Viruses Flashcards
Test 4
T/F: viruses are living organisms
F
Lack nucleus, mitochondria, cell membrane, ribosomes
We want to ______ an active virus
inactivate
Viruses are either _____ or ______
Active or inactive
Why are viruses considered intracellular parasites?
They cannot multiply –> have to invade a specific host cell
after invasion, instructs host cell to make and release new viruses
Differentiate between the lysogenic cycle in the lytic cycle
Give examples
Lysogenic cycle: virus slowly pinches off the cell
-lasts years/decades
Ex) HIV
Lytic cycle: Burst host cell r/t acute infections
-clears out fast
Ex) Flu
T/F: Virus have no effects on animals & plants
F
Plants effected the worst actually
What are the 3 main parts of a virus?
- external coating (outer coat/Capsid): repeating proteins that bind & form a capsid
- core containing nucleic acids (DNA/RNA)
- spikes: target specific cell that it’s going to infect
Are DNA strands mostly single or double stranded? RNA?
DNA: double
RNA: Single
But DNA/RNA could be either
Single stranded DNA = Parvo
What does retrovirus mean? What are examples
Starts off as RNA but changes to DNA & then put into nucleus of host cell
-All these viruses can be reactivated
Ex) HIV, Herpes, HPV16/18
T/F: retroviruses can be reactivated
T
What is the enzyme used in retroviruses to convert RNA to DNA?
Reverse transcriptase
T/F: all viruses have an antiviral therapy
F
What is the difference between a naked & enveloped virus?
Naked: Has capsid, nucleic acid, & spike
Enveloped: In addition to things listed naked virus; has an enveloped “outer cell membrane”
What does the outer cell membrane come from in an enveloped virus? What type of cycle do you see this in?
part of the cell host that it has infected
lysogenic cycle
What is the viral spike in HIV? What does it target?
GP120
CP4(+) proteins on T cells & marcophages
