Cell division

Question 1

What are the 3 phases of interphase?
2 phases of mitosis and explain what happens?

Answer 1

Interphase:
- growth phase 1
- synthesis
- growth phase 2
Mitotic phase:
- mitosis= nucleus divides
- cytokinesis= cytoplasm divides & 2 daughter cells produced

Question 2

What is G0? Why might a cell enter G0?

Answer 2

The resting phase, in which the cell leaves the cycle temporarily or permanently
When a cell is specialized it no longer needs to divide, hence entering G0

Question 3

Which cells DON’T divide?

Answer 3

DNA damaged cells and senescent cells

Question 4

What happens at each checkpoint of the cell cycle? (3)

Answer 4

G1 checkpoint checks for:
cell size, nutrients, growth factors, DNA damage

G2 checkpoint checks for:
cell size, DNA replication, DNA error

Spindle assembly checkpoint checks for:
all chromosomes attached to spindles and being aligned

Question 5

What happens at G1 phase?

Answer 5

• proteins synthesised
• organelles replicated
• cell enlarges

Question 6

What happens at synthesis phase?

Answer 6

• DNA replicated

Question 7

What happens at G2 phase?

Answer 7

• energy stores are increased
• DNA checked for errors
• cell enlarges