SB5f Virus life cycles Flashcards
Why are viruses described as particles rather than cells?
.Viruses are acellular, they’re not cells.
.They all consist of genetic material surrounded by a protein coat (capsid)
.Viruses cannot copy themselves on their own
What must viruses do in order to reproduce?
viruses must use host cells and this destroys the host which leads to cell damage and death.
What do viruses use to make new virus copies?
host cell machinery e.g. ribosomes. They can then break out of the cells causing lysis.
What is the role of the capsid?
to protect the genome.
What is the role of the attachment protein?
to allow viruses to invade host cells.
What is lysis?
the disintegration of a cell by rupture of the cell wall or membrane.
What do viruses that cause cell lysis undergo?
Lytic or lysogenic pathway
lytic pathway? APRAR
Attachment ~ virus attaches to surface of host cell
Penetration ~ virus injects its genetic material into host cell
Replication ~ viral genetic material takes control of hosts cells machinery and starts making copies of itself
Assembly ~ newly formed viral components come together to form complete viruses
Release ~ host cell bursts open releasing newly formed viruses
lysogenic pathway? APIDA
Attachment ~ virus attaches to the surface of host cell
Penetration ~ virus injects its genetic material into host cell
Integration ~ viral genetic material becomes part of host cells DNA
Dormancy ~ viral DNA remains dormant and is replicated with the host cells DNA during cell division
Activation ~ under certain conditions the viral DNA can become active and enter the lytic cycle
