AP BIOLOGY

Detailed explanation-1: -During elongation, an enzyme called DNA polymerase adds DNA nucleotides to the 3′ end of the template. Because DNA polymerase can only add new nucleotides at the end of a backbone, a primer sequence, which provides this starting point, is added with complementary RNA nucleotides.

Detailed explanation-2: -DNA is always synthesized in the 5’-to-3’ direction, meaning that nucleotides are added only to the 3’ end of the growing strand. As shown in Figure 2, the 5’-phosphate group of the new nucleotide binds to the 3’-OH group of the last nucleotide of the growing strand.

Detailed explanation-3: -A DNA strand with the fifth carbon within the sugar ring at its terminus is said to have a five prime end. On the 3′ carbon of its terminal sugar, the 3′ end has a free hydroxyl group. The three prime ends of a molecule is the end that ends in a 3′ phosphate group.

Detailed explanation-4: -The addition of a deoxyribonucleotide to the 3′ end of a polynucleotide chain (the primer strand) is the fundamental reaction by which DNA is synthesized.

Detailed explanation-5: -DNA replication goes in the 5’ to 3’ direction because DNA polymerase acts on the 3’-OH of the existing strand for adding free nucleotides.