Lecture 37 - Virology Intro Flashcards
Do all viruses cause disease? If not, why not?
No - can be avirulent, not in primary host, latent infection, or host mechanisms stop disease symptoms
Define virome
all viruses in given environment (viral biome)
T/F: viruses outnumber bacterua 10:1 in most ecosystems
TRUE
What are the 3 theories of viral origin?
- self-replicating molecules that existed before cells
- evolved from genetic elements within cells that gained the ability to move between cells
- ancient intracellular parasites that lost other functions
what are the reasons that there are new viruses?
- mutations
- zoonoses development
- genetic shift
- recombination events
how do zoonotic viruses like SARS coronavirus spread to humans
- emerge from bats
- go to intermediate species in a new environment
- infect humans in close contact
T/F: mosquitoes are a vector for many viruses
TRUE
what are the ways humans can be infected by zoonotic viruses
- bats to intermediate species
- mosquito-borne
- primates to humans
- food animal-borne
the spread of HIV or ebola virus to humans illustrates what kind of viral spread
between closely related animal species
what is viral genomics teaching us
viruses have always existed but we are recently finding them via technology
why are viruses considered infectious pathogens
- spread to other cells or hosts
- infection alters fundamental cell processes
what are the 4 steps of viral replication
- enter
- replicate
- exit
- spread
what two structures do viruses have that help replication
- nucleic acid genome
- protective coat
what do viruses lack?
- functional ribosomes
- mitochondria
- means to generate metabolic building blocks
how can viruses be categorized
obligatory intracellular parasites