Mitosis and Variation
- Created by: amy24601
- Created on: 30-01-20 20:15
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- Mitosis and Variation
- Chromosomes
- each cell contains 46 chromosomes
- sperm and egg cells have 23 chromosomes each. this is so that when they join together to make a zygote those cells have 46 chromosomes
- You have two chromosomes for each gene or characteristic
- stages of mitosis
- stage 1: cell gets ready to divide. duplicates each of its chromosomes
- stage 2: chromosomes line up along the middle of the cell (the equator)
- stage 4: the cell splits and two new identical daughter cells are formed.
- stage 3: the identical chromatids are pulled apart by spindle fibres to opposite sides of the cell.
- variation
- a species is a group of organisms that can interbreed and produce fertile offspring.
- two animals can reproduce but if they're nor the same species their offspring will be infertile.
- continuous variation falls smoothly from one extreme to another. there isn't two distinct groups. eg- height or hair colour.
- discrete variation means you can divide a species into two distinct groups. eg- what hand you write with or if you can roll your tongue or not.
- Chromosomes
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