R4RIN – MCQs, Mock Tests | Biochemistry Biochemistry MCQS PAPER SET 4

Which of the following is not a significant biological oxidizing agent?

1. FAD
2. Fe3+
3. O2
4. NAD+

✅ Correct Answer: 2

How many CO2 molecules are exhaled for each O2 molecule utilized in cellular respiration?

1. 1
2. 3
3. 6
4. 12

✅ Correct Answer: 1

What happens after glycolysis when oxygen is available as an electron acceptor?

1. Pyruvate is formed
2. NADH is produced
3. Fermentation
4. Oxidative phosphorylation

✅ Correct Answer: 2

Lactic acid is produced by human muscles during strenuous exercise because of lack of

1. oxygen
2. NAD+
3. glucose
4. ADP and Pi

✅ Correct Answer: 1

Which of the following is correct sequence of processes in the oxidation of glucose?

1. Krebs cycle - glycolysis - electron transport
2. Glycolysis - Krebs cycle - eletron transport
3. Electron transport - Krebs cycle - glycolysis
4. Krebs cycle - electron transport - glycolysis

✅ Correct Answer: 2

In electron transport, electrons ultimately pass to

1. ADP
2. cytochrome b
3. oxygen
4. none of these

✅ Correct Answer: 3

The complete oxidation of glucose yields usable energy in the form of

1. FADH2
2. coenzyme A
3. ATP
4. pyruvic acid

✅ Correct Answer: 3

During electron transport, protons are pumped out of the mitochondrion at each of the major sites except for

1. complex I
2. complex II
3. complex III
4. complex IV

✅ Correct Answer: 2

The aerobic breakdown of glucose known as respiration involves

1. electron transport phosphorylation
2. glycolysis
3. Krebs Cycle
4. all of the above

✅ Correct Answer: 4

In aerobic respiration, the compound that enters a mitochondrion is

1. acetyl CoA
2. pyruvate
3. phosphoglyceraldehyde
4. oxaloacetate

✅ Correct Answer: 2

How many molecules of ATP are hydrolysed to form two molecule of ammonia?

1. 10
2. 5
3. 16
4. 15

✅ Correct Answer: 3

The nitrogen atoms of urea produced in the urea cycle are derived from

1. nitrate
2. ammonia and aspartic acid
3. nitrite
4. ammonia

✅ Correct Answer: 2

The products of urea cycle are

1. 1 molecule of urea, 1 molecule of ammonia, 1 molecule of ATP and 1 molecule of fumaric acid
2. 1 molecule of fumaric acid, 1 molecule of urea, 1 molecule of AMP, 2 molecules of ADP
3. 1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of fumaric acid, 1 molecule of ATP
4. None of the above

✅ Correct Answer: 2

Nitrate reduction can be carried out by

1. only microorganism
2. plant and microorganism
3. only plants
4. none of these

✅ Correct Answer: 2

Which of the following is used as carbon atom source while producing urea in the urea cycle?

1. Arginine
2. Aspartic acid
3. Carbon dioxide
4. Glucose

✅ Correct Answer: 3

Which of the following amino acid do not fall under the category of essential amino acid?

1. Histidine
2. Leucine
3. Glycine
4. Methionine

✅ Correct Answer: 3

Urea cycle converts

1. ammonia into a less toxic form
2. ketoacids into amino acids
3. amino acids into ketoacids
4. none of these

✅ Correct Answer: 1

The inputs to one cycle of the urea cycle are

1. 1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of carbon dioxide, 3 molecules of ATP
2. 1 molecule of urea, 1 molecule of ammonia, 3 molecules of ATP and 1 molecule of fumaric acid
3. 1 molecule of fumaric acid, 1 molecule of urea, 3 molecules of AMP
4. None of the above

✅ Correct Answer: 1

The symptoms of retinol excess are

1. bone fragility
2. nausea
3. weakness
4. all of these

✅ Correct Answer: 4

Main function of insulin hormone is to

1. increase glycogen in liver
2. decrease glycogen in liver
3. increase blood sugar
4. decrease blood sugar

✅ Correct Answer: 4

Ascorbic acid acts as an

1. reducing agent
2. oxidizing agent
3. oxidizing and reducing agent both
4. none of the above

✅ Correct Answer: 1

A deficiency of thiamin produces the disease known as

1. beri-beri
2. scurvy
3. cataract
4. anemia

✅ Correct Answer: 1

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

1. fatty acids
2. amino acids
3. sugars
4. carbohydrates

✅ Correct Answer: 1

Vitamin B12 (Cobalamin) is only synthesized by

1. fishes
2. micro-organisms
3. plants
4. animals

✅ Correct Answer: 2

Which of the following are reduced coenzymes?

