AP BIOLOGY

Detailed explanation-1: -Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs.

Detailed explanation-2: -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-3: -These hydrogen bonds are what hold the two strands of DNA together to form the double helix. Guanine and cytosine form three hydrogen bonds, while adenine and thymine form two. Therefore, the type of bond that forms between complementary base pairs in DNA is a hydrogen bond.

Detailed explanation-4: -Double-stranded DNA consists of two polynucleotides that are arranged such that the nitrogenous bases within one polynucleotide are attached to the nitrogenous bases within another polynucleotide by way of special chemical bonds called hydrogen bonds.

Detailed explanation-5: -A DNA molecule consists of two polynucleotide strands that form a double helix. The strands are held together by hydrogen bonds between the nitrogen-containing bases.