Cell Cycle Checkpoints in Eukaryotic Cells
What are the major checkpoints for cell cycle control in a eukaryotic cell?
a) G1/S checkpoint
b) G2/M checkpoint
c) Metaphase checkpoint
d) Anaphase checkpoint
Final answer: The metaphase checkpoint
Answer:
The major checkpoints for cell cycle control in a eukaryotic cell are:
a) G1/S checkpoint
b) G2/M checkpoint
c) Metaphase checkpoint
d) Anaphase checkpoint
Final answer: The metaphase checkpoint
In a eukaryotic cell, there are three major checkpoints that play a crucial role in cell cycle control:
1. G1/S Checkpoint:
The G1/S checkpoint is the first major checkpoint in the cell cycle. It evaluates whether the cell is ready to progress from the G1 phase to the synthesis (S) phase. At this checkpoint, the cell checks for DNA damage, cell size, and availability of nutrients.
2. G2/M Checkpoint:
The G2/M checkpoint occurs before the cell enters the mitosis (M) phase. It ensures that the DNA has been accurately replicated during the S phase. If there are any errors or incomplete replication, the cell cycle is halted at this checkpoint.
3. Metaphase Checkpoint:
The metaphase checkpoint occurs during metaphase, just before the cell enters anaphase. This checkpoint confirms whether all the chromosomes are properly aligned at the metaphase plate. If any chromosome is misaligned, the cell division process is paused to prevent unequal distribution of genetic material to daughter cells.
These checkpoints help maintain the integrity of the cell cycle and prevent abnormal cell growth, which can lead to conditions like cancer.