Bio: viruses

Terms in this set (45)

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
Genetic material composed of nucleic acid.
Emerging viruses arise by:
The spread of existing viruses more widely within their host species, mutation of existing viruses, and the spread of existing viruses to new host species.
To cause a human pandemic, the H5N1 avian flu virus would have to:
Become capable of human-to-human transmission.
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have:
T4 protein and T4 DNA
RNA viruses require their own supply of certain enzymes because
Host cells lack enzymes that can replicate the viral genome
How do prions, which are misfolded proteins, infect organisms?
Prions enter brain cells and cause normal forms of the protein to refold into the prion form.
The H1N1 2009 outbreak is considered to have been which of the following?
A pandemic.
A plant that has been raised in a sterile environment shows symptoms of a viral infection. How would you explain this?
The viral infection was acquired by vertical transmission.
What is the most effective way to stop viral infections?
Vaccines.
What happens first when a phage infects a bacterial cell and is going to enter a lysogenic cycle?
Linear DNA circularizes.
HIV uses which of the following processes to synthesice a DNA strand using its RNA genome as a template?
Reverse transcription.
Why are retroviruses considered a special class of viruses?
They transcribe RNA to DNA uing reverse transcriptase.
Why are viruses called obligate intracellular parasites?
They must use a host cell's amino acids to synthesize proteins;
They must use a host cell's ribosomes to synthesize proteins;
They must use a host cell's nucleotides for transcription and replication;
They must use a host cell's metabolic enzymes and pathways to obtain energy;
Why is it ineffective to treat viral disease with antibiotics?
Antibiotics inhibit enzymes specific to bacteria and have no effect on virally encoded enzymes.
True or false? The human immunodefiency virus (HIV) uses reverse transcriptase to make double stranded RNA copies of its DNA genome.
False.
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
How does HIV bind to a host cell?
The viral envelope proteins interact with CD4 and a co-receptor on the cell membrane.
Which enzyme inserts viral DNA?
Integrase.
Which replicative cycle describes a virus that can integrate its genome into the host cell?
Lysogenic.
How do enveloped viruses differ from nonenveloped viruses?
They have a membrane-like outer covering.
How does HIV cause disease?
HIV kills cells that defend the body against disease.
Double-stranded viral DNA is incorporated into a host cell as a_____.
Provirus.
What is the source of a viral envelope?
Host cell membrane.
What is the function of reverse transcriptase?
It catalyzes the formation of DNA from an RNA template.
The genetic material of HIV consists of______.
Single stranded RNA.
In the lysogenic cycle_______.
Viral DNA is replicated along with host DNA.
As a result of the lytic cycle_____.
The host cell's DNA is destroyed.
Viral DNA makes mRNA by the process of _____.
Transcription
The lytic cycle of bacteriophage infection ends with the____.
Rupture of the bacterium.
Which statements about viruses are true?
A retrovirus contain both DNA and RNA;
The capsid enters the host cell if the virus is enveloped;
Enveloped viruses bud from the host cell;
HIV contains reverse transcriptase;
All of the statements below are true. Select the statement that best supports the view of most biologists that viruses are nonliving.
An isolated virus is unable to replicate its genes or regenerate ATP.
How does a virus differ from a bacterium?
Viruses, unlike bacteria, lack metabolic enzymes.
Identify all correct statements about how viroids differ from viruses.
Unlike viruses, viroids do not encode proteins.
Where do retroviruses carry their genetic material?
RNA
HIV evolved from a virus that infected what species?
Chimpanzee
Which of the following is true?
The borna virus only targets mammals and birds.
Your dog is lacking syncytin. It will not be able to properly form what?
A placenta
How do prions differ from viruses?
Unlike a virus, a prion is a single molecule;
Unlike viruses, prions do not include any nucleic acids;
Unlike viruses, prions are infectious proteins;
Approximately how many people worldwide are infected with AIDS?
60 Million
You are an epidemiologist studying a new disease very similar to AIDS. Most likely, this new disease is caused by what?
A retrovirus
Which of the following is true?
Kaposi's sarcoma is a symptom of AIDS.
AIDS can be contracted by contact with which of the following?
Blood or semen
How long must AIDS patients take their medication?
For the rest of their life.
The nucleic acid of a virus particle is enclosed in a protein coat. What is it called?
Capsid
What do we call a virus that attacks a bacterium?
Phage.
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