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47 Cards in this Set

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  • Back
simplest organism on earth; considered living because they replicate but non-living because replication isn't independent.
Virus (Ch. 10)
How many genes can viruses have?
2-50 genes
Required for viruses to propagate new virions.
host factory
complete virus particle
bacterial viruses that cause holes in bacteria in a petre dish by killing the bacteria
nucleic acid + protein coat
How are viruses grouped?
By size and shape, naked or enveloped, and DNA or RNA.
Term meaning to break open a cell
Viruses with potential to become lytic
lysogen aka provirus
Name the stages of the viral life cycle
1. attachment
2. penetration
3. uncoating
4. nucleic acid replication
5. protein sythesis
6. self assembly
7. Release
A surface protein of a virion with a specific attachment site
How does naked virus penetration occur?
Step in the viral life cycle where host's enzymes uncoat nucleocapsid, releasing viral nucleic acid inside of host cell.
How are enveloped viruses uncoated?
lysosomal enzymes
How are naked viruses uncoated?
cytoplasmic proteins
In what part of host cell does DNA virus replication occur?
host nucleus, where host DNA synthesis occurs
What is required for DNA virus replication?
At least one protein for replication to subvert host replication enzymes to from replicating host DNA to replicating virus DNA.
In what part of host cell does RNA virus replication occur?
host cell cytoplasm
Why must RNA viruses code for their own RNA polymerase?
Host cell lacks enzymes that will recognize the virus RNA template.
When is the only time an infected host cell is not converted for exclusive replication of the virus?
In the case of tumor viruses
In what part of the host cell does viral protein synthesis take place?
host cytoplasm (where translation occurs)
Step of the viral life cycle that occurs like magnets d/t natural binding sites
self assembly
How are naked viruses released from host cell?
They lyse the host cell
How are enveloped viruses released from the host cell?
They bud through the host cell membrane, acquiring a coat that becomes their envelope.
The process by which a virion attaches to a host cell.
The protein coat surrounding the nucleic acid genome inside a virus.
The protein subunit of a capsid.
Changes in human cells caused by viral infection.
cytopathic effects
Microscopically observable dark areas of virus particles.
inclusion bodies
Organisms incapable of growing outside of a host cell.
obligate intracellular parasites
Twenty identical sides
The nucleic acid in a virion is either ,________or ______ but not both
Spongiform encephalopathy in humans
Creutzfeldt-Jacob disease
Another name for spongiform encephalopathy in humans
The smallest known replicating agents; they do not have DNA,RNA, or nucleic acids.
Spongiform encephalopathy in sheep.
How does enveloped virus penetration occur?
membrane fusion
An area of no living cells
CPE in which cells are killed in a virus growth area resulting in plaques
cell killing
How are the number of viruses quantified using cell killing?
by counting the number of plaque
CPE in which host cells no longer adhere tightly to the bottom of the tissue cx dish.
round up
CPE in which there is an accumulation of observable dark areas of virus particles
inclusion bodies
CPE in which viruses cause cells to join together into giant cells
syncytia formation
CPE in which tumor viruses cause cells to keep growing until piles of cells are visible in dish.
Viruses that carry out transcription in reverse, using an RNA template to make a DNA copy
An enzyme that uses viral RNA as a template to produce a duplex DNA copy that is integrated into host chromosome where virus is then expressed.
reverse transcriptase (RT)
Name the only two types of viruses that are associated with cancer
DNA viruses and retroviruses