Control of cell Number Flashcards
Describe how and when cell number is regulated
1
Q
What is involved in cell division?
A
- CDK
- cyclin proteins
2
Q
What does CDK do?
A
- phosphorylates proteins required for particular phases
- specific CDKs exist for specific phases of the cell cycle
3
Q
What do cyclin proteins do?
A
- activate CDK
- many different cyclins are made checks the cell to allow passing to the next phase
- specific cyclins are made and degraded at certain times during the cell cycle-hence their name cyclin
4
Q
What are the two signals a cyclin-CDK receive?
A
- cell growth signals
- growth inhibitory signals
5
Q
What does the CDK-cyclin complex do?
A
phosphorylates proteins required for particular phases
6
Q
What are examples of regulation?
A
- DNA damage inhibits entry to S until DNA damage is repaired
- During development many types of cells require stimulation to divide or undergo programmed cell death
7
Q
What are the major check points in cell cycle?
A
- G1/S checkpoint: entry into S phase
- G2/M checkpoint: entry into mitosis
- mitosis checkpoint
8
Q
What happens in the G1/S checkpoint?
A
- enough nutrients?
- large enough?
- growth factors present?
- DNA undamaged?
9
Q
What happens in the G2/M checkpoint?
A
- large enough?
- DNA replication is completed
- DNA is undamaged?
10
Q
What happens in the mitosis checkpoint?
A
-replicated chromosomes are properly attached to mitotic spindle
