Unit 1 - Virology Flashcards
What is a host range
Spectrum of what the virus can affect. Only affect certain cells such as hair
What are the general characteristics of viruses
Can have multiple shapes,
have a capsule and some have an envelope,
no organelles,
have either DNA or RNA or,
need an electron microscope to view, need a host,
lysogenic or lytic cycle
What is a bacteriophage
A virus that only affects bacteria
What is the structure of a bacteriophage
Have s capsid, nucleic acid and sometimes an envelope
What are the five steps of the lytic cycle for a bacteriophage
Attachment, penetration, biosynthesis, maturation, release which lyse the cell
Describe the attachment phase of the lytic cycle
Specific and based on host range
Describe the penetration phase of the lytic cycle
Lysosome makes holes (enzyme)
Describe the biosynthesis phase of the lytic cycle
Replication. Uses host cell mechanisms for replication
Describe the release phase of the lytic cycle
Lyse the cell to allow virus to infect neighbour cells
What are the 5 stages of the lysogenic cycle
Attachment Penetration Dna integration Host cell replication Virus dna removes itself from the host cell dna
Describe the DNA integration phase of the lysogenic cycle
The virus puts its DNA into host DNA. The virus now becomes a prophage
Describe the host cell replication phase of the lysogenic cycle
It also replicates the viruses DNA
Describe the virus DNA removal phase of the lysogenic cycle
The virus DNA removes itself from the host cell DNA and can now join the lytic cycle and then go through biosynthesis
What’s the difference between animal and bacterial viruses
In animal viruses the full virus goes into the host cell but with bacterial viruses the DNA/rna goes inside
How does virus remove its envelope/capsid after penetration
By fusion/endocytosis
Where is Viral replication in bacterial infections
In the cytoplasm
In DNA animal viruses the replication occurs where
️Nucleus
In rna animal viruses the replication occurs where
In the cytoplasm
What does a lysogenic cycle mean for an animal
Chronic infections, latent infection, slow viral infection and cancer
What happens to a cell if a virus has an envelope
It won’t lyse the cell
What happens to a cell if a virus doesn’t have an envelope
It will lyse the cell and steal part of the plasma membrane
What are the 4 things a virus needs to cause disease
A route of infection
Disemmenation (to get where it needs to be - generalized or local)
Cause disease (has an incubation period)
Shed and transmit itself
Describe an acute disease
Short term, clinical signs, persistant
Describe a latent disease
Virus is inside of host cell but doesn’t have symptoms
Describe a chronic disease
Virus is present and can be shed
Describe a slow infection
Virus load increase over years and eventually kills you
What is vertical transmission
Mother to child
What is horizontal transmission
Via fomites/vectors from person to person
