Question

What signals are required to pass a cell through the restriction point between G1 and S phase?

Answer 1

The signals required to pass a cell through the G1 checkpoint include external growth factors, adequate reserves and cell size, and a check for genomic DNA damage.

Step-by-step explanation:

The signals required to pass a cell through the restriction point between G1 and S phase include:

1. External growth factors: These signals play a large role in carrying the cell past the G1 checkpoint.
2. Adequate reserves and cell size: The cell must have enough resources and be of sufficient size to proceed to the S phase.
3. Check for genomic DNA damage:
4. A cell that has DNA damage will not be allowed to progress into the S phase.

If the cell does not meet these requirements, it can halt the cell cycle and attempt to fix the issues, or it can enter a state called Go and wait for conditions to improve.