bios1500 ch.11-14

Which of the following base pairs would be targeted and repaired by a mismatch repair system?

A-G

Which of the following is released when an aminoacyl-tRNA synthetase charges a tRNA?

AMP and pryophosphate

All of the following tumor-suppressor genes inhibit cell division EXCEPT

BRCA1.

Which of the following would represent the "transformation principal" first proposed by Griffith through his studies on Streptococcus pneumoniae bacterium?

DNA

All of the following are critical factors for DNA replication on the leading strand EXCEPT?

DNA ligase

Why is the operon arrangement of genes beneficial to certain bacteria?

It allows the coordinated regulation of a group of genes that encode proteins with a common function.

Which of the following statements about RNA polymerase in bacteria is INCORRECT?

It catalyzes the addition of nucleotides to the 5′ end of a growing RNA strand.

Which of the following occurs when the cAMP-CAP complex binds the CAP site near the lac promoter?

RNA polymerase binds to the promoter and transcription rate increases.

Which of the following are points of control for gene expression in eukaryotes?

RNA processing transcription All of the choices are correct. translation post-translational

How many replication forks are there at a replication origin?

2

How many nucleotides are contained in a single codon?

3

Where is the response element found in eukaryotic genes?

50 to 100 base pairs upstream from the transcriptional start site

Which of the following basic features of transcription is NOT shared by both prokaryotes and eukaryotes?

The complexity of protein components involved in transcription is similar for both prokaryotes and eukaryotes.

In the Ames test, mutagenicity is normally tested on a strain of bacterium (Salmonella typhimurium) that cannot synthesize the amino acid histidine. Therefore, these bacteria require histidine in the growth plate to survive. A researcher performs the Ames test to evaluate the mutagenicity of a newly synthesized compound and notices that Salmonella typhimurium is living on a histidine-free growth plate. What can be assumed from these results?

The newly synthesized compound induces a mutation in the bacteria and the bacteria produce histidine.

What is the function of the poly A tail?

The poly A tail increases mRNA stability in eukaryotes.

The lacA gene found within the lac operon encodes for galactosidase transacetylase. This enzyme attaches a(n) ________ group to lactose and lactose analogs.

acetyl

The term N-terminus refers to the presence of a(n) ________ at the 5′ end of a polypeptide.

amino group

What type of regulatory transcription factor binds DNA and increases the transcription of a gene?

an activator exerting positive control

Which of the following could alter the level of expression of a gene?

an increase in salinity presence of a particular energy substrate an increase in environmental temperature All of the choices are correct. exposure to UV radiation

Who discovered that DNA was the genetic material or transforming factor that could convert nonvirulent R-type Streptococcus pneumoniae bacterium to the virulent S-type?

avery, macleod, mccarty

Which of the following is the cancer of epithelial cells?

carcinoma

Which protein directs apoptosis?

caspase

Should a genetic abnormality arise, ________ prevent a cell from progressing uncontrollably through the cell cycle.

checkpoint proteins

The lac operator site within the lac operon is an example of which of the following?

cis-acting element

A eukaryotic gene that is regulated by three activator proteins is said to be under

combinatorial control.

Which of the following proteins is responsible for advancing a cell through the four phases of the cell cycle?

cyclins

The most common eukaryotic ribosome carries out its function in the

cytosol.

A cis-effect is a form of gene regulation that can occur between two DNA segments that are not physically adjacent.

false

As part of the transcriptional unit, regulatory sequences are the sites where RNA polymerase and transcription factors bind to regulate transcription.

false

Different globin polypeptides are expressed at similar levels during the embryonic and fetal stages of mammalian development.

false

MicroRNAs increase the rate of mRNA translation.

false

Studies by Avery, MacLeod, and McCarty with different strains of bacteria and those by Hershey and Chase with T2 bacteriophage determined that proteins are highly complex molecules that form the genetic material for bacteria and viruses.

false

Translation is a relatively slow process.

false

Ionizing radiation can produce which of the following?

free radicals

A(n) ______ is an organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately results in the formation of a functional product.

gene

Which of the following scientist-discoveries is mismatched?

griffith-chromosomes

Which purine base forms 3 hydrogen bonds when binding its complementary nucleotide base?

guanine

The protein of T2 bacteriophage is labeled with 35S and the DNA with 32P. Where would one detect most of the 32P if the T2 bacteriophage were allowed to infect the bacteria?

inside the infected bacteria

This molecule catalyzes covalent bond formation between fragments of DNA.

ligase

A strain of bacteria containing F′ factor genes is called a

merozygote

When cancer cells have the ability to migrate to other parts of the body, they are said to be

metastatic.

