Meiosis.

How meiosis occurs.

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  • Created by: Nick
  • Created on: 26-02-12 20:41

Why?

- Gametes have half the usual number of chromosomes (23). They are haploid (one copy of each chromosome)

- Gametes are sex cells (Ova = female, Sperm = male).

- The two gametes combine during reproduction to form a new cell. (46 chromosomes).

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How?

- Before the cell divides it duplicates it's DNA. (as with Mitosis)

- In the first of two divisions in meiosis the chromosome pairs line up in the centre of the cell.

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How?

- They're pulled apart so each new cell only has one copy of each chromosome. 

- Each new cell is made up of chromosomes from both the mother and father.

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How?

- Each new cell has a mixture of chromosomes from the mother and the father.

- This provides variation in the offspring.

- Huge advantage of sexual reproduction over asexual.

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How?

- In the second division the chromosomes line up again in the centre of the cell.

- The arms of the chromosomes are pulled apart (like Mitosis).

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How?

- You get 4 gametes.

- They have a single set of  chromosomes each (23).

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Comments

Elissa

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thanks this cleared up the differences it has from mitosis

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