Viruses Flashcards
viruses
a sub-microscopic infectious agent that can only reproduce in a host cell
DNA
deoxyribonucleic acid, form a double helix carrying genetic instructions for the development
RNA
Ribonucleic acid, a nucleic acid present in all living cells that has structural similarities to DNA.
bacteriophage
viruses that infect bacteria
capsid
protective protein layer
replication
viral genome takes over host cell, destroys host DNA and uses host’s machinery to make copies of its own genome and protein coat
lytic cycle
- attachment: virus attaches to host
- entry: inserts DNA into host cell; protein coat might enter or stay outside
- replication: viral genome takes over host cell, destroys its DNA and uses the host’s machinery to replicate its own DNA and protein coat
- Assembly: virus parts are assembled
- lysis/release: new virus particles leave host and host cell dies
lysogenic cycle
- insert genome into host cells DNA
- Host cell replicates and viral genome gets replicated with it
- lytic cycle is triggered
- does the lytic cycle
lysis
leaves the host cell
retrovirus
contain an enzyme reverse transcriptase (lets them change genome from RNA to DNA)
carries out lysogenic cycle
more dangerous than other types of viruses
can mutate and lay dormant
what is a virus
a sub-microscopic infectious agent that can only reproduce in a host cell
why are viruses not ‘alive’
no organelles, no metabolization, can’t reproduce on their own
how do we classify viruses
based on 3 things
1. type of nucleic acid (DNA or RNA)
2. single stranded or double stranded
3. whether they can use reverse transcriptase or not
what can we learn about viruses from their disease patterns
how virulent the viruses is from their disease patterns
how are viruses used in biotech
used to genetically modify organisms
