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27 Cards in this Set
- Front
- Back
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What is a virus?
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Nonliving and acellular. Injects its DNA/RNA into living cells.
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What are the structural parts of a virus?
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Outer capsid composed of protein, Inner core, and 1 short strand of DNA or RNA within the inner core.
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About how long is the strand of DNA/RNA within a virus?
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About 100 genes long.
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What is a virus considered? Hint: OIP
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Obligate Intercellular Parasite--must dwell within a cell and causes it harm
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What is a bacteriophage?
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A virus which only infects bacteria
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How does a virus attach to a bacteria cell?
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Uses prongs called receptors to attach to bacteria--lock and key situation. Certain viruses fit certain bacteria
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About how large is one virus?
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About 200 nanometers--thousands of viruses can fit inside a bacterium.
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Once the DNA/RNA is injected into the bacteria what occurs?
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The bacteria begin to copy virus DNA--become virus making factories until no more viruses will fit within the cell and it lyses, freeing the viruses to infect other bacteria
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What is the lytic cycle?
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bacteria generate viruses and then explode releasing viruses produced.
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What is the lysogenic cycle?
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Virus DNA inserts itself into bacteria's own DNA ring. It then hides there and bacteria replicate virus DNA when it goes through binary fission. Millions of bacteria are created which are infected.
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Can a virus in the lysogenic cycle go into the lytic cycle.
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Yes, at anytime. In fact this is how AIDS occurs from the HIV virus. Can stay hidden for 6 years and then become active.
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Is there a lytic phase in infected eukaryotic cells?
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No, instead eukaryotic cells form buds filled with the virus.
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What is a bud?
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Outpouching of the cytoplasm which fills with viruses until it breaks off and viruses are released. Cell remains intact.
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What happens when a eukaryotic cell is infected?
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The cell is hijacked and must now expend all its energy into producing more viruses. Loses its ability to do its job. This is why organisms become sick when infected.
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What is a retrovirus?
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Virus carries a strand of RNA instead of DNA.
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What must happen for a retrovirus to make a eukaryotic cell replicate it?
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The RNA must be transcribed and translated into DNA--RNA codes for this and makes the cell do the work.
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How is a virus RNA written? How is converted DNA written?
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RNAv and cDNA
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What is the enzyme which the retrovirus codes for to enable RNA to be converted to DNA?
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reverse transcriptase
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What happens once the RNA has been converted to cDNA?
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The cell begins replicated the virus
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Does a person die from the HIV virus or the AIDS virus?
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Neither. A person dies from infections/diseases due to the secondary affects of the HIV virus. It cause AIDS which destroys the immune system allowing other diseases/bacteria in to do harm.
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Do mutations occur in viruses?
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Yes, viruses also undergo mutations. Some make the virus no longer work, some make it better able to work.
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Why can some viruses be vaccinated against and some cannot?
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When viruses mutate very quickly it is impossible to create vaccines for them. Vaccines destroy the outer capsid. In some viruses the outer capsid is always mutation make vaccination impossible.
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What is an adenovirus?
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infects the cell, changes the mitotic processes of the cell-->cause of cancer!!
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How do antibiotics work and why don't they kill viruses?
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Antibiotics prevent bacteria from creating peptidoglycan which they use for binary fission. Effectively ends bacteria reproduction. Viruses do not use peptidoglycan so antibiotics have no effect.
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What is a prion?
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Nonliving protein which can exist outside the cell for up to 12 years
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What happens when a prion comes in contact with other proteins?
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Prions change the tertiary structure a protein rendering it inactive. Deactivation of proteins causes an organism to die or have very serious detrimental effects.
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What are some examples of diseases associated with prions?
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Chronic wasting disease in deer and mad cow disease in cows.
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