Operons

what is an operon?

• a part of a ribsome
• a part of a Rna
• a unit made up of linked genes that code for proteins needed to do a specific task
• needed for dna replication

A protein that binds to the operator and blocks the RNA polymerase

• regulator
• repressor
• activator
• corepressor

The "on/off" switch for an operon is called the

• promoter
• repressor
• operator
• gene

What is the name of the stretch of DNA where RNA polymerase binds?

• operator
• promoter
• enhancer
• origin

In the lac operon model the genes within the operon will be expressed if:

• lactose is absent in the cell
• glucose is present in the cell
• lactose is present in the cell

What type of operon is the trp (tryptophan) operon?

• inducible
• repressible
• positive control
• promoible

Operons are found in the cells of which of the following types of organisms?

• prokaryotes (bacteria)
• eukaryotes (plant and animals)
• animals only
• viruses

For a repressible operon to be transcribed, which of the following must be true?

• A corepressor must be present.
• RNA polymerase and the active repressor must be present.
• RNA polymerase must bind to the promoter, and the repressor must be inactive.
• RNA polymerase cannot be present, and the repressor must be inactive.

Which of the following describes an operon that is inactive and becomes activated by a molecule binding to the repressor?

• inducible operon

• repressible operon

Which of the following describes an operon that is active and becomes inactivated by a molecule binding to the repressor?

• inducible operon

• repressible operon