1. Chapter 2.4 Specialized Cells

2. A multicellular organism cannot be made up only of identical cells. A multicellular organism cannot be made up only of identical cells.

3. Cells are specialized for particular tasks. Cells are specialized for particular tasks. Cells look different and have different jobs. Cells look different and have different jobs. Humans have about a hundred different types of cells, each with their own particular structure and function. Humans have about a hundred different types of cells, each with their own particular structure and function.

4. Examples Nerve Cells have long, branched fibres running from the main part of the cell, shaped to carry nerve signals. Nerve Cells have long, branched fibres running from the main part of the cell, shaped to carry nerve signals. Red blood cells carry oxygen in the bloodstream have a thin disc-like shape. Red blood cells carry oxygen in the bloodstream have a thin disc-like shape.

5. Unicellular Organisms One Cell. One Cell. Carries out all the functions in order to live. Carries out all the functions in order to live. Cannot grow very large. Cannot grow very large. Live in watery, food rich surroundings. Live in watery, food rich surroundings.

6. Multicellular Organisms Many cells. Many cells. Can live in a wide variety of environments. Can live in a wide variety of environments. Can grow large. Can grow large. Animals can obtain their energy from a wide variety of foods. Animals can obtain their energy from a wide variety of foods. Bodies are complex. Bodies are complex.

7. Questions Why do cells in your body need to be specialized? Why do cells in your body need to be specialized? Why do nerve cells have long fibres, whereas red blood cells are thin and disc- like? Why do nerve cells have long fibres, whereas red blood cells are thin and disc- like? Why do unicellular organisms live mainly in a watery environment? Why do unicellular organisms live mainly in a watery environment?

8. APPLY: Most people think of the skin as just a body covering. How do you think skin cells are important to other body cells? APPLY: Most people think of the skin as just a body covering. How do you think skin cells are important to other body cells?