Question

The process of 'turning on the expression of genes' due to environmental conditions is called

• A. Constitutive expression
• B. Induction
• C. Repression
• D. Enzymatic catabolism

Hint:

To easily remember these terms:
- Induction = "In" (Turn genes on activate).
- Repression = "Repress" (Turn genes off deactivate).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Gene regulation allows organisms to respond to environmental changes by synthesizing specific proteins only when they are needed.
This prevents the waste of cellular resources and energy on unnecessary protein synthesis.

Step 3: Detailed Explanation:
Let us look at the processes described in the options:
Induction: This is the process where gene expression is activated (turned on) in response to an environmental signal or substrate, called an inducer.
For example, the presence of lactose induces the transcription of the lac operon.
Constitutive expression: This refers to the continuous, unregulated expression of genes ("housekeeping genes") that are required for basic cell survival and are expressed at a constant rate.
Repression: This is the process of turning off gene expression in response to an environmental signal (co-repressor).
For example, high tryptophan levels repress the transcription of the tryptophan biosynthesis operon.
Therefore, the process of turning on gene expression in response to environmental conditions is called induction.

Step 4: Final Answer:
The activation of gene expression by environmental factors is called induction, matching Option (B).