AP BIOLOGY

Detailed explanation-1: -A phosphate backbone is the portion of the DNA double helix that provides structural support to the molecule. DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.

Detailed explanation-2: -Covalent bonds occur within each linear strand and strongly bond the bases, sugars, and phosphate groups (both within each component and between components). Hydrogen bonds occur between the two strands and involve a base from one strand with a base from the second in complementary pairing.

Detailed explanation-3: -Molecules called nucleotides, on opposite strands of the DNA double helix, that form chemical bonds with one another. These chemical bonds act like rungs in a ladder and help hold the two strands of DNA together.

Detailed explanation-4: -This type of bond is called a glycosidic bond. The phosphate group forms a bond with the deoxyribose sugar through an ester bond between one of its negatively charged oxygen groups and the 5’-OH of the sugar ().

Detailed explanation-5: -DNA and RNA are composed of nucleotides that are linked to one another in a chain by chemical bonds, called ester bonds, between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide.