AP Biology Operons

Altering patterns of gene expression in prokaryotes would most likely serve the organismʹs survival in which of the following ways?

• allowing the organism to adjust to changes in environmental conditions

• organizing gene expression so that genes are expressed in a given order

• allowing environmental changes to alter the prokaryoteʹs genome

This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA:

• enhancer

• promoter

• repressor

Where does RNA polymerase bind to DNA?

• at an activator site

• on the coding gene sequence

• at a promoter region

• downstream of the coding sequence

• Where the RNA primer is placed

In negatively regulated operon the bound repressor will

• inhibit transcription

• Enhance the activity of RNA polymerase

• Facilitate transcription

• Decrease the enzymatic ectivity of RNA polymerase

Which of these operons is anabolic?

• Lac

• Ara

• Trp

• Phe

Which of these systems give the best mode for turning trp operon off?

• Repressor

• Attenuator

• Repressor with a downstream poly A tail

• Repressor with an attenuator

Tags

NGSS.HS-LS3-2

A Lac repressor is a tetramer repressed when bound to the inducer. The trp repressor is a ____________________

• Dimer inactivated when bound to the inducer

• Dimer activated on inducer binding

• Tetramer inactivated on inducer binding

• Tetramer activated on inducer binding

When uncharged tRNA concentration is low what will you expect as the activity of tryptophan operon?

• Low

• Medium

• High

• Very high

What is the primary function of an operon in prokaryotic cells?

• To regulate gene expression

• To replicate DNA

• To synthesize proteins

• To transport molecules

In the lac operon, what role does the lac repressor play?

• It enhances transcription

• It inhibits transcription

• It facilitates RNA polymerase binding

• It degrades mRNA