1. NADH and FADH2
2. NAD+ and FAD
3. ATP and GTP
4. Coenzyme A and ubiquinone

✅ Correct Answer: 1

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

1. rickets
2. pernicious anemia
3. cataract
4. beri-beri

✅ Correct Answer: 2

Vitamins are essential because the organism

1. can't synthesize these compounds at all
2. can synthesize these compounds partially
3. can't synthesize these compounds in the adequate amounts
4. none of the above

✅ Correct Answer: 1

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

1. Activated carbon dioxide (CO2)
2. Ammonia
3. Methyl group
4. Sulfhydryl group

✅ Correct Answer: 1

Lipoic acid exists in

1. oxidized form
2. reduced form
3. oxidized and reduced form both
4. none of these

✅ Correct Answer: 3

Vitamin B12 is useful in the prevention and treatment of

1. pernicious anemia
2. scurvy
3. cataract
4. beri-beri

✅ Correct Answer: 1

An example of a digestive hormone is

1. lipase
2. pepsin
3. amylase
4. gastrin

✅ Correct Answer: 4

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

1. adenine
2. 5-6 dimethylbenzimidazole
3. hydroxycobalamin
4. cyanocobalamin

✅ Correct Answer: 1

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

1. B12(Co2+)to B12(Co)
2. B12(Co) to B12(Co2+)
3. B12(Co2+)to B12(Co+)
4. B12(Co+)to B12(Co2+)

✅ Correct Answer: 3

An early sign of retinol deficiencies in man is

1. night blindness
2. keratinization
3. xeropthalmia
4. none of these

✅ Correct Answer: 1

An enzyme, L-folate reductase reduces folic acid to

1. hydrofolic acid
2. dihydrofolic acid
3. trihydrofolic acid
4. tetrahydrofolic acid

✅ Correct Answer: 2

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

1. Avidin
2. Betabindin
3. Ovalbumin
4. Albumin

✅ Correct Answer: 1

The disease Beriberi is due to a dietary deficiency in

1. vitamin B1 (thiamine)
2. vitamin B2 (riboflavin)
3. vitamin B6 (pyridoxine)
4. vitamin B12

✅ Correct Answer: 1

Which of these is a symptom of vitamin A deficiency?

1. Osteoporosis
2. Impaired taste perception
3. Blindness
4. Impaired blood clotting

✅ Correct Answer: 3

Vitamin-C is considered as a

1. water soluble
2. fat soluble
3. fat and water soluble
4. none of these

✅ Correct Answer: 1

The vitamin niacin is part of the __________ molecule.

1. ferredoxin
2. pyridoxal phosphate
3. pyrophosphate
4. NAD+

✅ Correct Answer: 4

Which of these hormones is a catecholamine?

1. Follitropin
2. Norepinephrine
3. Tetraiodothyronine
4. Tetrahydrofolate

✅ Correct Answer: 2

Dihydroorotate dehydrogenase contains

1. 4 flavins and 4 atoms of iron per molecule
2. 2 flavins and 4 atoms of iron per molecule
3. 2 flavins and 2 atoms of iron per molecule
4. 4 flavins and 2 atoms of iron per molecule

✅ Correct Answer: 1

E.coli ACP has its molecular weight as around

1. 9000
2. 19000
3. 39000
4. 90,000

✅ Correct Answer: 1

The vitamin riboflavin is part of the __________ molecule.

