Viruses

Which of the following nucleic acids make(s) up viral genomes?

DNA or RNA

Which of these is the viral genome?

E

Why is combination drug therapy for HIV/AIDS less likely to lead to resistance than single drug therapy?

The likelihood of one virus spontaneously mutating to be resistant to several different drugs at the same time is extremely small.

Which of the following statements correctly describes the lysogenic cycle of lambda (λλ) phage?

The phage genome replicates along with the host genome.

Which of these binds to receptor molecules on the host cell membrane?

A

Which of the following statements correctly describes one characteristic of the lytic cycle of viral replication?

A large number of phages are released at a time.

Which of the following events stimulates the production of viral particles in a host cell?

Activation of the host cell by cytokines, growth factors, or antigens.

You are an epidemiologist working on a vaccine for COVID-19. Which of the following would be helpful to analyze, as it is also a coronavirus?

Both SARS and MERS Submit

Which of these is reverse transcriptase?

C

Which of the following diseases is most similar to COVID-19 in its origin and spread to humans?

Ebola, in which bats were the likely wild host, and now spreads from human to human. Submit

How does HIV cause disease?

HIV kills cells that defend the body against disease.

What is the function of reverse transcriptase?

It catalyzes the formation of DNA from an RNA template.

What is the function of reverse transcriptase in retroviruses?

It uses viral RNA as a template for DNA synthesis.

Per CDC recommendations, you wear a mask to reduce transmission of COVID-19. Which of the following is the best way to wear it?

Over your mouth and nose, as it is transmitted by coughing or sneezing.

Why do RNA viruses tend to have unusually high rates of mutation?

Replication of their genomes does not involve correcting errors in genome replication.

How does HIV bind to a host cell?

The viral envelope proteins interact with CD4 and a co-receptor on the cell membrane.

Which of the following responses correctly lists the order of events in a generalized viral replicative cycle?

The virus enters the cell, host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA.

Which of the following statements about viruses is FALSE?

The widespread use of antibiotics has led to resistant strains of viruses.

Which of the following statements accurately describes plant virus infections?

They are spread via the plasmodesmata.

Which of the following statements correctly describes adenoviruses?

They contain DNA surrounded by a capsid. Submit

How do enveloped viruses differ from nonenveloped viruses?

They have a membrane-like outer covering.

How do antiviral drugs help to treat viral infections?

They interfere with viral replication.

Which of the following can be found in bacteria, but not viruses?

a cell membrane

Suppose you were in charge of sending an unmanned space probe to a new planet in search of life. The probe would be able to collect and test samples and make observations, but the planet is too far away for the probe to be able to bring samples back to Earth. The probe is small and would only be able to run a few tests, so you want to pick a test for evidence of life that is broad enough to incorporate all forms of life as we know it. Which one of the following tests would be the best to use in this situation?

a test for the presence of cells that contain DNA

Which of the following statements correctly describes the best predictor of how much damage a virus causes?

ability of the infected cell to undergo normal cell division

Homeostasis is a living organism's

ability to maintain constant internal conditions even when environmental conditions change.

Which of the three types of viruses shown in the figure above would you expect to include a capsid(s) as part of their overall structure?

all three

Which enzyme inserts viral DNA into the host's chromosomal DNA?

integrase

You are a doctor treating patients with COVID-19. A patient is suffering a cytokine storm. Which of the following will you need to treat?

congestion and inflammation of the lungs

Some people who have had a herpesvirus-mediated cold sore or genital sore may have flare-ups for the rest of their life. Why does this occur?

copies of the herpesvirus genome remaining as mini-chromosomes in some host cell nuclei

Which of the following is NOT a characteristic of living things?

creating energy

True or false? The human immunodeficiency virus (HIV) uses reverse transcriptase to make double-stranded RNA copies of its DNA genome.

false

The pointer is indicating the virus's _____.

genome

Which of the following processes can be effective in preventing the onset of viral infection in humans?

getting vaccinated

In the figure above, at the arrow marked II, what enzyme is being utilized?

host cell DNA polymerase

What is the source of a viral envelope?

host cell membrane

An effective vaccine for COVID-19 is created by altering Ace-2 receptors. These are most important in which part of the body?

larynx

Which replicative cycle describes a virus that can integrate its genome into the host cell's genome?

lysogenic

Cycle A is the _____ cycle and cycle B is the _____ cycle.

lytic ... lysogenic

Viruses are

not alive because they are not made of cells and require a host cell for reproduction.

Double-stranded viral DNA is incorporated into a host cell as a _____.

provirus

Which viruses have single-stranded RNA that acts as a template for DNA synthesis?

retroviruses

What enzyme allows a retrovirus to make DNA from an RNA template?

reverse transcriptase

The lytic cycle of bacteriophage infection ends with the _____.

rupture of the bacterium

The genetic material of HIV consists of _____.

single stranded RNA

As a result of the lytic cycle, _____.

the host cell's DNA is destroyed

Which of the following characteristics determine a virus's host range?

the proteins on its surface and that of the host

Viral DNA makes mRNA by the process of _____.

transcription

In the lysogenic cycle _____.

viral DNA is replicated along with host DNA Submit

The pointer is indicating the _____.

viral protein coat