Viruses Flashcards
how could one see a virus
using an electron microscope
what specific type of nutrition do viruses have
they are obligate parasites
what does it mean that they are obligate parasites
they can only replicate inside a living cell
what type of cells do viruses infect
all types of cells
what is peculiar about viruses
they are non cellular
why can we say that viruses are non cellular
they don’t have a cell wall or cell membrane or any cell organelles
what do viruses consist of?
a strand of DNA or RNA enclosed in a protein coat
1 way of classifying viruses
based on their shape
3 shapes of viruses
rod, spherical , complete
what does the complex virus shape look like
like a spacecraft
2 living features of viruses
they have genetic material (DNA or RNA)
they can replicate (within a living cell)
4 non-living features of viruses // comment on the difficulty of classifying them as living things
they are non-cellular
they don’t have mitochondria, chloroplasts or ribosomes
they only have 1 type of nucleic acid (DNA or RNA)
they cannot replicate outside of a cell
can viruses live outside of a living cell
yes, they just can’t replicate
how long does the replication of viruses take?
about 30 minutes
can viruses be grown on agar plates and explain
no as agar is not made of living cells, won’t be able to reproduce
3 types of cells that viruses might have as a host
animal, plant and bacterium
5 stages of viral replication
virus attaches to host cell
DNA replicates
assembly of viral DNA and protein
host cell bursts and it is released
where does the virus attach to the host cell?
cell wall or membrane
what goes inside/stays outside the host cell?
when the virus enters, the protein coat stays outside
how does the virus replicate?
it uses the host’s organelles to produce copies of viral DNA and protein
how are new viruses made?
by assembling the viral DNA and protein
how many viruses can be released when the host cell bursts?
up to 100,000 new viruses
3 things that happen to the new viruses after they are released
may infect other cells, be attacked by antibodies or white blood cells, or be released into the environment
3 harmful effects of viruses
human disease
plant disease
anima disease
3 human diseases caused by viruses
cold sores (herpes)
common cold
flu
4 ways human disease can be contract from a virus
transfer of body fluids
by contacts
bt droplet infection
by a bite from a vector (carrier)
what does plant disease result in?
crop damage
1 plant disease caused by viruses
mosaic disease in tobacco plants
2 animal diseases caused by viruses
foot an mouth eg. cow
rabies eg. dogs
4 beneficial effects of viruses
genetic engineering (gene therapy) kill bacteria (bacteriophages) control pests (biological pest control) formation of vaccines
2 ways in which we can control vaccines
general and specific defence systems of the body control viral infection
vaccines are used to give protection against viruses
are viruses affected by antibiotics
no
