Biomolecules

Biomolecules are the organic molecules that build and run living cells - carbohydrates, proteins, enzymes, vitamins, nucleic acids and hormones. This chapter, worth a reliable 6-9 Board marks and 3-5 JEE/NEET questions a year, connects the organic chemistry of the earlier chapters to the chemistry of life. We study carbohydrates - their classification as mono-, di- and polysaccharides and as reducing/non-reducing sugars, the open-chain and cyclic (pyranose/furanose) structures of glucose and fructose, anomers and mutarotation, the glycosidic linkage, and the disaccharides (sucrose, maltose, lactose) and polysaccharides (starch - amylose and amylopectin, cellulose, glycogen). We then cover proteins - alpha-amino acids and the zwitterion, the peptide bond, the four levels of protein structure (primary, secondary - the alpha-helix and beta-pleated sheet, tertiary and quaternary) and denaturation; enzymes as biological catalysts and their specificity; vitamins - their classification into fat-soluble (A, D, E, K) and water-soluble (B group and C), sources and deficiency diseases; nucleic acids - DNA and RNA, nucleosides and nucleotides, the double-helix structure, complementary base pairing and the biological functions of replication and protein synthesis; and a brief look at hormones. Every classification, structure, linkage and exam-favourite distinction is covered.