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Vitamins and Coenzymes MCQ Questions & Answers

Vitamins and Coenzymes MCQs : This section focuses on the "Vitamins and Coenzymes". These Multiple Choice Questions (MCQs) should be practiced to improve the Vitamins and Coenzymes skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

Which of these is a vitamin A precursor?

A. Cobalamin
B. Pyridoxine
C. Beta-Carotene
D. Thiamine

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Question 2

Vitamin B12 is useful in the prevention and treatment of

A. pernicious anemia
B. scurvy
C. cataract
D. beri-beri

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Question 3

Lipoic acid exists in

A. oxidized form
B. reduced form
C. oxidized and reduced form both
D. none of these

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Question 4

The symptoms of retinol excess are

A. bone fragility
B. nausea
C. weakness
D. all of these

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Question 5

What metal ion is specifically bound by vitamin B12?

A. Cobalt
B. Copper
C. Zinc
D. Iron

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Question 6

Main function of insulin hormone is to

A. increase glycogen in liver
B. decrease glycogen in liver
C. increase blood sugar
D. decrease blood sugar

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Question 7

A deficiency of thiamin produces the disease known as

A. beri-beri
B. scurvy
C. cataract
D. anemia

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Question 8

The vitamin niacin is part of the __________ molecule.

A. ferredoxin
B. pyridoxal phosphate
C. pyrophosphate
D. NAD+

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Question 9

Dihydroorotate dehydrogenase contains

A. 4 flavins and 4 atoms of iron per molecule
B. 2 flavins and 4 atoms of iron per molecule
C. 2 flavins and 2 atoms of iron per molecule
D. 4 flavins and 2 atoms of iron per molecule

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Question 10

An enzyme, L-folate reductase reduces folic acid to

A. hydrofolic acid
B. dihydrofolic acid
C. trihydrofolic acid
D. tetrahydrofolic acid

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Question 11

Vitamin K1 was first isolated from alfalalfa and has the phytyl side chain consisting of

A. four isoprene units
B. six isoprene units
C. nine isoprene units
D. four isoprene units

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Question 12

Models of end-linked Osaka VI Fibrinogen dimers, a bilayer dimer is linked at

A. both ends by one disulfide bond
B. either end via two disulfide bonds
C. either end via a single disulfide bond
D. both ends by two disulfide bonds

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Question 13

A deficiency of niacin causes

A. pellagra
B. scurvy
C. cataract
D. anemia

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Question 14

An example of a digestive hormone is

A. lipase
B. pepsin
C. amylase
D. gastrin

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Question 15

Vitamin B12 (Cobalamin) is only synthesized by

A. fishes
B. micro-organisms
C. plants
D. animals

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Question 16

Vitamin-D deficiency can cause

A. rickets
B. pernicious anemia
C. cataract
D. beri-beri

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Question 17

Which of these is a symptom of vitamin A deficiency?

A. Osteoporosis
B. Impaired taste perception
C. Blindness
D. Impaired blood clotting

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Question 18

Biotin occurs mainly in combined forms bound to protein through

A. ε-N-lysine moiety
B. ε-S-lysine moiety
C. ε-N-biotinyl-L-lysine
D. ε-N-lipoyl - L-lysine

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Question 19

A deficiency of Vitamin K results in a decreased level of

A. prothrombin
B. thrombin
C. fibrin
D. fibrinogen

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Question 20

Vitamin-C is considered as a

A. water soluble
B. fat soluble
C. fat and water soluble
D. none of these

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Question 21

Which of these hormones is a catecholamine?

A. Follitropin
B. Norepinephrine
C. Tetraiodothyronine
D. Tetrahydrofolate

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Question 22

E.coli ACP has its molecular weight as around

A. 9000
B. 19000
C. 39000
D. 90000

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Question 23

Which of the following are reduced coenzymes?

A. NADH and FADH2
B. NAD+ and FAD
C. ATP and GTP
D. Coenzyme A and ubiquinone

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Question 24

Ascorbic acid acts as an

A. reducing agent
B. oxidizing agent
C. oxidizing and reducing agent both
D. none of the above

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Question 25

What compound of raw egg white causes a syndrome similar to vitamin B deficiency?

