Edexcel IGCSE Biology Section 2c - Biological Molecules

amino acid

the basic unit of a protein

carbohydrate

a molecule formed of carbon, hydrogen and oxygen that is used as a source of chemical energy in living organisms

lipid

fats and oils, made of fatty acids and glycerol

fatty acid

a basic unit of lipids

glycerol

a basic unit of lipids

proteins

large molecules, made of amino acids which have unique shapes which often determine their properties e.g. enzymes, collagen

simple sugar

a small carbohydrate molecule such as glucose, that when joined with other simple sugars can form large carbohydrate molecules such as starch

catalyst

a substance that helps speed up a reaction without being used up in the reaction

enzyme

a biological catalyst which speeds up metabolic reactions that happen inside living organisms

specific

only works with one (or a few) substances

substrate

the substance(s) that is either broken down or joined together in an enzyme controlled reaction

active site

part of an enzyme with a very specific 3D shape which matches the shape of the substrate(s)