Cell division Flashcards
In unicellular organisms what is cell division coupled to?
Growth and nutrient avaliability
In multicellular organisms what is cell division coupled to?
Motigen stimulus and cell death, as must make sure the correct number of cells in a tissue is maintained
What is the purpose of the GAP phases?
- allow time for cell growth and monitoring of the external environment
- Allows for the assessment of cell condition
At what point can cells exit the cell cycle? What is the possible effect of this?
G0 Can become temporarily or permanently aquiescent
At what phase does a cell become committed to divide?
S phase
What happens in G1?
The phase in which cells are monitoring mitogenic stimuli
What happens in G2?
Important cells growth and for monitoring DNA damage
What is mitosis?
The breakdown of the nuclear envelope and separation of duplicated chromosomes
What is cytokinesis?
Separation of the cell into 2 different, functional daughter cells
What model organisms are used to study cell cycle regulation?
- Yeast
- Frog eggs
How is mitosis coupled in fission yeast?
- Coupled to growth
- Grow from one end and once large enough then they divide
What does wee1 act on?
cdc2
What occurs in wee mutants?
Cells divided too quickly and so became smaller with each generation
How does wee1 control mitosis?
Acts as a brake by acting on cdc2 , when conditions for division weren’t met then wee1 would put a brake on division
How does cdc25 control mitosis?
Acts on cdc2 and acts as an accelerator
