Biology (viruses) Flashcards
characteristics of virus (non living)
no cell membrane no organelles not cells do not respire do not produce waste need a host to live and reproduce
characteristics of a virus (living)
contain DNA
reproduce
life cycle
lytic cycle
speed= fast effect on host cell= lysis (explodes) no chance of reactivating virulent examples: cold, influenza, chicken pox
lysogenic cycle
speed = slow effect on host= prophase chance of reactivation temperate HIV
viral diseases that can be treated with vaccines
measles
flu
chicken pox
viral diseases that can’t be treated with vaccines
HIV
herpes
common cold
viral infections are preventable by?
vaccines
what are vaccines?
inject you with dead or weak virus
you produce antibodies
the antibodies stay in bloodstream
if re-exposed identify and make more antibodies
the immune system’s defence for viruses is an?
antibody
key components of a virus (bacteriophage)
capsid
protein coat
nucleic acid (DNA, RNA)
what are retroviruses
RNA converted into DNA
the DNA can remain dormant (lysogenic)
work backwards RNA-DNA
e.g HIV
what are viroids
causes disease in plants
single strand of RNA
they don’t have a protein coat
what are prions
cause diseases in plants
no DNA or RNA only protein
common viral diseases
measles common cold polio small pox mumps rabies HIV
lytic
the cycle of viral replication which causes the host cell to burst open
