Question

Label parts B to D in the Lac operon diagram.

Hint:

Use the mnemonic: "Z-Y-A $\rightarrow$ B-P-T" (Beta-gal, Permease, Transacetylase).

Answer 1

Step 1: Understanding the Concept:
The structural genes \( z, y, \text{ and } a \) in the Lac operon code for three different enzymes required for lactose metabolism.
Step 2: Detailed Explanation:
1. Label B (from 'z' gene): This codes for $\beta$-galactosidase. This enzyme hydrolyzes lactose into glucose and galactose.
2. Label C (from 'y' gene): This codes for Permease. This enzyme increases the permeability of the cell to $\beta$-galactosides (lactose).
3. Label D (from 'a' gene): This codes for Transacetylase. It transfers an acetyl group from acetyl-CoA to $\beta$-galactosides.
Step 3: Final Answer:
B is $\beta$-galactosidase, C is Permease, and D is Transacetylase.