Cell division - B3d

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  • Created by: iram_f
  • Created on: 11-01-15 16:50
What occurs during mitosis?
1) The chromosomes are copied and condense into X shapes. 2) They line up in the middle and spindles form. 3) The spindles pull the chromosomes to the poles. 4) Once at the poles the cell divides.
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What occurs during meiosis?
1) The chromosomes are copied and condense into X shapes. 2) They cross over to swap sections of DNA (genes), producing genetic variation. 3) The cell with 4 chromosomes divides and the 2 chromosomes in each cell move to the poles, and divide again.
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How is the structure of a sperm cell adapted to its function?
During fertilisation millions of sperm is released and they have large numbers of mitochondria to release energy for motion, to swim to the egg. It also has an acrosome on the head that releases an enzyme to digest the egg's cell membrane.
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Why are gametes haploid?
Gametes are haploid, meaning that they have half a set of chromosomes, so when fertilisation occurs male and female gametes fuse together and the zygote is diploid.
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What are the key differences between mitosis and meiosis?
Mitosis occurs for growth, repair & replacement of body cells. It produces 2 gen. identical diploid cells, with 1 division. Meiosis occurs to create gametes in the reproductive organs. It produces 4 gen. different haploid cells in 2 divisions.
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What happens during DNA replication?
First the chromosome unwinds form its double helix shape and then unzips to form two single strands. The base pairs separate and the bases then pair up in the complementary base pairings to create two new strands.
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Other cards in this set

Card 2

Front

What occurs during meiosis?

Back

1) The chromosomes are copied and condense into X shapes. 2) They cross over to swap sections of DNA (genes), producing genetic variation. 3) The cell with 4 chromosomes divides and the 2 chromosomes in each cell move to the poles, and divide again.

Card 3

Front

How is the structure of a sperm cell adapted to its function?

Back

Preview of the front of card 3

Card 4

Front

Why are gametes haploid?

Back

Preview of the front of card 4

Card 5

Front

What are the key differences between mitosis and meiosis?

Back

Preview of the front of card 5
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