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GCSE Edexcel - Meiosis and Mitosis
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Mitosis
Multicellular organisms need cells to divide so that organisms can grow and repair damaged tissue. |
Cells divide when an organism grows or becomes damaged. |
Before a cell can divide, it must grow and make copies of all the organelles such as mitochondria and ribosomes. |
During mitosis, the two complete sets of chromosomes are pulled to opposite sides of the cell. |
Main Differences
| |
Mitosis |
Meiosis |
Number of cell divisions |
1 |
2 (meiosis I and II) |
Daughter characteristics |
Identical to each other and to parent cell, diploid |
All daughter cells are unique, haploid |
Biological significance |
Good for asexual reproduction, growth |
Production of gametes |
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Mitosis Stages
Interphase |
DNA copies itself ready for mitosis, cell spends the majority of its life in this phase |
Prophase |
The DNA in chromosomes and their copies condenses to become more visible. |
Metaphase |
Chromosomes and their copies line up in the middle of the cell. |
Anaphase |
Chromosomes and their copies are pulled to different ends of the cell. |
Telophase |
New membranes form around chromosomes at each end of the cells. |
Cytokinesis |
The cell membrane pinches in and eventually divides into two daughter cells. |
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Meiosis
Meiosis is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes. |
It produces four haploid non-identical cells. |
Meiosis produces haploid gametes, so that when they fuse, the diploid number of chromosomes is restored. |
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