Question

In the _____ loss of function mutation in the yeast Saccharomyces pombe, there is no M-Cdk inactivation and the cell enters M-phase even if it has not grown enough.

Answer 1

In a loss of function mutation in Saccharomyces pombe, cells may enter mitosis prematurely due to a lack of M-Cdk inactivation, potentially leading to additional mutations.

Step-by-step explanation:

In the loss of function mutation in the yeast Saccharomyces pombe, there is no M-Cdk inactivation and the cell enters M-phase prematurely. This is because the mutation likely interferes with the cell's regulatory mechanisms at the G1 checkpoint. In a similar scenario, loss of p53 function in other organisms might lead to the failure to produce p21, which normally inhibits Cdk activation. Without this inhibition, the G1 checkpoint can't properly monitor and control cell growth before DNA replication begins in the S-phase. The premature entry into the M-phase could result in cell division before adequate growth, possibly leading to the accumulation of further mutations.