Viruses Flashcards
what are the general properties of viruses
they are of a small size, and their genome can be composed of either RNA or DNA. they are metabolically inert and do not possess ribosomes. some have enzymes. not able to carry out protein synthesis on their own.
why are viruses important clinically
in relation to disease obviously but also when considering taking samples as we have to use different types of swabs and cells to grow the viruses rather than agar because they can’t grow on their own
which microbes can be grown on agar plates
bacteria and fungi
are all viruses the same size
no there are variations
what is a virion
a complete virus particles
what do virions compose of
substructures, such as lipid membranes and capsids
what are capsids
protein shell in the centre of viruses
how does herpes simplex virus appear on electron micrographs
fried egg
why are viral capsids important structures
they protect the nucleic acid genome which can be RNA or DNA
what are the stages to viral replication
- attachment
- penetration
- uncoating
- synthesis of viral components
- assembly
- release
what are the different effects that viruses can have on cells
cytopathic
transformation
latent infection
what is cytopathic infection
this is when the virus causes the cell to die
what is an example of a virus causing a cytopathic effect in its target cell
herpes simplex one and its effect on oral mucosa epithelial cells
what is transformation as an effect of viruses on cells
the cell has not been killed but has been changed to a cancerous cell
what is an example of cell transformation as a result of viral infection
papilloma virus and oral cancer
what is latent infection
this is where the virus or elements of the viral nucleic acid remain in the cell with no obvious effects on cell function
what are some viruses that cause latent infection
recurrent herpes labialis and herpes simplex
what are some diseases that viruses are responsible for
AIDS and the flu
how do viruses produce proteins
they take over the operation of cells to manufacture new viruses
what must the virus first do in order to produce proteins in the host cell
the virus must gain access and convince the machinery to make multiple copies of it
are viruses specific
yes
how is the specifity of viruses achieved
through the receptors on the membrane of the cell which the viruses use to target their specific cells for infection
why can viral DNA be described as simple
only contains the genetic information to manufacture new virus parts
what happens once the virus has entered the cell and released its DNA into the nucleus
transcribed to RNA and the protein machinery of the host will translate the instructions into new components of a virus. these parts are assembled in the host cell and emerge when ready. this usually kills the cell.
