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BIO - 2.1.6 Cell Division > Mitosis > Flashcards

Flashcards in Mitosis Deck (8)
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1

Importance of mitosis

- Mitosis ensures that both daughter cells produced when a parent cell divides are genetically identical.
- Needed for growth of multicellular organisms and for repairing damaged tissues.
- Some animals, plants and fungi also use it to reproduce asexually.
- PMAT+C (Prophase, Metaphase, Anaphase, Telophase + Cytokinesis)

2

Chromosomes

- Before replication, 1 chromosome has 1 chromatid (strand).
- After replication, chromosome has 2 chromatids.
- Centromere is the middle region where 2 chromatids are joined together.
- 2 strands on the same chromosome are called sister chromatids.

3

Prophase

1. Chromosomes condense, getting shorter and fatter.
2. Centrioles start moving to opposite ends of the cell, forming a network of protein fibres across it called the spindle.
3. Nuclear envelope breaks down and chromosomes lie free in cytoplasm.

4

Metaphase

1. Chromosomes line up on the spindle equator and become attached to spindle by their centromere.

5

Anaphase

1. Centromeres divide, separating each pair of sister chromatids.
2. Spindles contract, pulling chromatids to opposite ends of the cell, centromere first.

6

Telophase

1. Chromatids reach opposite poles on spindle.
2. They uncoil and become long and thin again.
3. They're now called chromosomes again.
4. A nuclear envelope reforms around the 2 groups of chromosomes.
5. So there are 2 nuclei.

7

Cytokinesis

1. The cytoplasm divides.
2. In animal cells a cleavage furrow forms around the middle of the cell.
3. There are now 2 daughter cells that are genetically identical to the original cell and to each other.

8

Investigating mitosis

1. Stain the chromosomes so you can see them under a microscope. This allows you to see what happens during mitosis.
2. Make a squash microscope slide. Squashes can be made by treating the root tips with hydrochloric acid.
3. Add stain and then physically squish cells beneath cover slip.