Cells are the building blocks of life, i.e. they make up every living organism. There are unicellular organisms (made of one cell) and multicellular organisms (made of many cells).
Animal and plant cells have some common organelles: nucleus, cell membrane and cytoplasm. The nucleus contains the DNA, so controls what happens in the cell; they call it the brain of the cell. The cell membrane controls what goes in and out of the cell and the cytoplasm is the place where chemical reactions occur. There is another very important cell organelle, the mitochondrium. The important process of respiration happens there, so that cells can produce the energy to perform all their significant roles.
Plant cells contain additional organelles that aid them to perform photosynthesis. These are the chloroplasts that contain chlorophyll, a green pigment that collects light energy. Plant cells also have a cell wall around the cell membrane for additional strength and support. The cell wall is made of cellulose. Another plant organelle is the vacuole, filled with a liquid called cell sap. This provides support from the inside, called turgidity.
The diagrams below show an animal and a plant cell. Take a good look at them and then work through the following questions.