Bio Ch. 18

The cAMP receptor protein (CRP) is said to be responsible for positive regulation of the lac operon because ________.

CRP bound to the CRP-binding site stimulates the transcription of the lac operon

Which of the following best explains why a neuron and a pancreatic cell isolated from the same individual contain different sets of proteins?

Each cell type contains different regulatory proteins and, therefore, they express different proteins.

A mutation in E. coli results in a molecule known as a "super-repressor" because the operon is permanently repressed. Which of the following describes the most likely effect of the mutation on the repressor protein?

It cannot bind to the inducer.

Which of the following statements about the DNA in one of your brain cells is true?

It is the same as the DNA in one of your liver cells.

Which of the following characterizes BRCA1 and BRCA2 as tumor-suppressor genes?

Their normal products participate in the repair of DNA damage.

Prokaryote's ability to regulate patterns of gene expression most likely promotes the organism's survival by ________.

allowing an organism to adjust to changes in environmental conditions

A researcher introduced many copies of a double-stranded RNA into a culture of mammalian cells and used a fluorescent probe to follow it. She found that the introduced strands separated; one strand degraded and the other single-stranded RNA remained. The remaining strand is able to do which of the following?

bind to complementary regions of target mRNAs

How does breakdown of glucose inhibit transcription of the lac operon?

by reducing the levels of intracellular cAMP

A rise in extracellular glucose results in which of the following changes at the lac operon?

cAMP receptor protein (CRP) detaches from the lac promoter

If a mutation deactivated a regulatory gene of a repressible operon in an E. coli cell which of the following describes the most likely outcome?

continuous transcription of the structural gene controlled by that regulator

If the DNA of a mammalian promoter region experiences increased methylation on cytosine (C) which of the following results is most likely to occur?

inactivation of the gene

Cell differentiation always involves ________.

the production of tissue-specific proteins

Within a cell, the amount of protein made using a given mRNA molecule in that cell depends partly on ________.

the rate at which the mRNA is degraded