Biology Revision Notes

Homeostasis is defined as the maintenance of constant internal conditions within organisms. The principle can be developed in a wide range of contexts, including the maintenance of balanced water leve click here for full revision note

All organisms respond to chnges in their environment and this section explores some of the ways in which they do this. The human eye is studied as an example of a receptor organ.Stimuli: Changes in ex click here for full revision note

This section introduces respiration as a process for transferring energy from food (e.g. glucose) to the cells of an organism. Oxygen is normally required for respiration and carbon dioxide is produce click here for full revision note

This section allows transport systems to be examined. The need for transport systems in large organisms is considered, together with the ways in which the major transport systems of plants and mammals click here for full revision note

This section provides the opportunity for investigating how the human breathing system allows the exchange of fases between alveoli and the blood caplillaries. The effects of cigarette smoke on health click here for full revision note

This section examines the physiology of photosynthesis and how it related to agriculture and food production. The value of photosynthesis as an oxygen producing process is examined and is related to t click here for full revision note

Digestion is presented as a means of transforming complex food substances into smaller molecules prior to absorption into the body. The functions of the human digestive systems are examined, as well a click here for full revision note

This section looks at the cell as the basic unit from which most living organisms are constructed. The pats of a cell are identified and their functions considered. Differences between plant and anima click here for full revision note

All organism within a group show certain common characteristics that have been used to place them in that group. Organisms have a large number of different characteristics, many of which enable them t click here for full revision note