3.1 Introduction
1. Explain how cells differ from one another.

3.2 Composite Cell
2. Explain how the structure of a cell membrane makes possible its functions.
3. Describe each type of organelle, and explain its function.
4. Describe the parts of the cell nucleus and its parts.

3.3 Movements Through Cell Membranes
5. Explain how substances move into and out of cells.

3.4 The Cell Cycle
6. Explain why regulation of the cell cycle is important to health.
7. Describe the cell cycle.
8. Explain how stem cells and progenitor cells make possible growth and repair of tissues.
9. Explain how two differentiated cell types can have the same genetic information, but different appearances and functions.