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Reproduction (Produces genetically different cells (Sexual reproduction is…
Reproduction
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Asexual reproduction
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Bacteria, some plants and some animals reproduce asexually
Meiosis
Gametes are produced through meiosis - involves 2 cell divisions and in humans only happens in the reproductive organs
Before the cell starts to divide, it duplicates its genetic material, forming 'two armed chromosomes' - one arm is exact copy of other arm, and after replication the chromosomes arrange themselves into pairs
In the first division the chromosome pairs line up n the centre of the cell, and are then pulled apart so each new cell only has one copy of each chromosome
In the second division the chromosomes line up again in the centre of the cell and the arms of the chromosomes are pulled apart
Four gametes are formed with only a single set of chromosomes, and each gamete is genetically different to the others as the chromosomes were given out at random
Replication
After the gametes have fused during fertilisation, the new cell divides by mitosis to make a copy of itself
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As the embryo develops, these cells then start to differentiate into the different types of specialised cells that make up an organism
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X and Y chromosomes
23 pairs of chromosomes in human body of which 22 are matched pairs but 23rd pair are labelled XY or XX - the two chromosomes which decide your sex
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When making the sperm chance of an X or a Y is 50%, but all eggs get an X chromosome
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