1. ferredoxin
2. FAD
3. pyridoxal phosphat
4. pyrophosphate

✅ Correct Answer: 2

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

1. antioxidants
2. reducing agent
3. oxidizing agent
4. all of these

✅ Correct Answer: 1

Biotin occurs mainly in combined forms bound to protein through

1. ε-N-lysine moiety
2. ε-S-lysine moiety
3. ε-N-biotinyl-L-lysine
4. ε-N-lipoyl - L-lysine

✅ Correct Answer: 1

Lipoic acid is a co-factor of the

1. pyruvic dehydrogenase
2. α-ketoglutaric dehydrogenase
3. both (a) and (b)
4. di-hydroorotate dehydrogenase

✅ Correct Answer: 3

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

1. plants
2. animal
3. plants and animals both
4. none of these

✅ Correct Answer: 1

Vitamin-D deficiency can cause

1. rickets
2. pernicious anemia
3. cataract
4. beri-beri

✅ Correct Answer: 1

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

1. antioxidants
2. reducing agent
3. oxidizing agent
4. all of these

✅ Correct Answer: 1

Biotin occurs mainly in combined forms bound to protein through

1. ε-N-lysine moiety
2. ε-S-lysine moiety
3. ε-N-biotinyl-L-lysine
4. ε-N-lipoyl - L-lysine

✅ Correct Answer: 1

Lipoic acid is a co-factor of the

1. pyruvic dehydrogenase
2. α-ketoglutaric dehydrogenase
3. both (a) and (b)
4. di-hydroorotate dehydrogenase

✅ Correct Answer: 3

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

1. plants
2. animal
3. plants and animals both
4. none of these

✅ Correct Answer: 1

A deficiency of Vitamin K results in a decreased level of

1. prothrombin
2. thrombin
3. fibrin
4. fibrinogen

✅ Correct Answer: 1

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

1. colorless on reduction with Zn in acid and regained its color on re-oxidation
2. colorless on oxidation and regained its color on reduction with Zn in acid
3. more deep in color on reduction with Zn in acid and regained its color on re-oxidation
4. more deep in color on oxidation and regained its color on reduction with Zn in acid

✅ Correct Answer: 1

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

1. Pyridoxal
2. Pyridoxine
3. Pyridoxamine
4. All of these

✅ Correct Answer: 4

What metal ion is specifically bound by vitamin B12?

1. Cobalt
2. Copper
3. Zinc
4. Iron

✅ Correct Answer: 1

A fat-soluble vitamin that regulates blood clotting is

1. vitamin A
2. vitamin K
3. vitamin C
4. niacin

✅ Correct Answer: 2

Which of these is a vitamin A precursor?

1. Cobalamin
2. Pyridoxine
3. Beta-Carotene
4. Thiamine

✅ Correct Answer: 3

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

1. heme-protein
2. nonheme type
3. both (a) and (b)
4. flavin moiety

✅ Correct Answer: 1

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

1. four isoprene units
2. six isoprene units
3. nine isoprene units
4. four isoprene units

✅ Correct Answer: 1

Which of these molecules is vitamin H?

1. Biotin
2. Carnitine
3. Folic acid
4. None of these

✅ Correct Answer: 1

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

1. stabilize the semiquinone
2. de-stabilize the semiquinone
3. form chelation
4. all of these

✅ Correct Answer: 1

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

1. both ends by one disulfide bond
2. either end via two disulfide bonds
3. either end via a single disulfide bond
4. both ends by two disulfide bonds

✅ Correct Answer: 4

A deficiency of niacin causes

1. pellagra
2. scurvy
3. cataract
4. anemia

✅ Correct Answer: 1

Selenium is an essential component of the enzyme glutathione peroxidase which

1. scavenges toxic hydoperoxycompounds in tissues
2. reduces toxic hydoperoxycompounds in tissues
3. oxidizes toxic hydoperoxycompounds in tissues
4. none of the above

✅ Correct Answer: 1

Who discovered vitamin C (ascorbic acid)?

1. Paul Berg
2. Linus Pauling
3. Albert Szent-Gyorgyi
4. Kerry Mull is

✅ Correct Answer: 3

Molar absorbtivities of compounds exhibiting charge transfer absorption are

1. small
2. moderate
3. large
4. none of these

✅ Correct Answer: 3