Module 1- Acellular infectious agents Flashcards
what are the smallest of the microbes
viruses
how do viruses replicate
they cant on there own they require a host
how do viruses have there genetic information
they encode it, it can be DNA or RNA depending on the virus
what cant we determine how related viruses are to cellular life
because they do not carry genes that are consistently shared among all cells and viruses
what are viroids
like viruses in that they require host cells to replicate. unlike viruses they simply replicate their genome (single stranded circular DNA) which can spread cell to cell. so they seem to be limited to plants
what are some acellular infectious agents
viruses, viroids, satellites and prions
what are satellites
that are like a defective virus.
how do satellites infect cells
they encode nucleic acids enclosed in a protein shell like a virus and can infect new cells on their own
how do satellites replicate
they cant replicate them selves unless the cell they are within is also co-infected with a specific virus that provides essential enzymatic help to allow them to complete there life cycle
what are prions
proteins encoded by the host cell itself
how do infectious variants of prions work
infectious variants of this protein “misfold” to create a new form that has a tendency to bind to other copies of normal proteins and catalyze those to also misfold. these misfolded copies can make cause additional normal copies to misfold etc…
what are prions considered infectious
because these misfolded proteins can misfold others and therefor be infectious
what proteins can prions be problematic for
for proteins that are significantly simular in a species used for food by humans and sufficiently stable that they can remain infective following normal food processing and start the process within a human host. ie mad cow
