AP BIOLOGY

Detailed explanation-1: -Uracil is the nitrogenous base present only in RNA, but not in DNA. Thymine is in DNA. DNA have thymine, guanine, adenine and cytosine. Thymine is replaced by uracil in RNA.

Detailed explanation-2: -Uracil is present in RNA but not in DNA.

Detailed explanation-3: -RNA consists of four nitrogenous bases: adenine, cytosine, uracil, and guanine. Uracil is a pyrimidine that is structurally similar to the thymine, another pyrimidine that is found in DNA. Like thymine, uracil can base-pair with adenine (Figure 2).

Detailed explanation-4: -Uracil is one of these bases. However, since mRNA is relatively short-lived and any potential faults don’t result in any lasting damage, RNA employs uracil because the instability doesn’t matter as much for RNA. Thymine is also quickly oxidized. The thymine in the nucleus is shielded from oxygen.

Detailed explanation-5: -Uracil (U) is one of the four nucleotide bases in RNA, with the other three being adenine (A), cytosine (C) and guanine (G). In RNA, uracil pairs with adenine. In a DNA molecule, the nucleotide thymine (T) is used in place of uracil.