Exam 2

Question 1

What are the general characteristics of viruses?

Answer 1

• 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

Question 2

True or false: viruses are acellular (meaning not cells)

Answer 2

True

Question 3

True or false: Viruses have metabolism and can grow

Answer 3

False

Question 4

True or false: they depend on host cells to make copies of themselves

Answer 4

True: they are the ultimate parasite: cannot replicate unless they are in host cell using that cell’s machinery

Question 5

True or false: they come from specific origins

Answer 5

False: their origin is uncertain

Question 6

True or false: they seem to have collected pieces of nucleic acid from various sources

Answer 6

True

Question 7

True or false: they only infect specific lifeforms

Answer 7

False: they can infect nearly all lifeforms

Question 8

True or false: they are not only species specific but tissue specific (as far as what they will infect)

Answer 8

True

Question 9

How do corona viruses spread?

Question 10

How do they figure out you have a coronavirus?

Answer 10

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

Question 11

True or false: antibiotics designed to kill bacteria will eliminate viruses

Answer 11

False:
However, there are some antiviral drugs that are for controlling, but not curing, viral diseases

Question 12

Covid treatments?

Answer 12

Paxlovid - reduce symptoms and reduce time you are sick
Lagevrio
Veklury

Question 13

How is HIV treated?

Answer 13

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

Question 14

What is tamiflu?

Answer 14

it inhibits the neuraminidase and keeps the virus from exiting the cell
(lessen symptom severity and time of suffering)

Question 15

What do vaccines do? How are they built?

Answer 15

trigger our immune system without actually giving us the disease

• uses “live” virus but weakened
• using “killed” virus
• using molecular subunits of the virus

Question 16

How are developing vaccines time consuming?

Answer 16

It requires 6 stages
- discovery
- testing in cell cultures or animal models
- clinical testing in humans
- figuring out effectiveness and dosage

Question 17

How do vaccines work?

Answer 17

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

Question 18

How can we mitigate spread of a virus?

Answer 18

• limit contact via physical distancing and contact tracing
• wearing masks in public

Question 19

True or false: smallpox was eradicated from the human population by global vaccination

Question 20

What is horizontal transmission of plant viruses?

Question 21

What is vertical transmission of plant viruses?

Question 22

What are some common symptoms of plant viral diseases?

Answer 22

• hyperplasia (physically looks like tumors)

Question 23

What are prions?

Answer 23

Infectious proteins (not viruses and bacteria)

• incorrectly folded and convinces the other proteins in the body to fold the same way

Question 25

How did the discovery of viruses occur? Describe what happened and who did it.

Answer 25

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

Question 26

What new technology made in 1930s helped people see viruses?

Answer 26

Electron Microscopy

Question 27

True or false: almost all viruses are too small to be seen with a light microscope

Answer 27

True

Question 28

True or false: viruses have cells

Answer 28

False: they are acellular

Question 29

True or false: viruses have no metabolism and cannot grow

Answer 29

True!

Question 30

True or false: they can naturally make copies of themselves

Answer 30

False: they need host cells to do so

Question 31

True or false: their origin is very certain

Answer 31

False: uncertain origins

Question 32

True or false: they seem to have collected pieces of nucleic acids from various sources

Answer 32

True!

Question 33

True or false: they can only infect specific lifeforms

Answer 33

False: they can infect nearly all lifeforms

Question 34

Describe the prokaryote structures?

Answer 34

Some of them have in-folded membrane

Question 35

How do prokaryotes divide by which process which results in what kind of offspring?

Answer 35

binary fission; exact same offspring

Question 36

How many chromosomes do prokaryotes have?

Answer 36

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

Question 37

What are plasmids?

Answer 37

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

Question 38

How does binary fission work?

Answer 38

yields two identical daughter cells (except for plasmids)

Question 39

True or false; point mutations are very rare in prokaryotes

Answer 39

True: but high rate of cell division can cause many mutations

Question 40

True or false: one mutation in prokaryotes can change the phenotype

Answer 40

True: they only have one chromosome so one mutation will make a vast difference

Question 41

True or false: in prokaryotes, all mutations are passed in clones

Answer 41

True!

Question 42

True or false: in prokaryotes, selection favors the best clones

Answer 42

True, natural selection taking place. Theyve got short generation times so evolution is taking place rapidly

Question 43

What is recombination by transformation?

Answer 43

Griffith's experiment in 1928. Essentially horizontal gene transfer

Question 44

What is recombination by transduction?

Answer 44

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)

Question 45

What is recombination by conjugation?

Answer 45

- F plasmid conjugation - Hfr cell conjugation (High frequency recombination)

Question 46

What do we depend on as our primary producers?

Answer 46

Autotrophs