Exam 2 Flashcards
What are the general characteristics of viruses?
- not “living”
- pathogenic
- adaptable
- need host for reproduction
- no organelles
- MAY have membranes
- nucleic acid
- MAY have carbs or glycolipids
- can integrate in the host
True or false: viruses are acellular (meaning not cells)
True
True or false: Viruses have metabolism and can grow
False
True or false: they depend on host cells to make copies of themselves
True: they are the ultimate parasite: cannot replicate unless they are in host cell using that cell’s machinery
True or false: they come from specific origins
False: their origin is uncertain
True or false: they seem to have collected pieces of nucleic acid from various sources
True
True or false: they only infect specific lifeforms
False: they can infect nearly all lifeforms
True or false: they are not only species specific but tissue specific (as far as what they will infect)
True
How do corona viruses spread?
How do they figure out you have a coronavirus?
molecular test - detect genetic material (PCR- Curative)
Antigen test (most used and most cheap):
- to detect protein on the surface of the virus (Binax home test)
Antibody test
- looks for antibodies in the blood and it figures out if someone had been infected in the past or had been vaccinated
True or false: antibiotics designed to kill bacteria will eliminate viruses
False:
However, there are some antiviral drugs that are for controlling, but not curing, viral diseases
Covid treatments?
Paxlovid - reduce symptoms and reduce time you are sick
Lagevrio
Veklury
How is HIV treated?
treated with a “cocktail” of drugs
- fusion inhibitors:
- one drug blocks reverse transcriptase of the virus
- integrase inhibitors: block DNA that was made that prevents it from getting into the host cell genome
-protease inhibitors: keep the virus from getting into the cell
What is tamiflu?
it inhibits the neuraminidase and keeps the virus from exiting the cell
(lessen symptom severity and time of suffering)
What do vaccines do? How are they built?
trigger our immune system without actually giving us the disease
- uses “live” virus but weakened
- using “killed” virus
- using molecular subunits of the virus
How are developing vaccines time consuming?
It requires 6 stages
- discovery
- testing in cell cultures or animal models
- clinical testing in humans
- figuring out effectiveness and dosage
How do vaccines work?
It basically primes the immune system to react when the body is exposed to virus
- A few can work during early stages of viral infection (Ex: rabies)
It contains “live” (attenuated) virus
How can we mitigate spread of a virus?
- limit contact via physical distancing and contact tracing
- wearing masks in public
True or false: smallpox was eradicated from the human population by global vaccination
What is horizontal transmission of plant viruses?
What is vertical transmission of plant viruses?
What are some common symptoms of plant viral diseases?
- hyperplasia (physically looks like tumors)
What are prions?
Infectious proteins (not viruses and bacteria)
- incorrectly folded and convinces the other proteins in the body to fold the same way
How did the discovery of viruses occur? Describe what happened and who did it.
Dmitri Ivanosky- first guy to isolate one
He learned that filtered sap from an infected plant gave healthy plants the same tobacco mosaic virus and realized it wasn’t bacteria
What new technology made in 1930s helped people see viruses?
Electron Microscopy
True or false: almost all viruses are too small to be seen with a light microscope
True
True or false: viruses have cells
False: they are acellular
True or false: viruses have no metabolism and cannot grow
True!
True or false: they can naturally make copies of themselves
False: they need host cells to do so
True or false: their origin is very certain
False: uncertain origins
True or false: they seem to have collected pieces of nucleic acids from various sources
True!
True or false: they can only infect specific lifeforms
False: they can infect nearly all lifeforms
Describe the prokaryote structures?
Some of them have in-folded membrane
How do prokaryotes divide by which process which results in what kind of offspring?
binary fission; exact same offspring
How many chromosomes do prokaryotes have?
one chromosone: circular DNA molecule w/ binding proteins (no histones for most, but some Archaeans have histones)
- carries genes for all vital functions
- much less DNA than eukaryotes
Little space in between genes
What are plasmids?
Prokaryotic tiny rings of DNA that replicate independently outside of the cell cycle. Plasmids are not essential for life but add diversity
- can carry drug resistance genes, ferment some kinds of sugars, carry toxins
How does binary fission work?
yields two identical daughter cells (except for plasmids)
True or false; point mutations are very rare in prokaryotes
True: but high rate of cell division can cause many mutations
True or false: one mutation in prokaryotes can change the phenotype
True: they only have one chromosome so one mutation will make a vast difference
True or false: in prokaryotes, all mutations are passed in clones
True!
True or false: in prokaryotes, selection favors the best clones
True, natural selection taking place. Theyve got short generation times so evolution is taking place rapidly
What is recombination by transformation?
Griffith’s experiment in 1928. Essentially horizontal gene transfer
What is recombination by transduction?
DNA is carried across by bacteriophage virus
- the phage will inject its viral DNA into the bacteria and uses the cell resources to make more phages - lytic cycle
IN TRANSDUCTION: the bacteriophage traps the bacterial DNA instead of viral DNA. It essentially makes an oopsy.
- the phage carries DNA from the donor to a recipient cell
- the new alleles insert into recipeint cell chromsome (recombination - increased diversity of population)
What is recombination by conjugation?
- F plasmid conjugation
- Hfr cell conjugation (High frequency recombination)
What do we depend on as our primary producers?
Autotrophs
