B2.1.4 - Mitosis Flashcards
Why do our body cells divide to produce more cells?
To replace worn out cells, to repair damaged tissue and to enable the organism to increase in size
What is mitosis?
It is the process in which body cell divide and each produces 2 identical daughter cells
What happens in the first stage of mitosis?
In the first stage each cell produces a new set of genetic material
Each chromosome is made of molecule of DNA so in order to copy a chromosome, its DNA must be replicated
How is DNA replicated?
the DNA molecules unzips forming 2 separate strands
the DNA bases on each strand are exposed
Free nucleotides in the nucleus line up against each of the stands they bind to (A-T,C-G)
This forms DNA base pairs
When the whole strand is complete there are 2 identical molecules of DNA
How do chromosomes move in the second stage?
The chromosomes line up across the centre of the cell
The identical copies of each chromosome move to each end of the cell
Each end now has a full set of identical chromosomes
2 nuclei then form
What is cytokinesis?
Following the movement of the chromosomes, the cell membrane pinches inwards to separate and enclose the 2 nuclei and then pinches of to produce 2 identical daughter cells
