Exam 3 chapter 36 Flashcards
What does it mean that a virus is an obligate, intracellular parasite
It has to be inside another cell in order to anything and is parasitic
Are viruses themselves cellular
No…which means they are nonliving
What is lateral gene transfer
Transferring genes between organisms
Was the placenta partly derived from viruses
yes
In order to become stably incorporated into the human genome and inherited across generations, a viral gene must infect what type of cell
gamete
What is the difference between an epidemic and pandemic
An epidemic is a disease that rapidly infects a large number of individuals over a widening area (more local region) A pandemic is a worldwide epidemic (global) (ex: Spanish flu)
How many people has aids killed so far
30-35 million
virus particles are bigger than eukaryotic cells
false
What is the difference between a nonenveloped virus and an enveloped viru
Nonenveloped (“naked”) viruses: genetic material covered by a protein shell called a capsid
Enveloped: covered by a capside AND one more membrane-like envelopes
What are the functions of the capsid
Protects the genome while outside the host
Releases the genome when infecting a new cell
What is the central dogma of biology? Do viruses follow this
DNA mRNA proteins
Start with DNA which is transcribed into mRNA which is translated into proteins
Many viruses violate this
What are the three different classes of single-stranded RNA
Positive-sense viruses
Negative-sense viruses
Ambisense viruses
How does a virus replicate
There are two ways:
- via replicative growth (LYTIC): produces the next generation of virions and often kills the host cell
- in a dormant matter (LYSOGENIC): suspends virion production and allows virus to coexist with the host for a period of time.
Why do people die from HIV
Because they have too few T cells to fight infection
Virions are assembled during
lytic cycle only
