NEET BIOLOGY

Detailed explanation-1: -The two polynucleotide chains are antiparallel in DNA. This means that one of them runs from the 5’-3’ direction and the other one runs in the 3’-5’ direction.

Detailed explanation-2: -They run in opposite directions but remain parallel. In other words, the two polynucleotide chains are antiparallel to each other.

Detailed explanation-3: -The two polynucleotide strands run ‘antiparallel’ to each other, with nitrogenous bases projecting inwards. The term ‘antiparallel’ means that the strands run in opposite directions, parallel to one another. The antiparallel strands twist in a complete DNA structure, forming a double helix.

Detailed explanation-4: -Two polynucleotide chains of DNA are wound around the same axis and are held together by complementary base pairing between nitrogenous bases of two strands in the same plane. Adenine of one strand forms two hydrogen bonds with thymine of other strand and guanine forms three hydrogen bonds with cytosine.

Detailed explanation-5: -The strands of a DNA double helix are said to be “antiparallel” because the have the same chemical structure, but are opposite in direction.