Viruses Flashcards
Who and how were discovered viruses?
Dmitri Ivanovsky: took diseased plant and blended it in blender. Poured through membrane filter and grew on agar. He tested each organism onto a plant. He then took filtrate and applied it to plant. Discovered unfiltered infectious poison.
What are the size ranges of most virueses?
20-1000 nanometers
What are the shapes of a virus?
polyhedral (diamond shape), helical (tube shaped), and complex viruses (spider like)
What is an enveloped virus?
A virus with a phospholipid bilayer covering with “spikes.”
What is an non-enveloped virus?
A virus without an covering. (naked)
What are capsids?
container made of protein.
What is a capsomere?
individual protein.
What types of genomes go viral?
more varied. It either has DNA or RNA not both. Viruses can be single/double stranded DNA or RNA. Can contain single or segmented DNA/RNA and can be linear or circular.
What are bacteriophage?
virus that attacks bacteria.
What are the steps in the lytic replication cycle?
attachment, penetration, biosynthesis, maturation, and release.
What is a plaque?
an area of virus that killed bacteria on agar. (similar to a colony)
What is a prophage?
virus inserted into hosts cells chromosome
What is an induction?
viral DNA is sent out of chromosome
What is lysogenic conversion?
prophage (addition to host cells genotype) changes the hosts cells phenotype.
What is a host range?
certain viruses infect certain cells.
What occurs in direct penetration?
capsid attaches to host cell (with matching receptors) and viral genome is released into cell.
What occurs during membrane fusion?
viral envelope melts into hosts cell membrane, uncoating releases the capsid (viral genome).
What is uncoating?
releases the viral genome
what is the effect of uncoating?
infects the cell
What is lysing?
bust through cell by lysing the host cell.
What is budding?
Capsid pushes through host cell thus breaking off. It is covered by the host cells membrane.
What are viral spikes?
proteins
What is hemagglutinin used for?
used for attachment. (entering)
What is Neuraminidase used for?
needed for budding. (exiting)
