Viruses Flashcards
How were viruses first discovered
Dimitri Ivanovsky discovered that tobacco mosaic virus could pass through a filter capable of trapping bacteria.
Why are viruses not considered living organisms
They can not replicate on their own and must find a host. As a result they are not found on the tree of life
What do viruses usually consist of
A nuclei acid surrounded by a protein coat
What is a Virion
An extracellular virus that has not yet infiltrated a cell
How large are most most viruses
20-300nm
What are different methods of classifying viruses
The kind of host they infect
The type of nucleic acid they posses
Whether they have an external envelope
What are the types of nucleic acid used in viruses
Double stranded DNA
Single stranded DNA
Single stranded mRNA
Double stranded mRNA
What does a viral envelope consist of
A lipid bilayer with proteins (usually glycoproteins) embedded in it
What is the process of viral infection
Virion attaches to susceptible host cell
The Virion injects either itself of its nucleic acid into the cell
The nucleic acid gets duplicated and viral capsids are formed by the host cell
The mature viruses will build up in the host cell until it undergoes lysis and they are released
What is the difference between the lytic and lysogenic pathways
Lytic pathway: virus infects cell and immediately begins replicating itself until the host cell undergoes lysis
Lysogenic pathway: the virus infects the cell and imbeds its genome into that of the host. When the host cell replicates itself the daughter cells will contain the viral genome. Once the genome is induced it will follow the lytic pathway
What are the methods of transmission and infection
Via aerosols or physical contact
Via vectors
