Question 54:
Another name for Vitamin D3 is:
The correct answer is (D) Cholecalciferol.
Vitamin D3, also known as cholecalciferol, is the form synthesized in human skin from 7-dehydrocholesterol upon UVB exposure or obtained from animal sources like fish oil.
Option Breakdown
(A) Retinol
Retinol is Vitamin A, essential for vision and epithelial health, not related to D3’s calcium regulation role.
(B) Dolichol
Dolichol is a long-chain polyisoprenoid lipid involved in glycoprotein synthesis in the ER, unrelated to vitamins.
(C) Tocopherol
Tocopherol refers to Vitamin E forms, acting as lipid-soluble antioxidants protecting cell membranes.
(D) Cholecalciferol
This is the precise alternative name for Vitamin D3, converted to active calcitriol (1,25-dihydroxyvitamin D3) in liver and kidneys.
Introduction to Vitamin D3 Cholecalciferol
Vitamin D3 cholecalciferol is the animal-derived form critical for bone health via calcium/phosphate absorption. GATE Life Sciences questions test this nomenclature against other fat-soluble vitamins and lipids.
Vitamin Forms and Functions
D3 (cholecalciferol) from skin/sunlight contrasts D2 (ergocalciferol) from plants; both activate to calcitriol. Deficiency causes rickets/osteomalacia.
Unlike retinol (A) or tocopherol (E), D3 uniquely regulates PTH and bone remodeling.
Options Comparison Table
| Option | Compound Type | Vitamin? | Key Role |
|---|---|---|---|
| Retinol | Vitamin A | Yes | Vision, immunity |
| Dolichol | Lipid carrier | No | N-glycosylation |
| Tocopherol | Vitamin E | Yes | Antioxidant |
| Cholecalciferol | Vitamin D3 | Yes | Calcium homeostasis |
Confirms Vitamin D3 cholecalciferol as the match.
Exam Context for Life Sciences
Links to prior nutrition (trans fats) and liver queries (albumin synthesis site for D activation); master fat-soluble vitamin names for PYQs.
