Cells go through distinct phases of the cell cycle including growth, DNA replication, and cell division. The main stages are gap 1 (G1) involving cell growth, DNA synthesis (S) to copy DNA, gap 2 (G2) with more growth, and mitosis (M) where the cell nucleus and cytoplasm divide. The rate of cell division depends on the needs for that type of cell, with some cells not dividing at all. Cell size is limited due to faster volume than surface area growth, requiring unique cell shapes for cells that must be large.

1. KEY CONCEPT Cells have distinct phases of growth, reproduction, and normal functions.

2. The cell cycle has four main stages. The cell cycle is a regular pattern of growth, DNA replication, and cell division.

3. The main stages of the cell cycle are gap 1, synthesis, gap 2, and mitosis. Gap 1 (G 1 ): cell growth and normal functions Mitosis occurs only if the cell is large enough and the DNA undamaged. DNA synthesis (S): copies DNA Gap 2 (G 2 ): additional growth Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis)

4. Cells divide at different rates. The rate of cell division varies with the need for those types of cells. Some cells are unlikely to divide (G 0 ).

5. Cell size is limited. Volume increases faster than surface area.

6. Surface area must allow for adequate exchange of materials. Cell growth is coordinated with division. Cells that must be large have unique shapes.