Cells and their parts Essay -- essays research papers

Cells are some of the smallest organisms around. All living things consist of cells, and yet they are invisible to the naked eye. Cells are the basic structural and functional units of life. Cells are made up of many different parts which allow them to function properly. All cells are separated from their surrounding by a cell membrane. The cell membrane regulates what enters and leaves the cell and also aids in the protection and support of the cell. A cell membrane is similar to the walls surrounding your house. In plants the cell membrane is surrounded by a cell wall. The cell wall is outside the cell membrane, and its purpose is to help the membrane protect and support the cell. Since the cell wall is very porous, water, oxygen, carbon dioxide, and other substances can pass through easily. A cell wall is similar to a fence around your house, because it helps protect other things from getting inside the cell. In many cells there is a the nucleus, which was first described by Robert Brown. If a cell does or does not have a nucleus has been used by scientists to divide cells into two general categories. The two categories are Eukaryotics, which are cells with a nucleus, and Prokaryotic, which are cells without a nucleus. The nucleus has been found to be the information center of the cell and contains DNA. It also directs all activities that occur in a living cell. It’s like a mini me of the heart and brain of a human body. Most nuclei contain a small area called the nuc...