Vitamin A

Question 1

Deficiency of vitamin A can cause

Answer 1

night blindness(nyctalopia), xerophtalmia, gingivitis, periodontitis, keratinization of epithelial cells.

Question 2

Form of vitamin A that is responsible for transcription or gene activation is

Answer 2

Retinoic acid

Question 3

Acne and psoriasis can be treated with

Answer 3

Retinoic acid

Question 4

form of vitamin A that is transported in blood is

Answer 4

Retinol

Question 5

Vitamin A metabolism

Answer 5

Beta-carotene -> Retinal -> Retinol -> Retinyl Ester (in intestinal cells, carried by chylomicron to lymph vessels) -> All-trans retinol -> Retinyl palmitate ( Retinol stored in liver as retinyl ester) -> Retinol (carried with RBP in blood) -> Retina or Target Tissues

Question 6

Vitamin A Metabolism in Retina

Answer 6

Retinol -> All-trans-retinol -> All-trans retinyl ester -> 11-cis-retinol -> 11-cis-retinal -> Rhodopsin -> all-trans retinal -> All-trans retinol

Question 7

Vitamin A metabolism in Target Tissues

Answer 7

Retinol -> Retinoic acid (gene activation with RAR, retinoic acid receptor)

Question 8

Irreversible oxidation of retinol is

Answer 8

Retinoic acid