AP BIOLOGY

Detailed explanation-1: -The structure of DNA is a double helix. In other words, it is a double stranded molecule that twists like a spiral staircase. The outsides of the molecule, the railings of the staircase, are made of deoxyribose sugars alternating with phosphates. This part of the molecule is sometimes called the “backbone ".

Detailed explanation-2: -Double Helix Double helix, as related to genomics, is a term used to describe the physical structure of DNA. A DNA molecule is made up of two linked strands that wind around each other to resemble a twisted ladder in a helix-like shape.

Detailed explanation-3: -The sides of the ladder are made of alternating sugar and phosphate molecules. The sugar is deoxyribose. The rungs of the ladder are pairs of 4 types of nitrogen bases. Two of the bases are purines-adenine and guanine.

Detailed explanation-4: -A sugar-phosphate backbone (alternating grey-dark grey) joins together nucleotides in a DNA sequence. The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. This backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

Detailed explanation-5: -A DNA ladder is a solution of DNA molecules of different lengths used in agarose or acrylamide gel electrophoresis. It is applied as a reference to estimate the size of unknown DNA molecules that were separated based on their mobility in an electrical field through the gel.