Viruses Flashcards
How were viruses discovered?
After discovering bacteria, it was assumed that they caused all diseases.
However there was some diseases that could occur from solutions even after the bacterial cells had been removed
Diseases were caused by smthn much smaller than bacteria
What are viruses?
non-cellular parasitic microorganisms, which have no intrinsic metabolic capabilities
What are all viruses?
obligate intracellular parasites
First step of general overview of viral replication cycle?
Viral particle comes into contact and enters the host cell
What follows a virus entering a host cell?
It inserts its genome into the host cell
What happens after a viral genome is inserted?
Viral particles are made from it
What happens after viral particles are amde?
New virions are mae, and these are then released?
Mechanisms of viral release from host cell?
Budding release or lysis of the host cell
General structure of viruses?
Protein coat enclosing the viral genome
Sometimes there is an outer lipid envelope
WHat type of nucleic acid do bacterial viruses contain?
DNA
WHat type of nucleic acid do plant and animal viruses contain?
RNA
WHat if the function of the protein coat of a virus?
Protect the viral genome and facilitate entry into the cell
How may a virion acquire a lipid envelope?
Following a budding release it acquires some of the host cells lipid bilayer
What is the space between the capsid and the outer lipid envelope?
The tegument
What is in the tegument?
Contain viral enzymes, proteins and other things needed in early viral replication that it won’t be able to get from the host cell
What are glycoproteins on the surface of a virus used for?
Initial attachment to the host cell, and entry to the host cell
What is a capsid?
Protein shell or coat that encloses the viral genome
What is a capsomere?
Subunit of the capsid, capsid is made from many capsomeres
General shape of most viruses?
Spherical, cylindrical or icosaedral
Why are most viruses symmetrical?
To do with genome delivery to the host cell, and generating the structure from a limited genome size
What is the nucleocapsid/core?
The nucleic acid-protein complex representing the packaged form of the viral genome
What is the envelope?
A lipid membrane that surrounds some viruses
Can also contain glycoproteins
Importance of the viral capsid being symmetrical, and containing many capsomeres?
Economy of genetic info
Ease of capsid assembly
Ease of intracellular release of viral genome
How does the capsid being subunits mean it is genetically economical?
can generate capsid from little genetic info
