Chapter 5, 6, 7 test 2 review questions

During DNA replication, which enzyme is involved in proofreading to prevent the incorrect matching of nucleotides?

DNA polymerase

Which enzyme is the main contributor to the development of spontaneous mutations?

DNA polymerase II

In DNA replication, what is the main enzyme responsible for adding complementary nucleotides to the daughter strand while reading the parent strand?

DNA polymerase III

All of the following explain why viral genomes evolve rapidly except:

DNA viruses have a high mutation rate. Although mutations occur in DNA viruses, they do not mutate as rapidly as RNA viruses.

The term "redundancy" in molecular biology refers to?

Different codons that code for the same amino acid

Viral genetic reassortment is most likely to occur when

Different viral strains infect the same cell Viral genetic reassortment occurs when related viral strains co-infect the same cell and their genomes mix.

All of the following viruses exhibit narrow tropism except

Ebola virus The Ebola virus exhibits broad tropism and can infect a wide range of host cells or tissues.

Which is the most effective method for culturing viruses used in the development of the influenza and mumps vaccine?

Embryonated eggs Embryonated eggs are used to grow the influenza virus, the mumps virus, and other viruses.

The viral __________ is often comprised of the host cell membrane.

Envelope Some animal viruses have lipid-based envelopes that surround the capsid that is derived from the host cell as the virus buds from the host.

Which of the following viruses and cancer links are mismatched?

Epstein-Barr virus: adult T-cell leukemia. You chose the mismatched pair. The Epstein-Barr virus is associated with B- and T-cell lymphomas and Hodgkin's disease, while human T-lymphotrophic viruses (HTLVs) cause adult T-cell leukemia.

In DNA replication, protein factors are more heavily required for replication in?

Eukaryotic cells

The process of removing incorrect nucleotides and replacing them with correct ones is referred to as?

Excision repair

Host antibodies against the influenza virus are developed against

HA and NA spikes The host immune system recognizes HA spikes on the surface of the influenza virus.

Which of the following is the family name for the HHV-1 virus?

Herpesviridae The family name for viruses is always italicized, with the first letter capitalized and always ending in -viridae.

Which of the following DNA virus families includes viruses that cause oral herpes, genital herpes, and chickenpox?

Herpesviridae Viruses in the Herpesviridae family cause oral and genital herpes and chickenpox.

The Ames test is used to identify if a chemical will result in mutations. This test uses the microorganism S. typhimurium and the amino acid?

Histidine

The process of transferring of genetic information between cells in the same generation is referred to as __________.

Horizontal gene transfer

Which of the following is the species name of HHV-1?

Human herpesvirus-1 or Herpes simplex virus 1. The species name of a virus is always italicized, the first name and proper names are always capitalized, and it should not be abbreviated.

Which of the following viruses causes a chronic infection?

Human immunodeficiency virus HIV, which impacts the immune system by killing T-cells, follows this slow progressing chronic model.

Which of the following is oncogenic?

Human papilloma viruses There are over 200 different types of HPVs, about a dozen of which have been linked

In eukaryotic mRNA, there are sequences of mRNA that do NOT encode for specific amino acids and do NOT contribute to the protein. These sequences are called?

Introns

Of the following statements, which does NOT apply to a microorganism that has a fertility plasmid?

It can undergo vertical gene transfer.

A virus that can only infect humans would best be described as having a

Narrow host range The host range is the collection of hosts a virus can infect. Some viruses can infect more than one species, while other viruses can only infect one species.

Where is the chromosomal DNA found in prokaryotic cells?

Nucleoid

Which of the following is the highest taxon for viruses?

Order The order level is the highest taxon for viruses.

Which of the following RNA virus families includes the virus that causes influenza?

Orthomyxoviridae The Orthomyxoviridae virus family includes the virus that causes influenza.

Which of the following DNA virus families includes the viruses that cause warts and cervical cancer in humans?

Papillomaviridae Viruses in the Papillomaviridae family cause warts, and some strains cause cervical cancer.

Riboswitches are best defined as?

Parts of mRNA that are not translated and act as post-transcription regulators

Which of the following does not describe naked animal virus replication?

Penetration through membrane fusion Enveloped viruses penetrate the cell through membrane fusion.

After a lytic bacteriophage attaches to a bacterium, what is the correct order of the next steps in the lytic replication cycle?

Penetration, replication, assembly, release This is the order of the steps in the lytic replication cycle.

Which of the following is the correct sequence of animal virus replication after attachment?

Penetration, uncoating, replication, assembly, release This is the correct sequence of animal virus replication.

The following are concepts that relate to animal viruses. Choose the mismatched pairing.

Penetration: genetic material injected into the cell You chose the mismatched pair. Bacteriophage inject genetic material into the bacterial cell during the penetration step, but animal viruses do not.

