Answer: Right-handed double helix, 10 base pairs per turn, major and minor grooves.
- A Right-handed double helix, 10 base pairs per turn, major and minor grooves
- B Left-handed double helix with 12 base pairs per turn (Z-DNA form) in many documented cases
- C A single-stranded structure lacking complementary base pairing according to conventional understanding
- D A right-handed helix with 14 base pairs per turn in routine practice
Correct answer: A. Right-handed double helix, 10 base pairs per turn, major and minor grooves
Explanation: The B-form (Watson-Crick form) of DNA is a right-handed helix with 10 base pairs per turn and distinct major and minor grooves.
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.