A. Avidin
B. Betabindin
C. Ovalbumin
D. Albumin

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Question 26

Who discovered vitamin C (ascorbic acid)?

A. Paul Berg
B. Linus Pauling
C. Albert Szent-Gyorgyi
D. Kerry Mull is

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Question 27

Lipoic acid is a co-factor of the

A. pyruvic dehydrogenase
B. α-ketoglutaric dehydrogenase
C. both (a) and (b)
D. di-hydroorotate dehydrogenase

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Question 28

A fat-soluble vitamin that regulates blood clotting is

A. vitamin A
B. vitamin K
C. vitamin C
D. niacin

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Question 29

The disease Beriberi is due to a dietary deficiency in

A. vitamin B1 (thiamine)
B. vitamin B2 (riboflavin)
C. vitamin B6 (pyridoxine)
D. vitamin B12

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Question 30

The occurrence of metals such as iron or molybdenum in some flavoproteins can

A. stabilize the semiquinone
B. de-stabilize the semiquinone
C. form chelation
D. all of these

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Question 31

The prosthetic group biotin is a carrier of which type of molecule?

A. Activated carbon dioxide (CO2)
B. Ammonia
C. Methyl group
D. Sulfhydryl group

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Question 32

An early sign of retinol deficiencies in man is

A. night blindness
B. keratinization
C. xeropthalmia
D. none of these

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Question 33

The absence of ascorbic acid in the human diet gives rise to

A. rickets
B. pernicious anemia
C. cataract
D. beri-beri

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Question 34

β-carotene together with α-carotene, γ-carotene and cryptoxanthine are synthesized by

A. plants
B. animal
C. plants and animals both
D. none of these

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Question 35

Which of these molecules is vitamin H?

A. Biotin
B. Carnitine
C. Folic acid
D. None of these

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Question 36

The most prominent role that tocopherol has in in-vitro systems is as a strong

A. antioxidants
B. reducing agent
C. oxidizing agent
D. all of these

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Question 37

Selenium is an essential component of the enzyme glutathione peroxidase which

A. scavenges toxic hydoperoxycompounds in tissues
B. reduces toxic hydoperoxycompounds in tissues
C. oxidizes toxic hydoperoxycompounds in tissues
D. none of the above

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Question 38

The vitamin riboflavin is part of the __________ molecule.

A. ferredoxin
B. FAD
C. pyridoxal phosphat
D. pyrophosphate

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Question 39

The vitamin riboflavin, which occurs as a yellow pigment in egg yolk and milk become

A. colorless on reduction with Zn in acid and regained its color on re-oxidation
B. colorless on oxidation and regained its color on reduction with Zn in acid
C. more deep in color on reduction with Zn in acid and regained its color on re-oxidation
D. more deep in color on oxidation and regained its color on reduction with Zn in acid

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Question 40

In the co-enzyme B12the position occupied by a cyanide ion in vitamin B12 is bonded directly to the __________ of the ribose of adenosine.

A. adenine
B. 5-6 dimethylbenzimidazole
C. hydroxycobalamin
D. cyanocobalamin

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Question 41

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

A. B12(Co2+)to B12(Co)
B. B12(Co) to B12(Co2+)
C. B12(Co2+)to B12(Co+)
D. B12(Co+)to B12(Co2+)

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Question 42

Which of the following compounds/(s) belong/(s) to the vitamin B6 group?

A. Pyridoxal
B. Pyridoxine
C. Pyridoxamine
D. All of these

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Question 43

In one iron-metalloflavoprotein, the iron is present as a

A. heme-protein
B. nonheme type
C. both (a) and (b)
D. flavin moiety

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Question 44

Acyl carrier protein (ACP) plays an important role in the biosynthesis of

A. fatty acids
B. amino acids
C. sugars
D. carbohydrates

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Question 45

Vitamins are essential because the organism

A. can't synthesize these compounds at all
B. can synthesize these compounds partially
C. can't synthesize these compounds in the adequate amounts
D. none of the above

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