BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Unlike DNA, however, RNA is most often single-stranded. An RNA molecule has a backbone made of alternating phosphate groups and the sugar ribose, rather than the deoxyribose found in DNA. Attached to each sugar is one of four bases: adenine (A), uracil (U), cytosine (C) or guanine (G).

Detailed explanation-2: -Which molecule is always single-stranded? RNA is always single-stranded and is often referred to as single-stranded ribonucleic acid. This can be seen in Figure 1 below. However, DNA can be either double-stranded or a single strand of DNA (ssDNA).

Detailed explanation-3: -Single-stranded RNA (ssRNA) is the simplest form of genetic molecule and constitutes the genome in some viruses and presumably in primitive life-forms. However, an innate and unsolved problem regarding the ssRNA genome is formation of inactive double-stranded RNA (dsRNA) during replication.

Detailed explanation-4: -Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA, RNA is found in nature as a single strand folded onto itself, rather than a paired double strand.