BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Definition. 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.

Detailed explanation-2: -Uracil is only found in RNA, and is absent from DNA. During DNA replication and synthesis, nucleotides align so that the nitrogenous bases are correctly paired. The bases bind to one other via hydrogen bonding to secure the nucleotide to the template strand.

Detailed explanation-3: -Uracil is present in RNA but not in DNA.

Detailed explanation-4: -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-5: -Three of the four nitrogenous bases that make up RNA-adenine (A), cytosine (C), and guanine (G)-are also found in DNA. In RNA, however, a base called uracil (U) replaces thymine (T) as the complementary nucleotide to adenine (Figure 3).