6.5 AP Bio Operons Week 25

Front

What is an operon?

Back

An operon is a cluster of genes under the control of a single promoter, which are transcribed together as a single mRNA molecule. It typically includes structural genes, a promoter, and an operator.

Front

What is the function of the operator in an operon?

Back

The operator is a segment of DNA that a repressor protein can bind to, blocking RNA polymerase from transcribing the genes in the operon.

Front

What role does RNA polymerase play in gene expression?

Back

RNA polymerase is the enzyme that synthesizes RNA from a DNA template during transcription, allowing for the expression of genes.

Front

What is a repressor in the context of operons?

Back

A repressor is a protein that binds to the operator region of an operon, preventing transcription of the associated genes.

Front

What is an inducer in an operon?

Back

An inducer is a molecule that binds to a repressor, causing it to change shape and release from the operator, allowing transcription to occur.

Front

What is the trp operon?

Back

The trp operon is a repressible operon in bacteria that is involved in the biosynthesis of the amino acid tryptophan.

Front

What is the lac operon?

Back

The lac operon is an inducible operon in bacteria that is involved in the metabolism of lactose.

Front

How does the presence of lactose affect the lac operon?

Back

When lactose is present, it acts as an inducer, binding to the repressor and allowing RNA polymerase to transcribe the genes needed for lactose metabolism.

Front

What is a corepressor?

Back

A corepressor is a small molecule that cooperates with a repressor protein to switch an operon off, often by binding to the repressor and enabling it to bind to the operator.

Front

What is the difference between inducible and repressible operons?

Back

Inducible operons are usually off and can be turned on by an inducer, while repressible operons are usually on and can be turned off by a corepressor.