Virus (U3) Flashcards
What are parts of a virus?
Nucleic acid, capsid and lipid membrane
What is nucleic acid?
RNA/DNA
Capsid definition?
Protein coat that surrounds DNA/RNA of a virus
Lipid membrane definition?
Membrane around the capsid in many kinds of viruses
- Helps virus enter cells
- ‘Enveloped viruses’, without membrane= naked virus
- Make of lipids, proteins and glycoproteins
What are traits of RNA?
Mutates rapidly, unstable
- Can produces hundreds/thousands of times, mutating easily
- Evolves faster than any other living organism
- Ex. HIV, rabies, influenza
What are traits of DNA?
Don’t mutate, stable
- Typically cause latent infection
- Viral latency
- Ex. warts, chickenpox, mononucleosis
What is viral latency?
Ability of a pathogenic virus to lie dormant (latent) within a cell
What are virus shape? (not on the test)
Helical, polyhedral, binal polyhedral capsid
What is helical? (not on test)
Rod like with capisd proteins winding around the core in a spiral
What is polyhedral? (not on test)
Has many sides, must have 20 sides with 12 corners
What is binal polyhedral capsid? (not on test)
Attached to helical tail
What are the two ways that viruses reproduce?
Lytic and lysogenic
What do bacteriophages/viruses do once they enter lytic cycle?
Once inside a host, destroys cell during reproduction
When do bacteriophages/viruses enter lysogenic cycle?
After lytic, parasitic type of partnership with the cell
What do bacteriophages and viruses attack?
Bacteriophages= bacteria (prokaryotic)
Viruses= attack eukaryotic cells
- Both invade cells and use host cell’s machinery to synthesize more of their own macromolecules
What is the lytic cycle?
Virus enters cell, replicates itself hundreds of times then bursts out of the cell, destroying it
- Virus reproduces itself using host’s machinery
What is the lysogenic cycle?
Virus DNA integrates with host DNA and host’s cell helps create more virus DNA
- Environmental change may cause virus to enter lytic
- Virus reproduces by first injecting its genetic material
How do viruses enter a cell?
Punching a hold in the cell wall and injecting its DNA
How and why do viruses mutate?
Viruses mutate when they copy genetic material
- Copy something wrong
- Mistake proves useful
- More powerful virus (infection)
- Don’t mutate often (exceptions= HIV, influenza)
