Final answer:
The experiment that would help determine whether the β-galactosidase gene is induced by lactose or glucose is to measure the activity of β-galactosidase in the presence of both lactose and glucose.
Step-by-step explanation:
The experiment that would help determine whether the β-galactosidase gene is induced by lactose or glucose is option 3) Measuring the activity of β-galactosidase in the presence of both lactose and glucose.
This experiment is important because it allows us to see if the presence of both lactose and glucose affects the activity of β-galactosidase. If the activity of the enzyme is significantly different when both lactose and glucose are present compared to when only one of them is present, it suggests that the gene is responsive to both sugars.
On the other hand, if the activity of the enzyme remains the same regardless of the presence of both sugars, it indicates that the β-galactosidase gene is specifically induced by lactose and not by glucose.
To determine whether the β-galactosidase gene is induced by lactose or glucose, it's important to perform experiments to measure the activation of the lac operon under various conditions. The lac operon includes genes that code for enzymes such as β-galactosidase, lactose permease, and transacetylase, which are used to metabolize lactose when glucose is not available.
Experiment 1) Measuring the activity of β-galactosidase in the presence of lactose can show if lactose induces enzyme production. Experiment 2) Measuring enzyme activity in the presence of glucose can reveal if glucose has a repressive effect on the lac operon. Experiment 3) Observing enzyme activity in the presence of both sugars can demonstrate the preferential use of glucose over lactose. Experiment 4) Measuring the enzyme's activity in the absence of both sugars can act as a control to show the baseline activity of the operon without inducers.