Basic Cell Biology

Most cells are made up of similar components: a nucleus, the part of the cell containing genetic information; a variety of organelles, sub-cellular structures that carry out specific functions required by the cell, analagous to the way that different organs carry out specific functions of the body (e.g. lysosome, mitochondrion, golgi etc); the cytoplasm, the liquid in which the nucleus and organelles are suspended, and the plasma membrane, the structure that surrounds the cell and maintains its shape. A typical cell is shown in the diagram below:

In many ways, it is the nucleus that is the most important organelle of a cell, in that it contains all the information necessary to produce each constituent of the cell. Each organelle and cellular structure is made up of protein, sugars and lipids (fatty compounds), and the nucleus not only contains the blueprint for the production of each of these components, but also the information necessary for their correct assembly and final location. This information is contained within the cell's DNA, which is the major consituent of the nucleus and is tightly condensed in a highly organised manner within the nuclear membrane.