Metabolism: Cell level systems: Biology: GCSE (9:1)

Metabolism

The sum of all the reactions in a cell or the body

Metabolism includes

The synthesis of new molecules, the breakdown of existing molecules and the process of respiration

Energy transferred by cellular respiration

Is used by organisms for the continual enzyme-controlled processes of metabolism

Enzymes and metabolism

Enzymes regulate most cellular reactions and are essential for the synthesis and breakdown of molecules

Conversion of glucose to complex carbohydrates

Glucose can be converted into starch, glycogen and cellulose

Formation of lipid molecules

One molecule of glycerol joins with three fatty acids

Amino acid production

Glucose and nitrate ions form amino acids which are used to make proteins

Protein synthesis

Amino acids join together in specific arrangements to form proteins

Urea excretion

Excess proteins are broken down to form urea for excretion

Digestion

Requires energy from respiration to break down large insoluble molecules into smaller soluble molecules

Carbohydrates

Provide energy for chemical reactions and can break down into sugars

Proteins

The building blocks of cells and tissues that can break down into amino acids

Lipids

An energy store of fats and oils that can break down into glycerol and fatty acids

Monomer

A simple compound whose molecules can join together to form polymers, such as glucose which can be used to make up a complex carbohydrate called glycogen

Polymer

A long molecule consisting of many similar or identical monomers linked together, such as glycogen which is made up of many glucose molecules