Nutrition is the supply of nutrients to the cells of living organisms for the purpose of providing energy, growth and repair of the body tissues. It involves a series of processes by which living things obtain and utilise food materials. Food is the source of nutrients. The utilisation of food is accompanied by the release of energy, which is used in carrying out some life processes such as growth, movement, transportation of materials and reproduction. In plants, food materials are first synthesised and then distributed to different parts of the body.
In animals, the food materials are taken in the form of complex compounds. These are broken down into simpler forms which can easily be absorbed into the cells after the process of digestion. The two main chemical reactions that take place within the cells are anabolism which has to do with the process of synthesis, e.g. (photosynthesis) and catabolism which deals with degradation of food e.g. (respiration).
(ii) Conditions for photosynthesis
(iii) Significance and evidence of photosynthesis
(b) Mineral requirement of plants
(i) Essential and non-essential elements
(ii) Effects of mineral deficiency
(c) The nitrogen cycle
(a) Food substances
(ii) Classes and examples
(b) Balanced diet
(c) Food tests
(d) Digestive enzymes
(i) Classes and functions
(v) Carnivorous plants