CSS - PMS - CCE - PCS - General Science
Vitamins
The main intestinal effect of vitamin D is to increase absorption of:
A. Calcium and phosphate
B. Sodium and chloride only
C. Iron only
D. Vitamin C only
Correct Answer: A
A is correct because vitamin D increases intestinal absorption of calcium and phosphate, supporting bone mineralization.
CSS - PMS - CCE - PCS - General Science
Vitamins
Final activation of vitamin D to calcitriol occurs mainly in the:
A. Kidney
B. Stomach
C. Spleen
D. Colon
Correct Answer: A
A is correct because renal 1-alpha-hydroxylase converts calcidiol to calcitriol.
CSS - PMS - CCE - PCS - General Science
Vitamins
The hormonally active form of vitamin D is:
A. Calcitriol
B. Calcidiol
C. Cholecalciferol
D. Ergocalciferol
Correct Answer: A
A is correct. Calcitriol is 1,25-dihydroxyvitamin D, the active hormone-like form produced mainly in the kidney.
CSS - PMS - CCE - PCS - General Science
Vitamins
The major circulating storage form used to assess vitamin D status is:
A. 25-hydroxyvitamin D (calcidiol)
B. 1,25-dihydroxyvitamin D only
C. 7-dehydrocholesterol
D. Ergosterol
Correct Answer: A
A is correct because serum 25-hydroxyvitamin D is the standard marker of body vitamin D status. Calcitriol is tightly regulated and is not the best routine measure of stores.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin D2 is also called:
A. Ergocalciferol
B. Cholecalciferol
C. Calcidiol
D. Phylloquinone
Correct Answer: A
A is correct. Ergocalciferol is vitamin D2, commonly derived from fungal or plant sterols.
CSS - PMS - CCE - PCS - General Science
Vitamins
The form of vitamin D3 is known as:
A. Cholecalciferol
B. Ergocalciferol
C. Calcitriol
D. Retinal
Correct Answer: A
A is correct. Vitamin D3 is cholecalciferol; vitamin D2 is ergocalciferol.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamin D belongs chemically to a group of compounds called:
A. Secosteroids
B. Amino acids
C. Purines
D. Polysaccharides
Correct Answer: A
A is correct because vitamin D compounds are secosteroids derived from steroid precursors.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which of the following is a rich animal source of preformed vitamin A?
A. Liver
B. White rice
C. Refined sugar
D. Table salt
Correct Answer: A
A is correct because liver is rich in retinol, the preformed animal form of vitamin A.
CSS - PMS - CCE - PCS - General Science
Vitamins
Excessive intake of preformed vitamin A during pregnancy is especially concerning because it may be:
A. Teratogenic
B. Anticoagulant only
C. A cause of scurvy
D. A cause of beriberi
Correct Answer: A
A is correct. High-dose preformed vitamin A and retinoids can cause fetal malformations, so excess intake in pregnancy is avoided.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which vitamin is essential for normal epithelial differentiation and maintenance?
A. Vitamin A
B. Vitamin B12
C. Vitamin C
D. Vitamin K
Correct Answer: A
A is correct because retinoic acid regulates gene transcription involved in epithelial growth and differentiation.
CSS - PMS - CCE - PCS - General Science
Vitamins
Keratomalacia may occur in severe deficiency of:
A. Vitamin A
B. Vitamin B1
C. Vitamin B3
D. Vitamin K
Correct Answer: A
A is correct because severe vitamin A deficiency can soften and damage the cornea, producing keratomalacia.
CSS - PMS - CCE - PCS - General Science
Vitamins
Bitot spots are a clinical sign of deficiency of:
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin B6
Correct Answer: A
A is correct. Bitot spots are foamy conjunctival lesions associated with vitamin A deficiency.
CSS - PMS - CCE - PCS - General Science
Vitamins
Xerophthalmia is classically linked with deficiency of:
A. Vitamin A
B. Vitamin B12
C. Vitamin C
D. Vitamin K
Correct Answer: A
A is correct because vitamin A deficiency causes dryness of the conjunctiva and cornea, which may progress to xerophthalmia and keratomalacia.
CSS - PMS - CCE - PCS - General Science
Vitamins
Night blindness is most strongly associated with deficiency of:
A. Vitamin A
B. Vitamin B2
C. Vitamin E
D. Vitamin K
Correct Answer: A
A is correct because vitamin A is required for retinal formation and dark adaptation. Deficiency can cause night blindness and xerophthalmia.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which pigment in carrots is an important provitamin A carotenoid?
A. Beta-carotene
B. Lycopene
C. Anthocyanin
D. Chlorophyll
Correct Answer: A
A is correct because beta-carotene can be converted to vitamin A in the body. Lycopene is a carotenoid but is not an important provitamin A source.
CSS - PMS - CCE - PCS - General Science
Vitamins
The active aldehyde form of vitamin A involved in vision is:
A. Retinal
B. Retinol
C. Retinoic acid
D. Calcitriol
Correct Answer: A
A is correct. Retinal combines with opsin to form visual pigments such as rhodopsin. Retinol is the alcohol form, retinoic acid regulates gene expression, and calcitriol is active vitamin D.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which fat-soluble vitamin is stored in large amounts in the liver and is essential for vision?
A. Vitamin A
B. Vitamin B1
C. Vitamin C
D. Vitamin B2
Correct Answer: A
A is correct because vitamin A is stored mainly in the liver and is required for the visual cycle, epithelial integrity and immunity.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which group contains only water-soluble vitamins?
A. A, D, E and K
B. B-complex vitamins and vitamin C
C. A, C, E and K
D. D, K and B12 only
Correct Answer: B
B is correct because the B-complex family and vitamin C are water soluble. Vitamins A, D, E and K are fat soluble.
CSS - PMS - CCE - PCS - General Science
Vitamins
Which group contains only fat-soluble vitamins?
A. B1, B2, B6, B12
B. A, D, E, K
C. C, B1, B9, B12
D. A, C, D, B6
Correct Answer: B
B is correct: vitamins A, D, E and K are fat soluble. The B-complex vitamins and vitamin C are water soluble.
CSS - PMS - CCE - PCS - General Science
Vitamins
Vitamins are best described as:
A. Organic micronutrients required in small amounts
B. Inorganic salts needed in kilograms
C. Energy-yielding macronutrients
D. Structural proteins only
Correct Answer: A
A is correct because vitamins are organic micronutrients needed in small quantities for normal metabolism. B describes minerals. C is wrong because vitamins do not themselves supply significant energy. D is wrong because vitamins are not structural proteins.