase
both (a) and (b)
di-hydroorotate dehydrogenase
53. β-carotene together with α-carotene, γ-carotene and cryptoxanthine are synthesized by
plants
animal
plants and animals both
none of these
54. A deficiency of Vitamin K results in a decreased level of
prothrombin
thrombin
fibrin
fibrinogen
55. The vitamin riboflavin, which occurs as a yellow pigment in egg yolk and milk become
colorless on reduction with Zn in acid and regained its color on re-oxidation
colorless on oxidation and regained its color on reduction with Zn in acid
more deep in color on reduction with Zn in acid and regained its color on re-oxidation
more deep in color on oxidation and regained its color on reduction with Zn in acid
56. Which of the following compounds/(s) belong/(s) to the vitamin B6 group?
Pyridoxal
Pyridoxine
Pyridoxamine
All of these
57. What metal ion is specifically bound by vitamin B12?
Cobalt
Copper
Zinc
Iron
58. A fat-soluble vitamin that regulates blood clotting is
vitamin A
vitamin K
vitamin C
niacin
59. Which of these is a vitamin A precursor?
Cobalamin
Pyridoxine
Beta-Carotene
Thiamine
60. In one iron-metalloflavoprotein, the iron is present as a
heme-protein
nonheme type
both (a) and (b)
flavin moiety
61. Vitamin K1 was first isolated from alfalalfa and has the phytyl side chain consisting of
four isoprene units
six isoprene units
nine isoprene units
four isoprene units
62. Which of these molecules is vitamin H?
Biotin
Carnitine
Folic acid
None of these
63. The occurrence of metals such as iron or molybdenum in some flavoproteins can
stabilize the semiquinone
de-stabilize the semiquinone
form chelation
all of these
64. Models of end-linked Osaka VI Fibrinogen dimers, a bilayer dimer is linked at
both ends by one disulfide bond
either end via two disulfide bonds
either end via a single disulfide bond
both ends by two disulfide bonds
65. A deficiency of niacin causes
pellagra
scurvy
cataract
anemia
66. Selenium is an essential component of the enzyme glutathione peroxidase which
scavenges toxic hydoperoxycompounds in tissues
reduces toxic hydoperoxycompounds in tissues
oxidizes toxic hydoperoxycompounds in tissues
none of the above
67. Who discovered vitamin C (ascorbic acid)?
Paul Berg
Linus Pauling
Albert Szent-Gyorgyi
Kerry Mull is
68. Molar absorbtivities of compounds exhibiting charge transfer absorption are
small
moderate
large
none of these
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