Tumour pathology 4 Flashcards
Describe the G1 phase
- Cell increases in size
- G1 checkpoint control ensures cell is ready for DNA synthesis
Describe the S (interphase) phase
DNA replication occurs
Describe the G2 phase
- Cell continues to grow
- G2 checkpoint ensures cell is ready for mitosis
Describe M (mitosis) phase
- Cell division
- Metaphase checkpoint ensures cell is ready to complete division
Mechanisms of cell cycle control
- Quality control
- Checkpoints
- External factors
- Intrinsic factors
Describe quality control
Ensures genetic fidelity in daughter cells
- Each cells receives full chromosome complement
- Mutations in DNA sequences not passed on
Describe checkpoints
Monitor and regulate progress
Describe external factors
Hormones, growth factors, cytokines
Describe intrinsic factors
Critical checkpoints - restriction point
Describe the G0 (quiescent) phase
Resting phase; cell has left cycle and stopped dividing
Cells that don’t divide stay in G0 - cardiac and neuronal cells
What checkpoint is used if cell is too small?
G1 and G2
What checkpoint is used if nutrient supply is low?
G1
What checkpoint is used if external stimulus is lacking/
G1
What checkpoint is used if DNA not replicated?
S
What checkpoint is used if DNA damage is detected?
G1 and G2