Viruses Flashcards
Characteristics of a virus
- relies on a host to replicate
- non living/ acellular
- very small
Viruses possess a _____ shell/ coating that contains _____ ______
Protein, Nucleic Acids
A viral particle (virion) contains
- DNA/RNA
- Protein coat
- carbohydrates and lipids (sometimes)
Different structures of viruses
- Helical
- Polyhedral
- Spherecal
- complex
Describe helical shaped viruses
shaped like a cylinder (helical) with a hollow center
Describe polyhedral shaped viruses
they have multiple faces that take on different shapes (ex. triangles)
Describe sphereical shaped viruses
enveloped spheres that contain DNA/RNA which are wrapped in a phospholipid bilayer
Describe complex shaped viruses
comprised of any other shape of virus (example is bacteriophages)
Define Capsid
protein coat of viruses
the capsid is composed of _____
protein subunits
How does the capsid maximize genetic storage?
comprised of a few different proteins, less proteins means less genetic code is needed
Spike glycoproteins job is to
bind ot the receptor on host cells
nucleocapsid protein
inner protein that contains nucleic acids
Steps of viral reproduction
- Adsorption
- Penetration and uncoating
- Replication of viral nucleic acids
- Synthesis and assembly of capsids
- Release of mature viruses
Virus adsorption entails
protein on viral surface binds to the receptor on host cells via random collisions
Penetration and uncoating entails
virus injecting nucleic material into the cytosol (sometimes nucleus) of the host cell
When does the nucleic material enter into the nucleus vs the cytosol of the host cell?
virus RNA is activated in the cytosol while virus DNA is active in the nucleus of the host cell
Viruses hijack host cell _____
machinery
When the virus has control of the host cell machinery the cell cannot ______
undergo transcription/ translation because the enzymes and ribosomes are being used by the virus
Viral polymerase creates
more copies of +/- RNA
Viral transcriptase is used to
transform +/- RNA into + RNA
Difference between + and - viral RNA
+RNA can be translated into proteins whiel -RNA cannot be
Viral replicase can
Create new copies of viral RNA from the same type of RNA
Viral integrase puts
Viral DNA into host DNA (H DNA can be used to create viral RNA)
Retrovirus replicate by
integrating +RNA into Host DNA to create viral proteins
Viral reverse trasncriptase is used to
transform viral +RNA into DNA
Synthesis and assembly of capsids entails
new viral particles being created (self assembly)
How are mature viruses released
enveloped viruses are released via exocytosis
