Vitamins and Coenzymes

Q1: Who discovered vitamin C (ascorbic acid)?

A Paul Berg

B Linus Pauling

C Albert Szent-Gyorgyi

D Kerry Mull is

ANS:C - Albert Szent-Gyorgyi

No answer description is available.

Q2: 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

ANS:A - Activated carbon dioxide (CO2)

No answer description is available.

Q3: 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

ANS:A - can't synthesize these compounds at all

No answer description is available.

Q4: Vitamin-D deficiency can cause

A rickets

B pernicious anemia

C cataract

D beri-beri

ANS:A - rickets

No answer description is available.

Q5: 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

ANS:A - scavenges toxic hydoperoxycompounds in tissues

No answer description is available.

Q6: Which of these is a symptom of vitamin A deficiency?

A Osteoporosis

B Impaired taste perception

C Blindness

D Impaired blood clotting

ANS:C - Blindness

No answer description is available.

Q7: 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

ANS:A - four isoprene units

No answer description is available.

Q8: E.coli ACP has its molecular weight as around

A 9000

B 19000

C 39000

D 90,000

ANS:A - 9000

No answer description is available.

Q9: 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

ANS:D - decrease blood sugar

No answer description is available.

Q10: Vitamin B12 is useful in the prevention and treatment of

A pernicious anemia

B scurvy

C cataract

D beri-beri

ANS:A - pernicious anemia

No answer description is available.

Q11: Which of these molecules is vitamin H?

A Biotin

B Carnitine

C Folic acid

D None of these

ANS:A - Biotin

No answer description is available.

Q12: 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+)

ANS:C - B12(Co2+)to B12(Co+)

No answer description is available.

Q13: 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

ANS:A - plants

No answer description is available.

Q14: 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

ANS:A - stabilize the semiquinone

No answer description is available.

Q15: An example of a digestive hormone is

A lipase

B pepsin

C amylase

D gastrin

ANS:D - gastrin

No answer description is available.

Q16: 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

ANS:A - adenine

No answer description is available.

Q17: 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

ANS:A - vitamin B1 (thiamine)

No answer description is available.

Q18: Vitamin B12 (Cobalamin) is only synthesized by

A fishes

B micro-organisms

C plants

D animals

ANS:B - micro-organisms

No answer description is available.

Q19: Lipoic acid is a co-factor of the

A pyruvic dehydrogenase

B α-ketoglutaric dehydrogenase

C both (a) and (b)

D di-hydroorotate dehydrogenase

ANS:C - both (a) and (b)

No answer description is available.

Q20: A fat-soluble vitamin that regulates blood clotting is

A vitamin A

B vitamin K

C vitamin C

D niacin

ANS:B - vitamin K

No answer description is available.

Q21: A deficiency of thiamin produces the disease known as

A beri-beri

B scurvy

C cataract

D anemia

ANS:A - beri-beri

No answer description is available.

Q22: An early sign of retinol deficiencies in man is

A night blindness

B keratinization

C xeropthalmia

D none of these

ANS:A - night blindness

No answer description is available.

Q23: The vitamin niacin is part of the __________ molecule.

A ferredoxin

B pyridoxal phosphate

C pyrophosphate

D NAD+

ANS:D - NAD+

No answer description is available.

Q24: 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

ANS:A - 4 flavins and 4 atoms of iron per molecule

No answer description is available.

Q25: The absence of ascorbic acid in the human diet gives rise to

A rickets

B pernicious anemia

C cataract

D beri-beri

ANS:B - pernicious anemia

No answer description is available.

Q26: 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

ANS:A - antioxidants

No answer description is available.

Q27: Ascorbic acid acts as an

A reducing agent

B oxidizing agent

C oxidizing and reducing agent both

D none of the above

ANS:A - reducing agent

No answer description is available.

Q28: Which of these hormones is a catecholamine?

A Follitropin

B Norepinephrine

C Tetraiodothyronine

D Tetrahydrofolate

ANS:B - Norepinephrine

No answer description is available.

Q29: 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

ANS:A - ε-N-lysine moiety

No answer description is available.

Q30: Vitamin-C is considered as a

A water soluble

B fat soluble

C fat and water soluble

D none of these

ANS:A - water soluble

No answer description is available.

Q31: The vitamin riboflavin is part of the __________ molecule.

A ferredoxin

B FAD

C pyridoxal phosphat

D pyrophosphate

ANS:B - FAD

No answer description is available.

Q32: Acyl carrier protein (ACP) plays an important role in the biosynthesis of

A fatty acids

B amino acids

C sugars

D carbohydrates

ANS:A - fatty acids

No answer description is available.

Q33: In one iron-metalloflavoprotein, the iron is present as a

A heme-protein

B nonheme type

C both (a) and (b)

D flavin moiety

ANS:A - heme-protein

No answer description is available.

Q34: Lipoic acid exists in

A oxidized form

B reduced form

C oxidized and reduced form both

D none of these

ANS:C - oxidized and reduced form both

No answer description is available.

Q35: What metal ion is specifically bound by vitamin B12?

A Cobalt

B Copper

C Zinc

D Iron

ANS:D - Iron

No answer description is available.

Q36: What compound of raw egg white causes a syndrome similar to vitamin B deficiency?

A Avidin

B Betabindin

C Ovalbumin

D Albumin

ANS:A - Avidin

No answer description is available.

Q37: Which of these is a vitamin A precursor?

A Cobalamin

B Pyridoxine

C Beta-Carotene

D Thiamine

ANS:C - Beta-Carotene

No answer description is available.

Q38: The symptoms of retinol excess are

A bone fragility

B nausea

C weakness

D all of these

ANS:D - all of these

No answer description is available.

Q39: 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

ANS:A - colorless on reduction with Zn in acid and regained its color on re-oxidation

No answer description is available.

Q40: A deficiency of niacin causes

A pellagra

B scurvy

C cataract

D anemia

ANS:A - pellagra

No answer description is available.

Q41: A deficiency of Vitamin K results in a decreased level of

A prothrombin

B thrombin

C fibrin

D fibrinogen

ANS:A - prothrombin

No answer description is available.

Q42: An enzyme, L-folate reductase reduces folic acid to

A hydrofolic acid

B dihydrofolic acid

C trihydrofolic acid

D tetrahydrofolic acid

ANS:B - dihydrofolic acid

No answer description is available.

Q43: Which of the following compounds/(s) belong/(s) to the vitamin B6 group?

A Pyridoxal

B Pyridoxine

C Pyridoxamine

D All of these

ANS:D - All of these

No answer description is available.

Q44: Which of the following are reduced coenzymes?

A NADH and FADH2

B NAD+ and FAD

C ATP and GTP

D Coenzyme A and ubiquinone

ANS:A - NADH and FADH2

No answer description is available.

Q45: 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

ANS:D - both ends by two disulfide bonds

No answer description is available.



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