CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin deficiency may produce glossitis, cheilosis and a magenta tongue?
A. Riboflavin (B2)
B. Vitamin D
C. Vitamin K
D. Vitamin E
Correct Answer: A
A is correct because riboflavin deficiency can produce angular cheilitis, stomatitis, glossitis and a magenta tongue.
CSS - PMS - CCE - PCS - General Science
Vitamins
Transketolase activity depends on:
A. Thiamine pyrophosphate
B. Vitamin K hydroquinone
C. Retinoic acid
D. Alpha-tocopherol
Correct Answer: A
A is correct because transketolase in the pentose phosphate pathway is a TPP-dependent enzyme.
CSS - PMS - CCE - PCS - General Science
Vitamins
Pyruvate dehydrogenase requires which vitamin-derived coenzyme among its cofactors?
A. Thiamine pyrophosphate from B1
B. Retinal from vitamin A
C. Phylloquinone from vitamin K
D. Ascorbate from vitamin C only
Correct Answer: A
A is correct because pyruvate dehydrogenase uses TPP derived from thiamine, along with other cofactors.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which B vitamin-derived coenzyme is used by aminotransferases?
A. Pyridoxal phosphate from B6
B. FAD from B2 only
C. TPP from B1 only
D. THF from B9 only
Correct Answer: A
A is correct because aminotransferases require pyridoxal phosphate, the active form of vitamin B6.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which B vitamin is required for conversion of methylmalonyl-CoA to succinyl-CoA?
A. B12
B. B2
C. B7
D. B9
Correct Answer: A
A is correct because adenosylcobalamin, a B12 coenzyme, is required by methylmalonyl-CoA mutase.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which B vitamin forms the coenzyme tetrahydrofolate, which transfers one-carbon units?
A. B9
B. B1
C. B2
D. B5
Correct Answer: A
A is correct because folate (B9) is reduced to tetrahydrofolate derivatives used in one-carbon metabolism.
CSS - PMS - CCE - PCS - General Science
Vitamins
A deficiency caused by lack of one nutrient despite adequate total calories is best described as:
A. Specific micronutrient deficiency
B. Protein-energy excess
C. Vitamin toxicity
D. Hypervitaminosis
Correct Answer: A
A is correct because vitamin deficiencies can occur despite sufficient calories if diet quality, absorption or metabolism is inadequate.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin deficiency can prolong prothrombin time (PT/INR)?
A. Vitamin K
B. Vitamin C
C. Vitamin B1
D. Vitamin E only
Correct Answer: A
A is correct because vitamin K deficiency decreases functional clotting factors II, VII, IX and X, often prolonging PT/INR.
CSS - PMS - CCE - PCS - General Science
Vitamins
Broad-spectrum antibiotic therapy can increase risk of deficiency of which vitamin by reducing intestinal bacterial production?
A. Vitamin K
B. Vitamin C
C. Vitamin A
D. Vitamin D
Correct Answer: A
A is correct because prolonged broad-spectrum antibiotics may reduce vitamin K-producing gut flora, particularly in people with poor intake or other risks.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin is synthesized partly by intestinal bacteria but dietary intake remains important?
A. Vitamin K
B. Vitamin C
C. Vitamin A
D. Vitamin D only
Correct Answer: A
A is correct because gut bacteria produce menaquinones (vitamin K2), but dietary vitamin K—especially K1—remains important.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin has tocopherols and tocotrienols as its major chemical families?
A. Vitamin E
B. Vitamin A
C. Vitamin D
D. Vitamin K
Correct Answer: A
A is correct because vitamin E includes tocopherols and tocotrienols.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin is most directly involved in dark adaptation of the eye?
A. Vitamin A
B. Vitamin K
C. Vitamin B5
D. Vitamin E
Correct Answer: A
A is correct because retinal, derived from vitamin A, is a component of rhodopsin required for low-light vision.
CSS - PMS - CCE - PCS - General Science
Vitamins
Retinoic acid mainly exerts its effects by binding to:
A. Nuclear retinoid receptors
B. Cell-surface insulin receptors
C. Ribosomes
D. Hemoglobin
Correct Answer: A
A is correct because retinoic acid regulates gene expression through nuclear retinoic acid receptors.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin can function as a hormone-like regulator of gene expression through a nuclear receptor?
A. Vitamin D
B. Vitamin C
C. Vitamin B1
D. Biotin only
Correct Answer: A
A is correct because calcitriol binds the vitamin D receptor, a nuclear receptor that regulates transcription.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which water-soluble vitamin has unusually substantial body stores lasting years?
A. Vitamin B12
B. Vitamin C
C. Vitamin B1
D. Vitamin B2
Correct Answer: A
A is correct because vitamin B12 is stored extensively in the liver, unlike most water-soluble vitamins.
CSS - PMS - CCE - PCS - General Science
Vitamins
Compared with fat-soluble vitamins, most water-soluble vitamins are:
A. Stored in smaller amounts and excess is more readily excreted
B. Always stored for decades
C. Never excreted in urine
D. Only absorbed with bile salts
Correct Answer: A
A is correct because most water-soluble vitamins have limited body stores and excess is commonly excreted in urine; B12 is a notable storage exception.
CSS - PMS - CCE - PCS - General Science
Vitamins
A patient with severe fat malabsorption is particularly at risk of deficiency of:
A. Vitamins A, D, E and K
B. Only vitamin C
C. Only vitamin B1
D. Only vitamin B12
Correct Answer: A
A is correct because fat malabsorption reduces absorption of all fat-soluble vitamins A, D, E and K.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which statement about fat-soluble vitamins is generally correct?
A. They are absorbed with dietary fat and can accumulate in body stores
B. They are all rapidly excreted in urine
C. They cannot be stored at all
D. They include all B vitamins
Correct Answer: A
A is correct because A, D, E and K depend on fat absorption and can be stored to varying degrees, increasing toxicity risk when consumed excessively.
CSS - PMS - CCE - PCS - General Science
Vitamins
Very high vitamin C intake may increase the risk of which problem in susceptible individuals?
A. Oxalate kidney stones
B. Rickets
C. Pellagra
D. Vitamin K deficiency bleeding
Correct Answer: A
A is correct because high-dose vitamin C can increase urinary oxalate and may contribute to stones in susceptible people.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin C is easily lost from foods by:
A. Prolonged heating and exposure to water/air
B. Freezing for a short time only
C. Keeping food whole
D. Eating food fresh
Correct Answer: A
A is correct because vitamin C is water soluble and heat/oxidation sensitive, so prolonged cooking and discarding cooking water can reduce content.