Basic Biology -  Organisms and cells

The mitochondria are specialised for energy production (respiration). Chloroplasts are organelles found in plant cells which produce sugar using light. Light is the ultimate source of energy for almost all life on Earth. The area of the cell outside the nucleus and the organelles is called the cytoplasm. Membranes are complex structures and they are an effective barrier to the environment, and regulate the flow of food, energy and information in and out of the cell.

There is a theory that mitochondria are prokaryotes living within eukaryotic cells. An essential feature of most prokaryote and eukaryote living cells is their ability to grow in an appropriate environment and to undergo cell division.

The growth of a single cell and its subsequent division is called the cell cycle. However, not all cells continually grow and divide, for example neurons only undergo an initial growth phase. Prokaryotes, particularly bacteria, are extremely successful at multiplying - it is likely that natural selection has favoured single celled organisms able to grow and divide quickly.

Multicellular organisms typically begin life as a single cell, usually as a result of fusion of a male and a female sex cell (gametes). The single cell has to grow, divide and differentiate into different cell types to produce tissues and in higher eukarotyes (such as mammals), organs. Cell division and differentiation need to be controlled. Cancerous cells grow without control and can go on to form tumours. Development of single cells into complex organisms is in itself an area of study called developmental biology. The 2001's Nobel prize for Physiology or Medicine has been awarded to scientists for the discoveries of key regulators of the cell cycle.

The subject matter of bioinformatics is fundamentally concerned with understanding, manipulating and modifying the various stages of the cell cycle of organisms to enhance the quality of life and developement of the human race.


Next we will look at the molecule of life >>>