DNA The compound deoxyribonucleic acid a complex organic chemical with a spiral, double-helix structure. It is the 'brains' behind the workings of the living cell, and is made up of chains of nucleotides.
RNA The abbreviation for ribonucleic acid. It is an essential constituent of the living cell, where it carries 'instruction' from the DNA. It is made up of long chains of nucleotides.
Photosynthesis The process by which green plants make their food. They manufacture carbohydrates from the carbon dioxide in the air and from water absorbed from the soil, using the energy in sunlight. The green pigment chlorophyll is responsible for absorbing solar energy and converting it into chemical energy that the plants can use.
Respiration The process in which living things absorb oxygen ( to 'burn' their food and release energy ) and give out carbon dioxide ( as a waste product )