Prophages sometimes provide bacteria with genes that encode pathogenicity factors through a process called

Phage conversion Phage conversion can provide bacteria with the capacity to make certain toxins or other pathogenicity factors.

Which functional group is found at the 5' end of DNA?

Phosphate group

Which of the following RNA virus families includes the virus that causes polio?

Picornaviridae The Picornaviridae family includes viruses that cause polio, hepatitis A, and the common cold.

Which type of genetic material may be found in both prokaryotic and eukaryotic cells and may contain genes conferring antibiotic resistance?

Plasmids

Which of the following statements is NOT a characteristic of plasmids?

Plasmids are part of the cell's chromosome.

To start DNA replication, the origin of replication is recognized by a collection of factors called the

Primosome

One major difference between prokaryotic and eukaryotic translation is?

Prokaryotic translation is polycistronic, and eukaryotic translation is almost always monocistronic.

Primase lays down a short piece of __________ as a primer to start DNA replication.

RNA

What is the main enzyme required for transcription of a gene?

RNA polymerase

The role of transcription factors is to signal?

RNA polymerase to the promoter region of the intended gene to be transcribed.

RNA viruses are able to mutate more rapidly than DNA viruses because

RNA polymerases do not have proofreading capabilities RNA polymerases, which copy RNA, do not have the proofreading capabilities of DNA polymerases.

The term used by molecular biologists to describe the flow of genetic information from DNA to RNA to protein is?

The central dogma of biology

Viral tropism describes

The tissues or cells a virus can infect Viral specificity to tissues or the cells they infect is due to virus surface factors being able to bind to specific surface molecules on certain host cells.

Which of the following viral features does not contribute to their classification as nonliving?

Their extremely small size.

Which of the following would be considered a FALSE statement about small noncoding RNAs?

They are found only in prokaryotic cells.

Of the following statements, which one is NOT related to transposable elements?

They create a stable, nonchanging genome.

Which of the following best describes the genomes of influenza, measles, Ebola, and rabies viruses?

They each have an RNA genome that is complementary to mRNA. These viruses all have genomes that are complementary to mRNA and must be transcribed into a readable mRNA format by RNA-dependent RNA polymerases before translation.

Choose the false statement about oncoviruses.

They stimulate cells to undergo apoptosis. You found the false statement. Oncogenic viruses often decrease cell responsiveness to apoptosis signals.

UV radiation can result in __________ in a cell's DNA.

Thymine dimers

Griffith's experiment proved that bacteria can take up naked DNA from the environment and use it as part of their genome. This process, which can occur in a laboratory or in a natural setting, is called __________.

Transformation

A codon consists of __________ nucleotides.

Two Two nucleotides are too short and will not match up with the anticodon on the tRNA.

Which of the following nucleotides is found only in RNA and not in DNA?

Uracil

Retroviruses produce mRNA by:

Using reverse transcriptase to convert single- stranded RNA (ssRNA) to double-stranded DNA (dsDNA) and then using the dsDNA for transcription. Retroviruses use their single-stranded RNA genome to direct formation of DNA using reverse transcriptase.

A __________ is a single particle made up of genetic material encased in a protein shell.

Virion A virion is a single virus particle comprised of an exterior protein capsid packed with genetic material.

Which of the following is not used to classify and name viruses?

Virus size Virus size is not used by the ICTV to name and classify viruses.

Which of the following is mismatched?

Viruses: Replication through mitosis. You found the mismatched pair. Viruses use host-cell energy and machinery to replicate.

Which of the following is mismatched?

Viruses: Usually viewed with light microscopy. You chose the mismatched pair. Most viruses can only be viewed with electron microscopy.

Proteins provide cells with the necessary equipment to perform normal cellular activity. Without gene expression the cell?

Would die

In __________ viral infections, there is a continuous release of virions over time and a slow progression of disease.

chronic Chronic persistent infections are characterized by a continuous release of virions over time, and in some cases, a period of quiet infection.

Stress such as fever, sunburn, or hormone level changes can trigger the reactivation of a _________ viral infection.

latent Latent infections are distinguished by flare-ups with intermittent periods of dormancy.

Lytic bacteriophages use the enzyme __________ to break down host cell walls that allow the release of newly formed bacteriophage.

lysozyme Lysozyme breaks down host cell walls and causes bacterial cell lysis once the newly assembled phages are assembled.

An anticodon is found on?

tRNA

Quorum sensing allows bacteria within communities to communicate with chemical messages, which may help regulate gene expression. The chemical messages are called?

Autoinducers

RNA primers are removed from the leading and lagging strand by

DNA polymerase I

Which of the following RNA virus families includes the virus that causes dengue fever?

Flaviviridae at's correct.Viruses in the Flaviviridae family cause hepatitis C, West Nile encephalitis, and dengue fever.

