Summary EDEXCEL: AS BIOLOGY REVISION NOTES

EDEXCEL: AS BIOLOGY REVISION NOTES: UNIT 1 Metabolism Metabolism is a term to describe all reaction which is taking place within a cell and is separated into two types which are • anabolic = compounds being built up • catabolic = compounds being broken down Water The water molecule is a molecule which is made up from 2 hydrogen atoms and 1 oxygen atoms. It is bounded by 2 covalent bonds and has is polar. The reason why water molecules are important for living organisms are because : 1. They are important solvents since they are polar 2. Important coolants for excessive metabolic reactions 3. Important for insulation since they have high specific heat capacities 4. It is a very good mechanism for transport since they are highly cohesive 5. Important reagents for chemical reactions ( such as hydrolysis and photosynthesis Carbohydrates Separated into 3 types which are monosaccharides, disaccharides and polysaccharides Monosaccharides • they are three main types of monosaccharides which you have to know in this level which are Pentoses - Such as ribose (with formula C5H10O5) and fructose Hexose - Such as alpha and beta glucoses • All members of monosaccharides are reducing since they have the aldehyde groups, therefore they will cause a brick red persipitate to form when tested with benedict`s solution