Why do cells have different shapes?
OBJECTIVE: Describe and relate the structures and functions of different kinds of cells. Key Terms unicellular: containing only one cell multicellular: containing more than one cell pseudopod (SOO-duh-pahd): fingerlike extension of the cytoplasm guard cells: cells that control the size of the stoma stoma, pl. stomata: tiny openings on the underside of a leaf Lesson Summary Unicellular organisms have only one cell. An amoeba is an example of a unicellular organism. Multicellular organisms are made of more than one cell. Cells come in different sizes and shapes. The shape of a cell is usually related to its job or function. Red blood cells are round and are very flexible. They can bend and fold to fit into small capillaries. Guard cells in plants shrink and swell to allow for oxygen, carbon dioxide, and water to pass in and out of the cell. 2-7 How do materials move in and out of cells? OBJECTIVE: Describe how materials can move in and out of cells. Key Terms diffusion (dih-FYOO-zhuhn):
