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: -In RNA, uracil binds to adenine via two hydrogen bonds.

Detailed explanation-3: -Answer and Explanation: RNA uses uracil instead of thymine because RNA is already short-lived (compared to DNA) and errors don’t lead to long-lasting damage. Most importantly, uracil is less stable than thymine thereby making it easier to break down, as it is essentially a demethylated version of thymine.

Detailed explanation-4: -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).

Detailed explanation-5: -RNA uses the base uracil (U) rather than thymine (T) The only difference between the two molecules is the presence or absence of the CH3 group. Uracil can form exactly the same hydrogen bonds with adenine as thymine can-the shape of the two molecules is exactly the same where it matters.