Chapter 13. Regulation of Gene Expression

Which of the following have roles in transcriptional control of eukaryotic genes?

-Activators -DNA -Repressors -Transcription factors

Which events in mRNA processing lead to the translational control of mRNA transcripts?

-Adding a 5' cap -Adding a long 3' poly-A tail

A certain gene except has the sequence AAGGGTAACGA, the changes to CCGGGTAACGA. What just happened?

A gene mutation

structural genes of an operon ____

Code for an enzyme in a metabolic pathway

Frameshift mutations are usually ____ harmful than/as point mutations.

More

Chemical or physical agent that increases the chance of mutation are called

Mutagens

Environment factors such as radiation and organic chemicals can affect the nucleotide base composition of DNA and are therefore referred to as ____.

Mutagens

Jacob and Monod proposed the ____ model to explain gene regulation in prokaryotes.

Operon

which of the following are probably carcinogenic?

-Aflatoxin -Tobacco smoke -X-rays -Ultaviolet radiation

Which of the following can cause spontaneous mutations?

-Chemical change of a base -Transposon movement -DNA replication

which of the following are activities of posttranscriptional control mechanisms?

-Control of mRNA nuclear export speed -Alternatice mRNA splicing

which of the following are possible consequences of a mutated DNA gene?

-Different protein product -Different genotype -Different phenotype -Different mRNA transcript

select the choice that are true of histone proteins.

-Histones compact DNA -Histones play a role in gene regulation -DNA is would around histone proteins.

Which of the following eukaryotic gene expression controls take place in the cytoplasm?

-Posttranslational control -Translational control

The p53 tumor suppressor gene

-Promotes apoptosis -Is frequently mutated in human cancer -Acts as transcription factor

select the events that take place prior to posttranslational control of gene expression.

-Protein has been synthesized -Protein has become active

What does the protein product of regulator gene do?

-Regulates expression of structural genes -Binds to an operon

repressible operons require which of the following?

-Repressor -Corepressor

DNA repair enzymes

-Seal new DNA into a preexisting DNA stand -Remove damaged DNA -Make a new section o DNA

Select the proteins that are required for the initiation of transcription by RNA polymerase in eukaryotes?

-Transcription activator -Transcription factor

Select the proteins that are required for the initation of transcription by RNA polymerase in eukaryotes?

-Transcription factors -Transcription activator

An operon includes

-a promoter, -an operator -Structural

What is the sequence of events that could cause cancer with a defective transcription factor?

1. A mutation occurs in the gene for transcription factor 2. a transcription factor is translated, but misshapen 3. A misshapen transcription factor cannot bind to gene to initiate transcription 4. A mitosis-repressing protein is missing, when mitosis should stop 5. Cell division continues without check, making a mass of cells.

Place these events in the correct sequences as they would occur during the functioning of the lac operon. Begin with the first at the top of the list.

1. Lactose binds to repressor 2. Repressor unbinds from operatoe 3. RNA polymerase binds to the promoter 4. Enzyme for lactose metabolism are synthesized.

List in sequential order the steps leading to transcription during transcriptional control of eukaryotic genes.

1. Trancription factors bind to promoters 2. Trancription activators bind to enchancers 3. Mediator proteins bind transcription activators to transcription factors 4. RNA polymerase begins transcribing

The structural genes found on the LAC operon function to

Break down lactose

How does the siRNA and its associated enzyme regulate gene expression?

By targeting specific mRNA for breakdown

translational control occurs in the ____ eukaryotic cells

Cytoplasm

The protein complex that not only assists with DNA replication, but also has the ability to repair spontaneous mutations is called ____.

DNA polymerase

The transmission of genetic information outside of the coding sequence of a gene is referred to as ____.

Epigenetic inheritance

which of the following forms of chromatin would take up the most linear space (assuming same number of basses for each)?

Euchromatin

Functional proteins are created from mRNA transcripts containing only:

Exons

transcription ____ can either repress or promote transcription to exhibit eukaryotic gene expression control.

Factors

Mediator proteins in eukaryotes connect transcription ____ to transcription ____.

Factors; activators.

True or False: Researchers are interested in epigenetic inheritance so that affected DNA can be altered by changing the DNA sequence.

False

True or False: The phrase, "once an exon always an exon" is an accurate description of posttranscriptional modification eukaryotes.

False

true or false: Lactose metabolism in E. coli is carried out by one enzyme product of one operon.

False

The DNA forms a shape called a _____ when the activators, enhancers, and mediators comes in contact with the transcription factors.

Hairpin loop

Since it is highly condensed and inaccessible to RNA polymerase, the type of chromatin called ____ is seldom or never transcribed.

Heterochromatin

____ is highly compacted chromatin not accessible for transcription.

Heterochromatin

which of the following is a nucleotide sequence that stimulates mitosis and causes cancer?

Oncogene

Which of the following is the last chance of influencing gene expresion?

Posttranslational control

repressible operon usually

Produce proteins that are used often within the cell

Small RNA is formed when double stranded ____ is cleaved into smaller pieces.

