Virology I + II Flashcards
what does a virus consist of?
an infective agent that consists of a nucleic acid molecule in a protein coat.
too small to be seen in light microscopy
able to multiply only within the living cells of a host
what hosts can viruses be found in?
humans animals plants bacteria some can move between organisms 'host range' is where it is found
how can viruses be classified?
as viruses of mammals and non mammals
what is vertical transmission?
from mother to child
what is horizontal transmission?
between organisms
steps of the transmission cycle
1) introduction of the virus into a particular host range
2) amplification of the virus/animals act as reservoirs (factory farming)
3) insertion into other vectors (ticks, mosquitoes)
4) spread of the virus from vectors to secondary hosts
5) if a dead end host is reached the virus transmission stops
what is venereal transmission?
sexually transmitted
what is the definition of tissue tropism?
the tissues that viruses are found in
what allow viruses to evade the immune system?
the process of evolution allows viruses to replicate in tissues that favor the transmission between hosts.
what are the two ways that viruses can cause disease?
directly
product of their host range
indirectly
by promoting or inhibiting cell function
what are the features of a bacteria?
contain nucleic acid covered in protein,
have a cell wall
and can replicate outside of the cell
living organisms
what are the features of prions ?
they are proteins do not contain nucleic acid replicate inside the cell non living cause protein misfolding
what are features of viruses?
nucleic acid covered by proteins no cell wall may or may not have a lipid coat viruses must replicate in the cell 'obligate cellular parasites'
what are the 4 different types of viral genomes?
single stranded RNA
double stranded RNA
single stranded DNA
double stranded DNA
how do viral genomes encode information?
+ve and -ve sense
5β to 3β
or 3β to 5β
