ABSTRACT
Monomers combine to form biopolymers. Polysaccharides are composed of carbohydrate units joined by a covalent bond. Proteins consist of (a) self-folding chain(s) that are made up of 20 amino acids, which are joined by a covalent bond. Lipids contain a hydrophilic part, mainly glycerol, and hydrophobic long-chain fatty acids. DNA and RNA are the chains of nucleotides. Each nucleotide contains a sugar (ribose in RNA and deoxyribose in DNA), phosphate, and a nitrogen-containing base: adenine (A), guanine (G), cytosine (C), and thymine (T, in DNA only), and uracil (U, in RNA only). DNA consists of two sugar-phosphate backbones, which are held together by the hydrogen bonds between the complementary bases (A-T and G-C) on two strands. RNA molecule is single-stranded. RNA occurs as messenger, transfer, ribosomal RNAs and regulatory microRNAs. A tutorial with solutions and a quiz bank are added to this chapter.
