Answer: Electron/hydrogen carrier in oxidation-reduction reactions.
- A Electron/hydrogen carrier in oxidation-reduction reactions
- B A phospholipid component of the cell membrane bilayer
- C A high-energy phosphate storage molecule like ATP
- D An enzyme that excises damaged bases from DNA
Correct answer: A. Electron/hydrogen carrier in oxidation-reduction reactions
Explanation: NAD+ (nicotinamide adenine dinucleotide) accepts electrons/hydrogen in metabolic oxidation reactions.
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.