Virus Lecture 18 Flashcards
After entry the infectivity of the virus particles disappear, this is called?
Eclipse
What causes the eclipse?
The uncoating of the virus particles.
What happens during the latent period?
Replication of viral nucleic acid and protein occurs and there is no sign of significant infection.
When a virus nucleic acid and protein are assembled to mature virus particles is called?
Maturation period
Where are the attachment site for animal viruses?
All over the surface
What are the virus receptors of the cell made of?
Protein and glycoprotein
T:F Receptor sites are host specific and varies between virus groups.
True
Also varies between person to person
Virus entry is receptor mediated through?
Endocytosis
Fusion is?
The means by which enveloped viruses enter cell.
The removal of capsid protein and release of nucleic acid is known as?
Uncoating
When does uncoating happen?
During the eclipse period
What are needed for uncoating?
Lysosomal enzymes and host cell enzymes
What large virus has its own uncoating enzymes?
Pox virus
Active viremia is?
Viremia following virus replication in the host
Viremia is?
The presence of virus in the blood
The direct inoculation of virus in host, such as contaminated syringe or bite of arthropods is known as?
Passive Viremia
T:F Replication happens in passive viremia.
False
No replication happens at site/port of entry
What are the effects of virus infections?
Transformation of normal cells to tumor cells
Lytic infection
Persistent infection
Latent infection
Mechanisms of viral injury and disease:
Inhibition of host-cell nucleic acid synthesis
Inhibition of host-cell RNA transcription
Inhibition of host-cell protein synthesis
Cytopathic effect of “toxic” viral proteins interference with cellular membrane
Neoplastic transformation
Drive host cell to apoptosis (cell suicide)
Non-cytocidal changes (persistent infection)
What is a provirus?
A virus genome that is integrated to the DNA of a host cell.
What is a prophage?
In the case of bacteriophages, virus genome that is integrated into the DNA of a host cell (bacteria).
What are retroviruses?
A family of enveloped viruses that are single stranded RNA and use reverse transcription to replicate.
What is the difference between primary cell lines and diploid cell lines?
Primary cell lines are derived from tissues and die after a few generations
Diploid cell lines are developed from human embryos and can grow for 100 generations
What are continuous cell lines?
Are transformed (cancerous) immortal cell lines
PCR testing for RNA viruses what do you need in addition to the regular PCR components?
Reverse transcriptase