Which of the following mutations is the most detrimental to the cell?

Frameshift mutation

The genetic makeup of an organism is its

Genotype

Which of the following word pairs describing chronic and latent viral infections is mismatched?

Latent infections: run their course and are cleared by the host immune system You found the mismatched pair. The description used here best describes acute viral infections, not latent infections.

Which of the following terms about bacteriophage replication is mismatched?

Lytic replication: phage conversion You chose the mismatched pair. Phage conversion does not occur in the lytic cycle of bacteriophage replication.

Which of the following most accurately describes icosahedral viruses?

May appear spherical, but are three-dimensional polygons Icosahedral viruses look like three-dimensional polygons, but they may appear spherical.

Antigenic drift results from:

Minor changes to HA and NA spikes resulting from frequent mutation of the influenza RNA genome. Influenza's RNA genome mutates frequently, so minor changes to HA and NA frequently occurs.

Which of the following does not describe enveloped virus replication?

Release through host cell rupture Naked viruses are released through host cell rupture.

cDNA is a product of the action of?

Reverse transcriptase

RNA nucleotides are made of a sugar, a phosphate, and a nitrogen base. Which sugar is unique to RNA nucleotides and is NOT found in DNA nucleotides?

Ribose

Which of the following is not a viral genome arrangement?

Segmented DNA To date, there is no evidence of a segmented DNA genome in viruses.

There are two nonstandard encoding amino acids:

Selenocysteine and pyrrolysine

Choose the false statement.

Single-stranded DNA (ssDNA) viruses use RNA-dependent RNA polymerases to build mRNA. You found the false statement. Certain RNA viruses use RNA-dependent RNA polymerases, not DNA viruses.

Transduction that involves a temperate phage integrating into the host cell genome is called?

Specialized transduction

Frequent mutations in Influenza A change the protein makeup of hemagglutinin (HA) and neuraminidase (NA) __________.

Spikes Influenza viruses mutate frequently and experience small changes in HA and NA spike proteins.

Viral __________ help viruses attach to and gain entry into host cells.

Spikes Viral spikes are glycoprotein extensions that help viruses attach to and gain entry into host cells.

Which of the following bacterial pathogenicity factors is not the result of phage conversion?

Tetanus toxin The tetanus toxin produced by Clostridium tetani is not the result of phage conversion.

Which type of RNA carries in amino acids and adds the amino acids to the "A" site in the ribosome?

tRNA

In DNA replication, Okazaki fragments are required in synthesizing

the lagging strand, because the DNA polymerase can move only in the 5' to 3' direction

Which of the following is considered a pre-transcriptional regulation and NOT a post-transcriptional regulation?

A repressed operon

In an inducible operon, what protein is used to turn off transcription by binding to the operator sequence?

A repressor protein

A transposon that relies on an RNA intermediate is called?

A retrotransposon

After translation, protein modifications are necessary for a final functioning product. Which of the following is NOT part of protein modification?

Addition of a methionine

Yearly vaccinations for influenza are necessary due to

Antigenic drift Antigenic drift is the result of minor mutations to HA and NA spikes that allow the virus to evade a quick antibody response by making the new strains different enough to go unrecognized by the immune system, which necessitates yearly vaccinations against new strains.

Pandemic outbreaks of influenza are the result of

Antigenic shift Antigenic shift often leads to viral strains with new features, such as increased infectivity or expanded host range, which can set the stage for worldwide pandemics of influenza.

Which of the following steps is not part of lysogenic replication?

Assembly You chose the step that is not part of lysogenic replication. Lysogenic bacteriophages do not undergo assembly.

Which is the most effective method for culturing bacteriophages?

Bacterial culture on solid agar or in liquid broth Bacteriophages are most effectively grown in a bacterial culture. Either a culture on solid agar or in liquid broth is effective.

The avian influenza virus host range includes all of the following except

Cattle The avian influenza virus does not affect cattle or other ruminants.

Which of the following word pairs describing chronic and latent viral infections is mismatched?

Chronic infections: distinguished by flare-ups triggered by stress You found the mismatched pair. Chronic infections are characterized by a slow progression of disease.

Which of the following is not a viral genome arrangement?

Circular RNA RNA viral genomes can be linear or segmented, single or double stranded, but not circular.

If a cell is to be transformed in a lab, the cell must be __________ to uptake the available genetic information.

Competent

The exchange of genetic information by use of a pilus and cell-to-cell interaction is called?

Conjugation

During optimum conditions, E. coli will replicate every 20 minutes. Because the genes required for replication are needed as part of a routine function, these genes are considered?

Constitutive genes

Which of the following RNA virus families includes the virus that causes severe acute respiratory syndrome (SARS)?

Coronaviridae The Coronaviridae family includes viruses that cause SARS and the common cold.