Mitosis

How do living things grow and repair themselves?

Why do cells divide?

Reproduction Growth Repair

The cell cycle

Regular sequence of growth and division of cell

3 parts:– Interphase– Mitosis– Division of cytoplasm

1. Interphase

Longest part of cell cycle

Cell grows to mature size

To prepare to divide, each chromosome makes a copy of itself

Length of interphase

Different kinds of cells spend different lengths of time in interphase

Human skin cells Human bone cells

2. Mitosis

Part where cell’s nucleus divides into two identical new nuclei

4 stages of mitosis (PMAT):– Prophase– Metaphase– Anaphase– Telophase

Prophase

Spindle forms Centrioles move to

opposite poles Chromosomes

become visible

Metaphase

Chromosomes line up along the equator

Anaphase

Chromosomes and duplicates separate and move to opposite poles

Telophase

Nuclear membrane forms around each group of chromosomes

Chromosomes unwind

Cytoplasm starts to divide

End result of mitosis

Two identical daughter cells Both cells have the same number of identical

chromosomes

3. Division of cytoplasm

Cytoplasm divides and one cell becomes two new cells with identical nuclei

Animal cells Plant cells