Lecture cancer and insect virus quiz Flashcards
Which of the following is thought to be the reservoir for human papilomaviruses?
Both male and female genital tracts.
Cottontail rabbits
Surfaces contaminated with papillomaviruses.
Human male genital tract.
Human female genital tract
Both male and female genital tracts.
Productive infections with human papillomaviruses have been difficult to study in cultured cells. Which of the following explains why?
The viral particles are difficult to purify.
They only infect human cells in culture.
They only produce virions in differentiated keratinocytes.
They induce a strong interferon response in infected cells.
They only produce a few virions per infectious cycle.
They only produce virions in differentiated keratinocytes.
The papillomaviruses used to be classified in the same family as the polyomaviruses. Which of the following is a feature that distinguishes them from polyomaviruses?
Question 3 options:
Their genome is associated with cellular histones in a minichromosome.
They produce proteins that interact with pRb and p53.
Transcription of their genome only occurs on one strand.
Their virion is a naked capsid composed of 72 capsomeres.
Their genome is composed of double-stranded DNA.
Transcription of their genome only occurs on one strand.
Which of the following cellular events causes the papillomavirus to enter “vegetative replication”?
Question 4 options:
Entry into the S phase of the cell cycle.
Terminal differentiation of keratinocytes.
Induction of the apoptosis pathway.
Cell division of the host cell.
Transformation into a cancer cell.
Terminal differentiation of keratinocytes.
Papillomaviruses replicate in differentiated keratinocytes, which are not actively dividing. How does the virus handle this situation?
The viral E6 protein binds to the p53 protein, causing it to be degraded.
Plasmid replication in the basal cells produces enough copies of the viral genome.
The viral E7 protein binds to the pRb protein, forcing the cell into S phase.
The viral E2 protein directly activates transcription of DNA replication genes.
They encode their own DNA replication enzymes.
The viral E7 protein binds to the pRb protein, forcing the cell into S phase.
Cervical tumors caused by human papillomavirus do not show the typical mutations in the p53 gene that most cancer cells have. Which of the following explains why?
Question 6 options:
The E6 protein causes the degradation of the p53 protein.
The virus is not sensitive to the effects of p53.
Cervical epithelial cells do not express p53.
Apoptosis does not occur in cervical epithelium.
The E7 protein binds to pRb, preventing it from inducing apoptosis.
The E6 protein causes the degradation of the p53 protein.
Which of the following describes the mechanism used by the E6 protein of papillomaviruses to remove the p53 protein.
It causes the p53 protein to be targeted to the lysosome.
It causes the p53 protein to become ubiquinated.
It acts as a protease to directly degrade the protein.
It causes the p53 protein to be exported out of the cell.
It phosphorylates p53, which causes it to be degraded by the proteasome.
It causes the p53 protein to become ubiquinated.
The cultured human cell line HeLa expresses the E6 and E7 proteins of human papillomavirus. What would happen to these cells if the expression of these proteins was shut off?
They become even more tumorigenic.
They would continue to grow, just more slowly.
They enter the G0 phase of the cell cycle.
They go into apoptosis and die.
They would continue to grow at their usual pace
They go into apoptosis and die.
Which of the following describes the form that the papillomavirus genome is found in most cervical cancer cells?
A fragment of the genome is integrated into the genome of the host cell.
A fragment of the viral genome remains as an episomal plasmid.
Multiple copies of the genome are arranged in concatamers.
The entire viral genome is integrated into the genome of the host cell.
The intact viral genome remains an episomal plasmid.
a fragment of the genome is integrated into the genome of the host cell
The E2 protein from papillomaviruses can bind to the viral DNA and to mitotic chromosomes. What purpose might this serve for the virus?
It improves the stability of the viral DNA.
It assists with the replication of the viral chromosome.
It allows the viral DNA to be bound by cellular histones.
It is important for regulating viral gene expression.
It allows the viral DNA to segregate to each daughter cell.
allows the viral DNA to segregate to each daughter cell
A great deal of research has gone into making baculoviruses more pathogenic and deadly to their hosts. Which of the following explains why?
They could be used to kill cancer cells.
They are investigated as germ warfare agents.
They could be used as pesticides to kill insects.
They could be used to destroy weeds and other undesirable plants.
They kill bacteria and could be used as antibiotics.
They could be used as pesticides to kill insects.
Which of the following is an unusual feature of baculovirus infections?
They replicate their DNA genome in the cytoplasm.
They package more than one copy of the genome into a nucleocapsid.
They produce two distinct types of virions.
The virion has two separate envelopes.
The virion contains a tegument layer.
They produce two distinct types of virions.
The budded virions produced during a baculovirus infection are primarily involved in which of the following?
Transmission of the virus between cells within a host
Transmission via eggs laid by an infected female.
Shutting down host defense mechanisms.
Surviving the harsh conditions of the environment.
Transmission between different hosts.
Transmission of the virus between cells within a host
Treatment of baculovirus infected cells with the toxin a-amanitin, which inhibits RNA polymerase II, does not reduce levels of the viral late transcripts. Which of the following explains why?
Baculoviruses use the cellular RNA polymerase III to transcribe their late genes.
Baculoviruses produce such high levels of the late mRNAs that the inhibition does not matter.
Baculoviruses produce their own DNA-dependent RNA polymerase.
Insect cells do not use RNA polymerase II to transcribe their genes.
Baculoviruses produce their own RNA-dependent RNA polymerase.
Baculoviruses produce their own DNA-dependent RNA polymerase.
The homologous repeat sequencs (hrs) found in the genome of baculoviruses are involved in which of the following viral events?
Initiation of DNA replication.
Both transcription and replication.
Processing of mRNAs
Enhancement of transcription.
Translation of mRNAs
Both transcription and replication.
