Answer: Vitamin D.
- A Vitamin D
- B Vitamin C
- C Vitamin A
- D Vitamin B12
Correct answer: A. Vitamin D
Explanation: Vitamin D is synthesised in the skin upon UV exposure from sunlight.
Two amino acids join via a condensation reaction: the carboxyl -OH of one and an amine -H of the other are eliminated as water, leaving a peptide bond (-CO-NH-) linking them into a dipeptide; repeating this builds a full protein chain.
Concept context
The chemistry of life: carbohydrates, proteins, lipids, nucleic acids, enzymes, and vitamins. Understand their structures, classification, and biological functions. Highly relevant for NEET and Class 12 board exams.