MDCAT Chemistry · Chemistry · Macromolecules. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
Living things build large molecules from small units. Proteins are chains of α-amino acids joined by peptide (amide) links, –CO–NH–. Carbohydrates are built from sugar units, and nucleic acids from nucleotides. Fats and oils are esters of glycerol with three fatty acids.
Enzymes are proteins that act as catalysts. Each one fits its own substrate at an active site, so it is very specific. It works best at one temperature and one pH, and heat destroys its shape (denaturation).
Proteins are grouped by shape, as fibrous or globular, and by the job they do, such as structure, transport, hormones or defence.
Students say heating an enzyme breaks its peptide bonds. Denaturation breaks only the weak bonds that hold the folded shape; the amino acid sequence (primary structure) is unchanged, and only hydrolysis breaks peptide bonds.
Answer: Iodine number = 86 (to 2 significant figures)
Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.