CSS - PMS - CCE - PCS - General Science
Vitamins
Raw egg whites consumed in very large amounts can contribute to biotin deficiency because they contain:
A. Avidin
B. Intrinsic factor
C. Trypsin
D. Calcitonin
Correct Answer: A
A is correct because avidin binds biotin strongly and reduces its intestinal absorption; cooking denatures avidin.
CSS - PMS - CCE - PCS - General Science
Vitamins
Biotin acts mainly as a cofactor for enzymes that perform:
A. Carboxylation reactions
B. Gamma-carboxylation of clotting factors
C. DNA methylation only
D. Phototransduction
Correct Answer: A
A is correct because biotin is covalently attached to carboxylases involved in fatty-acid synthesis, gluconeogenesis and amino-acid metabolism.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin B7 is better known as:
A. Biotin
B. Niacin
C. Folate
D. Thiamine
Correct Answer: A
A is correct. Vitamin B7 is biotin.
CSS - PMS - CCE - PCS - General Science
Vitamins
Excessive long-term vitamin B6 supplementation can itself cause:
A. Sensory neuropathy
B. Rickets
C. Pellagra
D. Bleeding from vitamin K deficiency
Correct Answer: A
A is correct because chronic high-dose pyridoxine can damage sensory nerves and produce neuropathy.
CSS - PMS - CCE - PCS - General Science
Vitamins
Severe vitamin B6 deficiency may cause:
A. Peripheral neuropathy and microcytic/sideroblastic anemia
B. Scurvy
C. Osteomalacia only
D. Xerophthalmia
Correct Answer: A
A is correct because B6 deficiency can impair heme synthesis and neurotransmitter metabolism, causing neuropathy, dermatitis and sideroblastic anemia.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which drug is well known to increase the risk of vitamin B6 deficiency and is often given with pyridoxine?
A. Isoniazid
B. Paracetamol
C. Amoxicillin
D. Metformin only
Correct Answer: A
A is correct because isoniazid can cause functional pyridoxine deficiency and peripheral neuropathy; pyridoxine is often co-prescribed in at-risk patients.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin B6 is especially important in:
A. Amino acid metabolism
B. Calcium deposition only
C. Iodine absorption
D. Vitamin D synthesis in skin
Correct Answer: A
A is correct because PLP-dependent enzymes are central to transamination, decarboxylation and other amino-acid reactions.
CSS - PMS - CCE - PCS - General Science
Vitamins
The principal active coenzyme form of vitamin B6 is:
A. Pyridoxal phosphate (PLP)
B. FAD
C. THF
D. TPP
Correct Answer: A
A is correct because pyridoxal phosphate is the main active coenzyme form of vitamin B6.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin B6 refers to compounds including:
A. Pyridoxine, pyridoxal and pyridoxamine
B. Retinol and retinal
C. Calciferol and calcitriol
D. Tocopherol and tocotrienol only
Correct Answer: A
A is correct because vitamin B6 includes pyridoxine, pyridoxal and pyridoxamine derivatives.
CSS - PMS - CCE - PCS - General Science
Vitamins
Deficiency of pantothenic acid is considered rare mainly because it is:
A. Widely distributed in foods
B. Made only by sunlight
C. Stored for decades in bone
D. Not required by humans
Correct Answer: A
A is correct because pantothenic acid is widely present in foods, making isolated deficiency uncommon.
CSS - PMS - CCE - PCS - General Science
Vitamins
Pantothenic acid is an essential component of:
A. Coenzyme A
B. Rhodopsin
C. Thyroxine
D. Hemoglobin heme only
Correct Answer: A
A is correct because pantothenic acid forms part of coenzyme A and acyl carrier protein, which are central to acyl-group metabolism.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin B5 is known as:
A. Pantothenic acid
B. Pyridoxine
C. Folate
D. Cobalamin
Correct Answer: A
A is correct. Vitamin B5 is pantothenic acid.
CSS - PMS - CCE - PCS - General Science
Vitamins
High-dose nicotinic acid may cause which characteristic adverse effect?
A. Flushing
B. Night blindness
C. Rickets
D. Scurvy
Correct Answer: A
A is correct because pharmacologic niacin commonly causes prostaglandin-mediated flushing; it may also affect liver function and glucose/uric acid metabolism.
CSS - PMS - CCE - PCS - General Science
Vitamins
The classic '3 Ds' of pellagra are:
A. Dermatitis, diarrhea and dementia
B. Deafness, diplopia and dysphagia
C. Dermatitis, diabetes and dyspnea
D. Diarrhea, dehydration and deafness
Correct Answer: A
A is correct. Pellagra classically presents with dermatitis, diarrhea and dementia; untreated severe disease may progress to death.
CSS - PMS - CCE - PCS - General Science
Vitamins
Pellagra is caused chiefly by deficiency of:
A. Niacin
B. Vitamin K
C. Vitamin D
D. Vitamin E
Correct Answer: A
A is correct because niacin deficiency causes pellagra.
CSS - PMS - CCE - PCS - General Science
Vitamins
The amino acid that can be converted in the body to niacin is:
A. Tryptophan
B. Glycine
C. Alanine
D. Aspartate
Correct Answer: A
A is correct because tryptophan can be converted to niacin, although the conversion is limited and requires other nutrients.
CSS - PMS - CCE - PCS - General Science
Vitamins
Niacin is a precursor of:
A. NAD and NADP
B. FAD and FMN
C. Coenzyme A only
D. Thiamine pyrophosphate
Correct Answer: A
A is correct because niacin forms the redox coenzymes NAD+ and NADP+.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin B3 is commonly known as:
A. Niacin
B. Biotin
C. Folate
D. Cobalamin
Correct Answer: A
A is correct. Vitamin B3 refers to niacin, including nicotinic acid and nicotinamide.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin is unusually sensitive to light, making milk storage away from strong light desirable?
A. Riboflavin
B. Vitamin K
C. Vitamin B12
D. Vitamin A
Correct Answer: A
A is correct because riboflavin is light sensitive and can degrade when exposed to light.
CSS - PMS - CCE - PCS - General Science
Vitamins
A classic sign of riboflavin deficiency is:
A. Angular cheilitis
B. Rickets
C. Night blindness
D. Bleeding tendency
Correct Answer: A
A is correct because riboflavin deficiency can cause angular stomatitis/cheilitis, glossitis and dermatitis.