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


Mechanism by which the presence of glucose inhibits the lac operon.

Verified step by step guidance

1. Identify the mechanism that involves the inhibition of the lac operon in the presence of glucose.
2. Recall that the lac operon is a set of genes responsible for the metabolism of lactose in bacteria.
3. Understand that when glucose is present, bacteria prefer to use it over lactose, leading to the inhibition of the lac operon.
4. Recognize that this process is a regulatory mechanism that prevents the expression of genes involved in lactose metabolism when glucose is available.
5. Match this description with the provided choices to identify the correct term.

Key Concepts

Catabolite Repression

Catabolite repression is a regulatory mechanism in bacteria that prioritizes the use of certain carbon sources over others. When glucose is present, it inhibits the expression of genes involved in the metabolism of alternative sugars, such as lactose. This ensures that the cell efficiently utilizes the most energetically favorable substrate, thereby conserving resources and energy.

Lac Operon

The lac operon is a set of genes in E. coli that are responsible for the metabolism of lactose. It consists of structural genes that encode proteins necessary for lactose uptake and breakdown. The operon is regulated by the presence of lactose and glucose, with catabolite repression playing a key role in its inhibition when glucose is available.

Induction and Repression

Induction and repression are two fundamental mechanisms of gene regulation. Induction refers to the process by which a molecule (like lactose) increases the expression of a gene, while repression involves the inhibition of gene expression, often in response to the presence of a preferred substrate (like glucose). In the context of the lac operon, glucose presence leads to repression, preventing lactose metabolism.