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
E.coli ACP has its molecular weight as around
A. 9000
B. 19000
C. 39000
D. 90000
Question 2
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
Question 3
Who discovered vitamin C (ascorbic acid)?
A. Paul Berg
B. Linus Pauling
C. Albert Szent-Gyorgyi
D. Kerry Mull is
Question 4
An example of a digestive hormone is
A. lipase
B. pepsin
C. amylase
D. gastrin
Question 5
Which of the following are reduced coenzymes?
A. NADH and FADH2
B. NAD+ and FAD
C. ATP and GTP
D. Coenzyme A and ubiquinone
Question 6
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+)
Question 7
Which of these is a vitamin A precursor?
A. Cobalamin
B. Pyridoxine
C. Beta-Carotene
D. Thiamine
Question 8
Which of these is a symptom of vitamin A deficiency?
A. Osteoporosis
B. Impaired taste perception
C. Blindness
D. Impaired blood clotting
Question 9
Lipoic acid is a co-factor of the
A. pyruvic dehydrogenase
B. α-ketoglutaric dehydrogenase
C. both (a) and (b)
D. di-hydroorotate dehydrogenase
Question 10
In one iron-metalloflavoprotein, the iron is present as a
A. heme-protein
B. nonheme type
C. both (a) and (b)
D. flavin moiety
Question 11
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
Question 12
A deficiency of thiamin produces the disease known as
A. beri-beri
B. scurvy
C. cataract
D. anemia
Question 13
The absence of ascorbic acid in the human diet gives rise to
A. rickets
B. pernicious anemia
C. cataract
D. beri-beri
Question 14
Vitamin B12 is useful in the prevention and treatment of
A. pernicious anemia
B. scurvy
C. cataract
D. beri-beri
Question 15
Vitamin-D deficiency can cause
A. rickets
B. pernicious anemia
C. cataract
D. beri-beri
Question 16
A deficiency of niacin causes
A. pellagra
B. scurvy
C. cataract
D. anemia
Question 17
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
Question 18
Vitamin-C is considered as a
A. water soluble
B. fat soluble
C. fat and water soluble
D. none of these
Question 19
A deficiency of Vitamin K results in a decreased level of
A. prothrombin
B. thrombin
C. fibrin
D. fibrinogen
Question 20
Which of these molecules is vitamin H?
A. Biotin
B. Carnitine
C. Folic acid
D. None of these
Question 21
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
Question 22
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
Question 23
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
Question 24
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
Question 25
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
Question 26
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
Question 27
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
Question 28
What compound of raw egg white causes a syndrome similar to vitamin B deficiency?
A. Avidin
B. Betabindin
C. Ovalbumin
D. Albumin
Question 29
Lipoic acid exists in
A. oxidized form
B. reduced form
C. oxidized and reduced form both
D. none of these
Question 30
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
Question 31
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
Question 32
Ascorbic acid acts as an
A. reducing agent
B. oxidizing agent
C. oxidizing and reducing agent both
D. none of the above
Question 33
Vitamin B12 (Cobalamin) is only synthesized by
A. fishes
B. micro-organisms
C. plants
D. animals
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
Question 35
The vitamin riboflavin is part of the __________ molecule.
A. ferredoxin
B. FAD
C. pyridoxal phosphat
D. pyrophosphate
Question 36
Which of the following compounds/(s) belong/(s) to the vitamin B6 group?
A. Pyridoxal
B. Pyridoxine
C. Pyridoxamine
D. All of these
Question 37
The vitamin niacin is part of the __________ molecule.
A. ferredoxin
B. pyridoxal phosphate
C. pyrophosphate
D. NAD+
Question 38
Acyl carrier protein (ACP) plays an important role in the biosynthesis of
A. fatty acids
B. amino acids
C. sugars
D. carbohydrates
Question 39
Which of these hormones is a catecholamine?
A. Follitropin
B. Norepinephrine
C. Tetraiodothyronine
D. Tetrahydrofolate
Question 40
An enzyme, L-folate reductase reduces folic acid to
A. hydrofolic acid
B. dihydrofolic acid
C. trihydrofolic acid
D. tetrahydrofolic acid
Question 41
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
Question 42
A fat-soluble vitamin that regulates blood clotting is
A. vitamin A
B. vitamin K
C. vitamin C
D. niacin
Question 43
The symptoms of retinol excess are
A. bone fragility
B. nausea
C. weakness
D. all of these
Question 44
An early sign of retinol deficiencies in man is
A. night blindness
B. keratinization
C. xeropthalmia
D. none of these
Question 45
What metal ion is specifically bound by vitamin B12?
A. Cobalt
B. Copper
C. Zinc
D. Iron