Use the following choices to answer questions 7 and 8:
a. catabolite repression
b. DNA polymerase
c. induction
d. repression
e. translatio


The mechanism by which lactose controls the lac operon.

Verified step by step guidance

1. Identify the role of lactose in the lac operon system.
2. Understand that the lac operon is a set of genes involved in lactose metabolism in bacteria.
3. Recognize that lactose acts as an inducer in the lac operon system.
4. Determine that the presence of lactose leads to the activation of the lac operon by removing the repressor protein from the operator site.
5. Conclude that the correct choice for the mechanism by which lactose controls the lac operon is 'induction'.

Key Concepts

Lac Operon

The lac operon is a set of genes in E. coli that are responsible for the metabolism of lactose. It consists of three structural genes (lacZ, lacY, and lacA) and is regulated by the presence or absence of lactose and glucose. Understanding the lac operon is crucial for grasping how bacteria adapt to different sugar sources and how gene expression is controlled in prokaryotes.

Induction

Induction is a regulatory mechanism in which the presence of a specific molecule, such as lactose, activates the expression of genes. In the case of the lac operon, when lactose is available, it binds to the repressor protein, causing it to release from the operator region, thus allowing transcription of the operon. This process exemplifies how environmental signals can influence gene expression.

Repression

Repression is a process by which the expression of a gene or operon is inhibited, often by a repressor protein binding to the operator region. In the lac operon, when glucose is present and lactose is absent, the repressor remains bound, preventing transcription. This mechanism ensures that bacteria prioritize energy-efficient pathways, highlighting the interplay between different metabolic signals.