RNA

Which of the following would NOT be present in condensed eukaryotic chromatin?

RNA polymerase

This type of mutation occurs in non-sex cells

Somatic mutation

In cats, the alleles for black and orange coat color are carried on the X chromosome. In female cats heterozgous for black/orange coat color, the coat color is patchy, showing black patches in some places and orange patches in others. What is the best explanation for this coloring?

The random inactivation of one of the two X chromosomes in all cells

Match the type of control on the left with its definition on the right.

Transcriptional Control- First step in gene expression Posttranscriptional Control- Processing of mRNA and how fast mRNA leaves the nucleus. Translation control- Occurs in cytoplasm and affects when translation begins Posttranslation Control- Takes place in the cytoplasm and takes place after protein synthesis

Which of these levels of eukaryotic gene control is the most critical?

Transcriptional control

Which of these levels of eukaryotic gene control occurs at the chromatin structure in the nucleus?

Transcriptional control

True or false: Gene regulation occurs in both prokaryotic cells and eukaryotic cells

True

The fur color pattern of tortoiseshell cats is due to

X inactivation

A carcinogen is a type of mutagen that leads to the leads to the development of ____.

cancer

If a repressor is attached to an operator then transcription ____ occur. Conversely, if a repressor is not attached to an operator then transcription ____ occur.

cannot; can

The DNA and its associated proteins are called ___.

chromatin

The ____ region of eukaryotic DNA acts as a regulatory element through binding with transcription activators

enhancer

The protein products of a certain bacterium depend upon its:

environment

In the Ames test, the (experimental/control) bacteria are exposed to a mutagen and the (experimental/control) bacteria are not. They are both plated on nutrient deficient media to see if grows occurs.

experimental; control

True or false: Bacteria produce the same protein regardless of their environment

false

Barr bodies are normally present in

female mammals

A ____ mutation is caused by the insertion of deletion of one or more bases, causing a change of the mRNA codon-reading sequence.

frameshift

Social status can control ____ expression as can be seen in macaque monkeys where high-ranking females have different genes turned on when compared to lower-ranking females.

gene

Even though the DNA is the same in all of the cells of a multicellular organism, cells will assume different features because they express different ____.

genes

Gene mutations called ____-line mutations occur in sex cells and could be passed to the next generation

germ

nucleosomes in eukaryotic chromatin are composed of ____ proteins

histone

A(n) ____ mutation is caused by some outside influence

induced

An inducible operon is activated by a(n) _____.

inducer

____ operons are usually involved in catabolic pathways that serve to break down nutrients.

inducible

____ are the noncoding regions which are excised before the formation of mRNA.

introns

A mRNA transcript that exits the nuclear pores more slowly would result in the production of ____ gene product that would a more rapidly exiting transcript.

less

genomic imprinting is most often an inherited allele from one parents that is tagged with a ____ group.

methyl

RNA interference occurs when ____ molecules interfere with normal gene expression.

miRNA and siRNA

A gene ____ is a permanent change to the base sequence of DNA.

mutation

Of the 5 levels of eukaryotic gene expression controls, 3 occur in the ____ and 2 occur in the ____.

nucleus; cytoplasm

A cancer-causing gene is called a(n) ____.

oncogene

A ____ mutation results in a difference of one base from the original DNA sequence

point

a mutation that results in one base in the DNA being replaced by a different base is called a

point mutation

Since the CAP proteins, when active, promote the activity of the lac operon, they are said to exhibit ____ control over transcription.

positive

Regulation that controls the way mRNA transcripts are processed in the nucleus called ____ control.

posttranscriptional

Operons are generally involved with ____.

prokaryotic

Prior to transcription in prokaryotes, RNA polymerase binds to the ______ region of an operon.

promoter

enzymes that break down proteins

proteases

gene mutation can change a(n) ____ into an oncogene

proto-oncogene

Female mammals have a(n) ____ amount of protein product from genes located on the X chromosomes compared to the amount of gene product from genes on autosomes.

reduced

Gene ____ controls the expression of genes in a cell.

regulation

A ____ is protein that prevents transciption by blocking the promoter.

repressor

Which of the following is formed from the DNA that is used in Transcription of a protein?

sRNA

gene mutation called ____ mutation occur in body cells and would not be passed to the next generation.

somatic

if a mutation arises during DNA replication, then the mutation would considered a(n) ____ mutation

spontaneous

A base ____ is a type of point mutation where one nucleotide is replaced with another incorrect nucleotide

substitution

Mutation of tumor ____ genes could lead to uncontrolled cell division and a tumor.

suppressor

promoting or repressing eukaryotic transcription is regulated by ____ factors

transcription

which of the following binds directly to the enhancer region of eukaryotic DNA

transcription activator

Because of microRNA's, ____ will be inhibited

translation

What is the sequence of events that take place in the TRP operon when tryptophan is present? Begin with the first event at the top of the list

1. Typtophan binds to the the repressor 2. The repressor becomes activated 3. The repressor binds to the operator 4. Transcription of the trp operon is haltered.