Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MicroEco > Lecture 11 - Virus Ecology II > Flashcards

Lecture 11 - Virus Ecology II Flashcards

1
Q

What is the “kill the winner” model?

A

as the number of hosts increases so will the virus = causes host number to decrease = virus number decreases = causes host number to increase = cycle starts again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In the “kill the winner” model, what is the host (prokaryote in this case) doing at each cycle?

A

constantly evolving mechanisms to help resist viral infections by becoming stronger, change surface proteins, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If the hosts (prokaryotes in this case) are constantly evolving, why are they still getting infected by viruses?

A

the virus evolves with its host cell as it regenerates faster than the host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is another name for the “kill the winner” model? Why is this name fitting?

A

“Red Queen” hypothesis because something is always trying to chase something else but it never catches up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the r/K selection theory?

A

describes the trade-offs that organisms do between quantity and quality of offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the characteristics of r-strategists?

A

small opportunistic organisms, reproduce quickly, lots of progeny, short life-span

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are characteristics of K-strategists?

A

larger organisms with longer lifespan and less progeny; invests more on their offspring = become better competitors and live longer due to this investment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which are viruses mostly classified as: r or K strategists? Why?

A

r-strategists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Are there any viruses that are considered to be K-strategists?

A

lysogenic viruses that are not considered virulent (they don’t lyse cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are 2 ways you can classify viruses on the r/K selection theory?

A

based on how their host is classified OR the viral infection they cause

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In the r/K selection theory, how can viruses be classified based on the type of viral infection they cause?

A

acute infections = r-strategists | chronic infection = K-strategists (HepC, HIV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are rank abundance curves?

A

chart that illustrates relative species abundance to other species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What can the rank abundance curve give insight to?

A

strategies used by organisms to survive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

On the rank abundance curve, what will rank as the most abundant species? (number rank)

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

On a rank abundance curve for marine prokaryotes, what type of prokaryote would you assume would be most abundant and least abundant? Based on how fast/slow they grow and their resistance to viruses.

A

Most abundant = slow growers and more resistant | Least abundant = fast growers and more susceptible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

On a rank abundance curve for marine viruses, which would be most abundant and least abundant and why? Lytic vs. Lysogenic viruses.

A

Most abundant = lytic viruses because of higher burst output, more infection of prey | Least abundant = lysogenic viruses because they grow slower and integrate, lower burst size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do viruses do in the ocean?

A

will influence the composition of marine communities, can cause disease, and help drive biochemical cycles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the percentage of bacteria in the ocean that are lysed every day? (estimate)

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the 4 roles of marine phages?

A

global biogeochemical cycles, regulate microbial diversity, cycle carbon in marine food webs, prevent bacterial population explosions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the viral shunt?

A

the production of DOM/POM and its later use by microbes | a way to cycle nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does the viral shunt work?

A

viruses infect and lyse marine heterotrophs and autotrophs &raquo_space; lysed cells release nutrients &raquo_space; DOM/POM available for uptake by other marine heterotrophs and autotrophs

22
Q

What are the environmental factors that can inactivate viruses?

A

UV light, temperature, salt, pH, competition, pollution, grazers, inorganic/organic particles that viruses can absorb to and cause to aggregate

23
Q

What would be a consequence to reducing the infectivity of the viruses?

A

will alter the microbial population

24
Q

What are the environmental factors that will alter host dynamics?

A

pollution, UV, temperature, viral pool, number of hosts, infection susceptibility and morphology, and viral life strategy

25
Q

What environmental factors influence the infectious activity of viruses? (from most to least effective)

A

UV, inorganic, organic particles

26
Q

What environmental factors influence the viral contact rate to a host? (from most to least effective)

A

Abundance, host size, host morphology

27
Q

What environmental factors influence viral adsorption to the host? (from most to least effective)

A

Temperature, salinity, host physiology

28
Q

What environmental factors influence the life strategy viruses will undertake (lysogenic or lytic)? (from most to least effective)

A

Nutrient availability, UV, pollution

29
Q

Why are algal blooms an issue?

A

a huge increase in algal cells that use up all of the O2 in the water

30
Q

What do algal blooms cause and why?

A

dead zones which are zones of dead marine animals and microbes because the algae are taking up all of the O2

31
Q

What is phage therapy?

A

using phages to target bacteria that causes infections in humans

32
Q

How can viruses help with the algal bloom problem? What is a benefit of this other than solving the bloom problem?

A

infecting the algae = lyses cells and leads to the collapse of the blooms | results in greater species diversity (more life)

33
Q

What are pandoraviruses?

A

largest viruses discovered almost as big as cells but still dependent on host and infects amoebas

34
Q

What are the 2 new viruses discovered and how do they lack viral characteristics?

A

halophilic virus lacks structural protein | a virus encoding its own membrane

35
Q

What is SAR11?

A

an alpha-proteobacterial lineage; most abundant bacteria found in the ocean that reportedly has never been infected by a virus until now

36
Q

What may be a reason as to why SAR11 is now getting infected by viruses?

A

due to population changes

37
Q

Why are viruses that infect commercially important organisms significant?

A

viral diseases can cause enormous loss in production and revenue

38
Q

Name the 3 viruses discussed that infect fish farms?

A

Viral hemorrhagic septicemia virus (VHSV) | infectious salmon anemia virus | infectious hematopoietic necrosis virus

39
Q

How do the virus that infect farmed fish spread to infect wild marine fish?

A

hatcheries are great for virus to colonize and spread &raquo_space; somehow these viruses end up in the ocean and because they have a wide host range = can infect multiple fish and can spread to other parts of the world

40
Q

What is a generalized transducing agent?

A

virus-like particle that carries host DNA (not viral DNA) that can be transmitted via liposome

41
Q

How does a generalized transducing agent affect their marine hosts?

A

horizontal gene transfer

42
Q

What are the 2 ways marine eukaryotic viruses affect their hosts?

A

Red Queen and Cheshire Cat

43
Q

What are 3 ways marine phages affect their hosts?

A

lysis = bacterial mortality | horizontal gene transfer = niche expansion/new metabolisms | accessory gene expression in cyanobacteria

44
Q

What is significant/unique about how cyanobacteria gained accessory genes via the marine phage?

A

cyanobacteria obtained genes for photosystem II which may have been brought by phage that accidentally packaged those genes from an infected host

45
Q

What is the Cheshire Cat effect?

A

a species can take a form that is undetectable/resistant to viruses and then retakes its normal form soon after

46
Q

What species does the Cheshire Cat focus on?

A

algal species that a virus affects

47
Q

What drove to the discovery of the Cheshire Cat effect?

A

viral ecologists didn’t understand why an algal species didn’t invest and evolve in viral defense mechanism

48
Q

How does an algal species perform the Cheshire Cat effect?

A

the species can be in a diploid-form that causes algal blooms and is susceptible to viral infections; it can also become a haploid form which is mobile and resistant to viruses

49
Q

How is the algal species way of evolving viral defense mechanisms considered to be a Cheshire Cat effect?

A

the haploid form is really hard to see under microscope

50
Q

What do the lysogenic species provide when the abundance of hosts are low

A

a mean of persistence for viruses

MicroEco (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions