Mastering Biology Chapter 11

A mutation in the operator region of the trp operon can prevent the trp repressor from binding to this operator. When these mutant cells are placed in a solution containing chicken broth, which of the following events would happen?

Tryptophan would bind to the repressor.

Enzyme complexes that break down protein are called _____.

proteasomes

Which of these acts as a second messenger?

cyclic AMP

Which of these is NOT a component of the lac operon?

regulatory gene only

Which of these indicates an enhancer region? "The figure shows the operon. Letters from A to D indicates definite structures. Letter A indicates a region of the DNA which is bound by proteins to activate the transcription of a gene. Letter B indicates a region of DNA that initiates transcription. Letter C indicates an enzyme that produces primary transcript RNA. Letter D indicates different structures which control the rate of transcription."

A

Which of these is responsible for initiating a signal transduction pathway? "The figure shows the plasma membrane of the cell. Letters A through E indicates definite structures. Letter A indicates a particle which is attached to a transmembrane protein labeled B. Letter C indicates a protein which is connected with the cell membrane. Letter D indicates a protein which is located in the cytoplasm near the protein C. Letter E indicates a protein in the cytoplasm of the cell which targets to the nucleus of the cell. "

A

Which of these is a membrane receptor? "The figure shows the plasma membrane of the cell. Letters A through E indicates definite structures. Letter A indicates a particle which is attached to a transmembrane protein labeled B. Letter C indicates a protein which is connected with the cell membrane. Letter D indicates a protein which is located in the cytoplasm near the protein C. Letter E indicates a protein in the cytoplasm of the cell which targets to the nucleus of the cell. "

B

What role does a transcription factor play in a signal transduction pathway?

By binding to DNA is triggers the transcription of a specific gene

Which of these directly bind(s) to the promoter? "The figure shows the operon. Letters from A to D indicates definite structures. Letter A indicates a region of the DNA which is bound by proteins to activate the transcription of a gene. Letter B indicates a region of DNA that initiates transcription. Letter C indicates an enzyme that produces primary transcript RNA. Letter D indicates different structures which control the rate of transcription."

C and D

"Which of these acts as a second messenger? "The figure shows a signal transduction pathway. Letters A through E indicates definite structures. Letter A indicates a particle which can connect with a transmembrane protein. Letter B indicates a structure which passes the signal from the transmembrane protein to a protein labeled C by GTP molecule. The protein labeled C uses the energy of ATP molecule catalysis to transform a molecule labeled D. Molecule D catalyzes the transformation of a protein labeled E."

D

Which of these is a regulatory gene? "The figure shows the lac operon. Letters from A to E indicates definite structures. Letter A indicates a region of DNA that initiates transcription. Letter B indicates three structural genes: lacZ, lacY, and lacA. Letter C indicates an enzyme that produces primary transcript RNA. Letter D indicates the segment of DNA to which a structure labeled E binds in order to regulate the gene expression."

D

The operon model of the regulation of gene expression in bacteria was proposed by _____.

Jacob and Monod

There is a mutation in the operator of the lac operon in a cell such that the lac repressor always stays bound to the operator. If lactose is added to the cell, what will happen?

Lactose will bind to the repressor, and lac enzymes will not be produced.

_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm.

Phospholipase C ... IP3 .... Ca2+

What is the function of a spliceosome?

RNA processing

The nuclear membrane's role in the regulation of gene expression involves _____.

Regulating the transport of mRNA to the cytoplasm

_____ bind(s) to DNA enhancer regions.

activators

A protein kinase activating many other protein kinases is an example of _____.

amplification

In prokaryotes, a group of genes with related functions that are organized and regulated as a group is called __________.

an operon

In eukaryotic cells, several proteins are involved in the process of transcription. This process involves enhancers that are __________.

bound by activators

RNA interference (RNAi) can be used by

cells to prevent infections from double-stranded RNA viruses.

In eukaryotes, gene expression is regulated mostly by _____.

controlling the transcription of genes

Cells become specialized by a process known as _____.

differentiation

Calcium ions that act as second messengers are stored in _____.

endoplasmic reticula

Which of the following does NOT accurately describe the lac operon?

eukaryotic

The regions of noncoding DNA shown below that separate the coding regions within a gene are called __________. "The figure shows transcription and RNA splicing. A DNA molecule has exons labeled 1 to 5, which are alternated by introns. A primary RNA transcript obtained from this DNA template has the same structure, but a cap and tail are added. After the RNA splicing, two m RNA molecules are possible: either the cap, exons 1, 2, 3, 5, and the tail; or the cap, exons 1, 2, 4, 5, and the tail."

introns

Small pieces of RNA that can regulate translation of mRNA are called

microRNA

In this drawing of the lac operon, which molecule is an inactive repressor?

molecule D

In the presence of a regulatory protein the lac operon is _____.

not transcribed

Regulatory proteins bind to _____.

operator

The lac operon in Escherichia coli

prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.

Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____.

protein activation

Which molecules are not required to express a gene in eukaryotic cells?

repressor protein

A signal transduction pathway is initiated when a _____ binds to a receptor.

signal molecule