The G1 Checkpoint: Ensuring Adequate Supply of Energy and Raw Materials

Which checkpoint describes an ample supply of energy and raw materials that are available?

A) G1 checkpoint
B) G2 checkpoint
C) M checkpoint
D) S checkpoint

Answer

The G1 checkpoint describes an ample supply of energy and raw materials available in a cell.

The G1 checkpoint, also known as the restriction point, plays a crucial role in the cell cycle by ensuring that the cell has enough energy and raw materials for division. This checkpoint serves as a quality control mechanism to determine if the conditions are favorable for the cell to proceed to the next phase.

At the G1 checkpoint, the cell checks for various factors such as cell size, availability of energy sources, and the integrity of genomic DNA. If the cell meets all these requirements, it will be given the green light to enter the S phase and initiate DNA replication.

However, if the cell fails to meet the criteria at the G1 checkpoint, it may either try to rectify the issues or enter a resting phase known as the G0 phase. In the G0 phase, the cell remains dormant until conditions improve and signal the cell to re-enter the cell cycle.

Overall, the G1 checkpoint ensures that the cell is adequately prepared for division by checking for the necessary resources and conditions needed for successful cell growth and proliferation.