Importance of Mitosis: -

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Importance of Mitosis -

• Each of the daughter cells are identical to each
  other and to the parent cell.
• Mitosis is how new cells are produced for growth
  and repair. The body need more of the same
• In some organisms mitosis is also their form of
  reproduction.
• E.g. in yeast (Saccharomyces cereviciae)
• in Hydra (Hydra cnidaria)
• in many types of plant (strawberries,
  potatoes)

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Meiosis

• A different type of cell division.
• One that doesnt for genetically identical cells.

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Meiosis occurs in organisms that have a sexual
life cycle.
Meiosis is a special form of cell division that
only occurs in specialized organs involved in
sexual reproduction.
The sperm and eggs have half the number of
chromosomes of the parent cells.

• Sperms and Eggs are said to have n number of
  chromosomes (the haploid number).
• Normal body cells (somatic cells) are said to
  have 2n number of chromosomes (i.e. they diploid
  number). They have two copied of each chromosomes.

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• It is different from mitosis in three very
  important ways -
• Meiosis produces cells that contain half the
  number of chromosomes.
• Meiosis produces four daughter cells as opposed
  to two.
• Meiosis produced cells that are genetically
  different from each other, and from the parent
  cell.

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The body cells of humans have two set of
chromosomes. The two chromosomes of a kinds are
homologous chromosomes.

• This refers to the fact that the chromosomes
  have genes for the same features in the same
  positions.

This doesnt mean the genes are the same. Each
gene has many different varieties (e.g. the
different alleles for eye colour)
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