AP BIOLOGY

Detailed explanation-1: -Under normal circumstances, the nitrogen-containing bases adenine (A) and thymine (T) pair together, and cytosine (C) and guanine (G) pair together. The binding of these base pairs forms the structure of DNA .

Detailed explanation-2: -Two nitrogen-containing bases (or nucleotides) that pair together to form the structure of DNA. The four bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). These bases form specific pairs (A with T, and G with C).

Detailed explanation-3: -A unit of two bases in a molecule of DNA or RNA. In DNA, adenine always pairs with thymine (A-T), and guanine always pairs with cytosine (G-C). RNA is the same, except that adenine always pairs with uracil (A-U).

Detailed explanation-4: -Adenine always pairs with thymine through two hydrogen bonds in DNA. Similarly, adenine pairs with uracil through two hydrogen bonds in RNA and guanine always pairs with cytosine through three hydrogen bonds in both the nucleic acids.

Detailed explanation-5: -Complementary Sequence: Since DNA has two strands, every DNA sequence has a complementary sequence running parallel. In the complementary sequence, Adenine (A) is always paired with Thymine (T), and Cytosine (C) is always paired with Guanine (G).