60,000+ students trusted us with their dreams. Take the first step today!
One app for all your study abroad needs
Answer: The functionally active form of Vitamin D is Calcitriol, also known scientifically as 1,25-dihydroxyvitamin D3. This is the most biologically active form of Vitamin D and is responsible for performing important functions in the human body, especially regulating calcium and phosphorus levels in the blood. It helps in the absorption of calcium from the intestines, promotes bone strength, and supports the immune system. Calcitriol is produced in the kidneys from calcidiol (25-hydroxyvitamin D), which is itself produced from Vitamin D3 in the liver. So, calcitriol is the final active form that actually works in the body. Thus, the correct answer is option (D) Calcitriol.
Complete Answer:
Let’s now understand why the other options are incorrect:
A. Dehydrocholesterol (7-dehydrocholesterol) is not the active form of Vitamin D. It is a precursor (starting compound) that is found in the skin. When the skin is exposed to sunlight, specifically UVB rays, this substance is converted into cholecalciferol (Vitamin D3). Although it is essential in the early step of Vitamin D synthesis, it has no active role in the body until it is transformed.
B. Cholecalciferol (Vitamin D3) is also not the active form. It is made in the skin or obtained from animal-based foods such as fatty fish, egg yolks, and fortified milk. But in the body, it must first go to the liver, where it becomes calcidiol (25-hydroxyvitamin D), and then to the kidneys, where it becomes calcitriol. So, cholecalciferol is only a prohormone, and it needs conversion to become active.
C. Ergocalciferol (Vitamin D2) is a plant-derived form of Vitamin D, usually obtained from fungi and some fortified foods. Like Vitamin D3, it also needs to be converted by the liver and kidneys to become calcitriol. Hence, it is not functionally active by itself. In fact, some studies suggest that Vitamin D2 may be less effective than Vitamin D3 in maintaining vitamin D levels in the body.
D. Calcitriol is the correct and functionally active form of Vitamin D. It is made in the kidneys and works by increasing calcium and phosphate absorption from the intestines, supporting healthy bone growth and mineralization. It also helps regulate immune responses and other body functions.
Hence, the correct option for ‘Functionally active form of vitamin D is’ is option D.
Common Chemistry Doubts:
