AP BIOLOGY

Detailed explanation-1: -Replication relies on complementary base pairing, that is the principle explained by Chargaff’s rules: adenine (A) always bonds with thymine (T) and cytosine (C) always bonds with guanine (G).

Detailed explanation-2: -So the DNA replication is possible only by the complementary base pairing of the nucleotides Adenine with thymine and guanine with cytosine. These nucleotides are bound to each other with the help of hydrogen bonds and the phosphate backbone is meant to provide support to the DNA molecule.

Detailed explanation-3: -Answer and Explanation: The correct statement is a because DNA complementary base pairing occurs when C binds to G and A binds to T. Statement b is incorrect because adenine base pairs with thymine, not guanine, and cytosine base pairs with guanine, not thymine.

Detailed explanation-4: -A DNA molecule replicates to form two identical copies of itself. During the cell cycle, replication occurs at ‘S’ phase. DNA replication is a semiconservative process, in the newly formed double-stranded DNA, one strand of original DNA is retained, which acts as a template for the formation of another strand.

Detailed explanation-5: -What is the complementary base pairing rule for DNA? Complementary base pairs refer to the nitrogenous bases adenine, thymine, cytosine, and guanine. in a double strand of DNA, adenine will always pair with its complement thymine and cytosine will always pair with its complement guanine.