AP BIOLOGY

Detailed explanation-1: -Key Points. The two main types of nucleic acids are DNA and RNA. Both DNA and RNA are made from nucleotides, each containing a five-carbon sugar backbone, a phosphate group, and a nitrogen base.

Detailed explanation-2: -Nucleotide A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T).

Detailed explanation-3: -Both DNA and RNA are built with a sugar backbone, but whereas the sugar in DNA is called deoxyribose (left in image), the sugar in RNA is called simply ribose (right in image).

Detailed explanation-4: -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-5: -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.