Metabolism

Metabolism = sum total of all the biochemical reactions taking place in the cells of an organism

Carbohydrates

• Energy storage and supply
• Structure (in some organisms)

Proteins

• Structure
• Transport
• Enzymes
• Antibodies
• Most hormones

Vitamins and Minerals

• Forms part of some larger molecules and take part in some metabolic reactions
• Some act as COENZYMES or enzyme activators

Lipids

• Membanes
• Energy supply
• Thermal insulation
• Protective layers/padding
• Electrical insulation in neurones
• Some hormones

Water

• Takes part in many reactions
• Support in plants
• Solvent/medium for most metabolic reactions
• Transport

Nucleic Acid

• Information molecules, carry out instructions for life

Water (70%)

Chemicals (30%)

• DNA (1%)
• Phospholipids (2%)
• Polysaccharides (2%)
• Ions, small molecules (4%)
• RNA (6%)
• Proteins (15%)

All the biological molecules considered (with the exception of water) are carbon-based.

Carbon atoms can bond together to form long chains and rings.

Other atoms can bond to the rings and chains to form many different molecules with different structures and properties.

Because of this multiple-bonding feature, carbon is a kind of framework atom that can form the basis of all the biological molecules necessary for life.