Touching Lives - October 2008
Bacteria are single celled living organisms with a distinct cell wall. They reproduce by the division of one cell into two, when the conditions are favourable. If the conditions are unfavourable some types can form spores, which can survive for years. Bacteria are small and occur as spheres, rods, or even spirals with dimensions of a few microns (1 micron is 1/1000 of a millimetre). They are everywhere — one gram of soil may contain 40 million bacteria. The vast majority are harmless, a few are beneficial and some cause diseases (pathogenic). Many antibiotics work by interfering with the construction of the cell wall; a naked bacterium cannot survive.
The Central Nervous System: Instructions to move muscles or signals from sensory organs are carried by nerve fibres. To use an analogy, nerve fibres are like the telephone system of a small town. The wires from the individual telephones are collected together in larger cables, which then all join one big cable. In our bodies this is the spinal cord and it leads to the back of the brain. Together the fibres and the brain comprise the Central Nervous System (CNS). But here the analogy must end because the CNS is not just a telephone exchange. The incoming information is processed and what comes out is very different.
Phosphate: Phosphorus is an element and its salts are called phosphates. They are found as minerals, and play a vital part in the metabolism and structure of all living organisms. Phosphate is also very important in making the stiff structural components in bones. A bone is made from a protein called collagen, which is quite flexible (your outer ear is made from it, covered in skin), in which crystals of hydroxyapatite, a form of calcium phosphate, are embedded. These give the bones their strength. Bones have the marvellous ability to adjust their strength according to the imposed load, largely by adjusting the amount of mineral content.