Sickle-cell anemia is a human disease that occurs as a result of what type of mutation in the β-globin gene?

missense

Which of the following LEAST belongs with the others?

nucleotide excision repair

___________ are the building blocks of DNA.

nucleotides

A mutation causes a gene to become overactive, contributing to uncontrolled cell growth. Which term best describes this gene?

oncogene

MAPK and MEK are intracellular signaling proteins that mediate cell division induced by growth factors. When mutations in the normal MAPK and MEK genes result in an abnormally high level of MAPK and MEK activity and increases in the rate of cell division, then the mutated gene is called a(n)

oncogene.

Which of the following viruses can cause cancer?

papillomavirus Epstein-Barr virus hepatits B All of the choices are correct. Rous sarcoma virus

The nucleotides within DNA are composed of a

phosphate group, deoxyribose sugar, and nitrogenous base.

In producing a strand of DNA the nucleotides combine to form what type of bond?

phosphodiester

________ is directly produced from the transcription of a eukaryotic gene.

pre-mRNA

Which of the following is NOT a component of the translation machinery?

protein polymerase

A(n) ________ operon is one whose transcription is repressed by effector molecules.

repressible

The mechanism of DNA replication is

semiconservative

Which of the following serves as the "translator" or intermediary between an mRNA codon and an amino acid?

tRNA

Which of the following statements about tRNA is FALSE?

tRNAs can be spliced by splicesomes.

________ attaches DNA sequences at the ends of eukaryotic chromosomes.

telemerase

Which of the following regions of a structural gene contains the information that specifies an amino acid sequence?

transcribed region

Which protein influences the ability of RNA polymerase to transcribe genes?

transcription factors

The process that produces mRNA from DNA is called

translation

A single gene always encodes for an enzyme.

true

Cancers originate from a single cell.

true

DNA is a double helix structure whose strands are held together by hydrogen bonds with A to T and C to G base pairing.

true

Loosely packed chromatin is said to be in an open conformation.

true

More than one codon can specify the same amino acid.

true

Mutations can produce a polypeptide with increased function.

true

Okazaki fragments are sequences of DNA most often found on the lagging strand of DNA during DNA replication.

true

RNA polymerase can bind to the promoter region of the DNA even when the lac repressor is bound to the operator site.

true

The termination of translation occurs when a release factor recognizes the stop codon.

true

Which of the following molecules is a corepressor for the trp operon?

tryptophan

Which of the following types of physical mutagens produces thymine dimer mutations?

ultraviolet light

How many distinct aminoacyl-tRNA synthetases does each cell make?

~20

Myc genes tend to be overexpressed in only a few forms of cancer.

False

What molecule provides the energy for translation?

GTP

All of the following are chemical mutations EXCEPT

X-rays.

Which of the following does NOT occur during transcriptional regulation in eukaryotes?

Chromatin is converted to the closed conformation.

Which of the following is a FALSE statement about the difference in gene regulation between prokaryotes and eukaryotes?

Eukaryotic genes are arranged into operons, while prokaryotic genes are not.

Which of the following is a characteristic of microRNAs (miRNAs)?

MicroRNAs silence the expression of specific mRNAs. MicroRNAs are short RNA molecules. MicroRNAs are cut by an enzyme called dicer. All of the choices are correct. MicroRNAs are found in plants and animals.

Which of the following statements is TRUE of small effector molecules?

Small effector molecules regulate gene transcription by binding a regulatory protein.

What is the function of the general transcription factor TFIID?

TFIID recognizes the TATA box.

Which of the following statements about telomeres is INCORRECT?

Telomeres would predominate more in cells of older than younger individuals.

Which of the following statements about the mRNA start codon is INCORRECT?

The start codon is usually GGA.

Certain types of cancer are caused by viruses.

True

DNA is used as a template to make mRNA, which contains the information to make a polypeptide.

True