AP BIOLOGY

Detailed explanation-1: -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. Attached to each sugar is one of four bases–adenine (A), cytosine (C), guanine (G), or thymine (T).

Detailed explanation-2: -DNA is made of two linked strands that wind around each other to resemble a twisted ladder-a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.

Detailed explanation-3: -The backbone of a DNA molecule consists of the phosphate groups and the deoxyribose sugars, whereas the base region of the DNA molecule consists of the nitrogenous bases; therefore, the backbone of DNA is made up of phosphate groups and pentose sugars. Adenine is part of the base region of the molecule.

Detailed explanation-4: -The sugars and phosphates are referred to as the “backbone” because they provide the structure and support of the molecule, keeping these bases in the correct order. How can an enormous amount of DNA fit inside one cell? The chromosomes that are found in prokaryotes are different from those found in eukaryotes.

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. The sugar is the 3’ end, and the phosphate is the 5’ end of each nucleiotide.