smartbook 7

Unregulated genes have ______

constant levels of expression.

A benefit of gene regulation is that encoded proteins will not be produced when they are not needed.

true

What type of genes encode proteins the bacterial cell needs all the time?

Constitutive genes

Genetic control of the production of specific proteins at specific times would occur in which of the following situations?

Producing enzymes to metabolize specific sugars when those sugars are found in the environment When bacterial cells are getting ready to divide When bacteria are subject to heat stress

A regulatory protein that increases the rate of transcription is a(n) ___

activator

Constitutive genes ______.

are unregulated.

Examples of a(n) ___ stress that might require a bacterium to produce a specific protein include osmotic shock or heat shock.

environmental

Effector molecules influence gene expression by binding to DNA.

false

Transcription regulation by an activator protein is considered to be ______ control.

positive

A benefit of gene regulation is that encoded proteins are not made when they are not needed. This ______.

prevents the cell from wasting energy

The phenomenon in which the level of gene expression can vary under different conditions is gene

regulation

The binding of a small effector molecule to a regulatory protein changes the ___ of the regulatory protein, which alters its DNA-binding ability.

conformation

Gene expression is always the same.

false

Gene regulation is constant.

false

The rate of transcription initiation rarely influences overall gene expression.

false

Constitutive genes encode proteins the cell needs ______.

all the time

Unregulated genes are also called ___ genes

constitutive

A protein such as a repressor that inhibits transcription is exerting ___ control of transcription.

negative

Certain proteins help a bacterium survive environmental stress such as heat shock. These proteins are required ______.

only when confronted with the stress

In bacteria, the most common way to regulate gene expression is by influencing ______.

the rate of transcription initiation

An inducer could bind to a(n) ______ and prevent it from binding to the DNA, or it could bind to a(n) ______ and cause it to bind to the DNA.

repressor; activator

Control of gene expression leads to the production of specific proteins to assist bacterial cells in responses to environmental stressors, preparation for cell division, and ______.

metabolism