- Define mitosis as nuclear division giving rise to genetically identical cells in which the chromosome number is maintained by the exact duplication of chromosomes (details of stages are not required).
Learn the definition!!
- State the role of mitosis in growth, repair of damaged tissues, replacement of worn out cells and asexual reproduction.
Since mitosis gives rise to genetically identical daughter cells, mitosis is useful when we need more of the same type of cells for example:
In growth, body cells divide to form more of the same type of body cells e.g. hair cells divide to produce more hair cells, etc.
This is also important when repairing damaged tissue. For example, imagine you cut yourself. You have damaged your skin tissue, so now you need more skin cells to patch up the wound, and thus, mitosis is useful.
Mitosis is used in replacement of worn out cells for obvious reasons too.
Asexual reproduction relies on mitosis too, because this type of reproduction does not rely on the fusion of gamete nuclei, so mitosis ensures that chromosome number is maintained.
- Define meiosis as reduction division in which the chromosome number is halved from diploid to haploid (details of stages are not required).
A pretty self-explanatory point 😊
- State that gametes are a result of meiosis.
Gametes are a result of meiosis.
- State that meiosis results in genetic variation so the cells produced are not all genetically identical.
Meiosis results in genetic variation so the cells produced are not all genetically identical.
Let me explain:
We already know that each diploid cell has two sets of chromosomes, right?
So each corresponding chromosome has the same genes in the same order, but the alleles of each gene might be different.
This means that when meiosis occurs, and the chromosomes are split between the daughter cells, some daughter cells will get one of the alleles and the other daughter cells will get the other allele. Therefore, the daughter cells are not genetically identical and there is genetic variation.
Notes submitted by Sarah.
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