In this topic we are learning to: z Compare plant and animal cells. z Outline the role of cell organelles, including the cell membrane, cytoplasm and nucleus.
Using a light microscope, we may also be able to see certain cell organelles. Organelles are small structures that carry out specific roles within the cell. Each organelle has a different job to do in the cell. The three main organelles in both animal and plant cells are:
1. Cell membrane: surrounds the cell and controls which materials move into and out of the cell.
2. Cytoplasm: a jelly-like substance surrounded by the cell membrane. Contains other organelles, including the nucleus, and dissolved substances such as oxygen.
3. Nucleus: the control centre of the cell. The nucleus contains DNA (genes). We will learn more about them in Chapter 4.
Plant cells also have a cell wall and chloroplast. These two organelles are not found in animal cells.
1. Cell wall: strengthens the cell. Cell walls make plant cells stronger than animal cells.
2. Chloroplast: contain chlorophyll, which allows the plant cell to absorb sunlight energy for photosynthesis.
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Vacuoles are membrane-bound structures that contain liquids. Animal cells contain small vacuoles. Plant cells often contain larger vacuoles full of water.
