Question

For genotype: lacIS lacP+ lacO+ lacZ - lacY+ / F' lacI+ lacP+ lacOC lacZ+ lacY -

Select the best description of beta-galactosidase activity in the following environmental conditions.
Lactose Absent; Glucose Absent
Lactose Present, Glucose Present
1. High
2. Basal
3. Lower than basal
4. None
For genotype: lacIS lacP+ lacO+ lacZ - lacY+ / F' lacI+ lacP - lacOC lacZ+ lacY -
Select the best description of permease activity in the following environmental conditions.

Answer 1

In the absence of lactose and glucose, beta-galactosidase activity is basal. In the presence of lactose and glucose, beta-galactosidase activity is lower than basal.

Step-by-step explanation:

For the given genotype, lacIS lacP+ lacO+ lacZ- lacY+ / F' lacI+ lacP+ lacOC lacZ+ lacY-

In the absence of lactose and glucose, the lac operon is in a repressed state and the beta-galactosidase activity is basal, meaning it is at a low level. This is because glucose levels are high and lactose is absent.

In the presence of lactose and glucose, the lac operon is not fully activated, but it is partially induced. The beta-galactosidase activity is lower than basal, meaning it is slightly above the low level seen in the repressed state. This is because glucose levels are low or non-existent and lactose is present.