Gene Regulation and Operons

Front

What is a promoter?

Back

A DNA segment that allows a gene to be transcribed and helps RNA polymerase find where a gene starts.

Front

What is an operator?

Back

A DNA segment that turns a gene 'on' or 'off' and interacts with proteins that regulate transcription.

Front

What is an operon?

Back

A region of DNA that includes a promoter, an operator, and one or more structural genes that code for proteins needed for a specific task.

Front

In which organisms are operons most often found?

Back

Operons are most often found in prokaryotes and roundworms.

Front

What is the lac operon?

Back

One of the earliest examples of gene regulation discovered in bacteria, consisting of three genes that code for enzymes to break down lactose.

Front

What happens to the lac operon without lactose?

Back

RNA polymerase is blocked, preventing transcription of genes for enzymes that digest lactose.

Front

What happens to the lac operon with lactose present?

Back

RNA polymerase transcribes the genes for enzymes that digest lactose.

Front

What role does the repressor play in the lac operon?

Back

The repressor blocks RNA polymerase from transcribing the genes when lactose is not present.