Cells are the basic building blocks of all living things. All cells are small 'sacks' composed mostly of water. There are millions of different types of cells, but they are divided into two main groups. The first group, Prokaryotes, is made up of very small cells that have no membrane around their nucleus and no organelles with membranes. Prokaryotes include bacteria and are the most common type of cell. The second group of cells is called Eukaryotes. There are many different types of Eukaryotes, but all types share some characteristics. The basic eukaryotic cell has a cell membrane which is also known as a plasma membrane. It has a nucleus, cytoplasm, a cytoskeleton, and membrane-covered organelles.
The organelles inside a cell have special jobs that let the cell function like it is supposed to. Each type of organelle has its own individual shape and size. The number of organelles that a specific cell contains depends on what function the cell performs. An example of this would be a cell that uses up a lot of energy would have many mitochondria. Some cells have organelles that other cells do not have. An example of this is the chloroplast in the plant cell. Animal cells do not have chloroplast. Some organelles are very differen
ukreferencesencyclopaediahutchinsonm0015140. Cell sap is made up of a watery solution of salts and sugars that are kept at relatively high concentrations because of the movement of ions through the vacuole membrane. Food vacuoles are the most basic digestive compartments. Plants store these ions for later use. In the animal cell, the vacuoles are small spaces inside the cell which contain the necessary things for the cell to grow and reproduce. Contractile vacuoles are a special kind of vacuole whose main job is to pump water and other substances out of a cell to prevent the cell from bursting.