Exam 4 - Lecture 19

Question 1

true or false: “this whole lecture is an SOS”

Answer 1

… :D

Question 2

a single _______ causes a particular disease.

Answer 2

microbe

Question 3

true or false: a disease can be caused by many different microbes.

Answer 3

true; examples are conjunctivitis and meningitis

Question 4

what is symbiosis?

Answer 4

an association of two or more different species of organisms (good or bad).

Question 5

in symbiosis, at least one member or the pair benefits from the relationship. the other may be:

Answer 5

• injured
• relatively unharmed
• may also benefit

Question 6

in symbiosis, the microbe is the _________ and the larger organism is the ______.

Answer 6

• symbiont
• host

Question 7

what is an ectosymbiont?

Answer 7

an organism located on the surface of another organism (like bacteria on skin)

Question 8

what is an endosymbiont?

Answer 8

organism located within another organism (like bacteria in our gut)

Question 9

what is a consortium?

Answer 9

a host with more than one associated symbiont (like us)

Question 10

what are the seven types of microbial interactions?

Answer 10

• mutualism
• cooperation
• commensalism
• predation
• parasitism
• ammensalism
• competition

Question 11

symbiotic relationships can be what three things? (time wise)

Answer 11

• intermittent
• cyclic
• permanent

Question 12

what is mutualism?

Answer 12

• both partners benefit
• some degree of obligation involved
• partners cannot live separately; codependency

Question 13

what kind of interaction do aphids and Buchnera aphidicola have? who is the symbiont?

Answer 13

• (endo)symbiont: B. aphidicola
• mutualistic interaction
• aphids consume sap deficient in essential amino acids and vitamins
• insect provides vitamins and amino acids (Arg) and gets secure habitat and nutrients in return

Question 14

the inability of the aphid/B. aphidicola to grow without the other is an example of:

Answer 14

coevolution

Question 15

what is the relationship between termites and a protozoan? who is the symbiont?

Answer 15

• mutualistic interaction
• symbiont: the protozoan with no name
• termites eat wood that contain cellulose and are unable to break up the long chains of glucose
• protozoans digests the cellulose and provides nutrients for the protozoan in return for food from the termite

Question 16

what mutualistic relationships does the protozoan from the termite-protozoan relationship have?

Answer 16

• N2 fixing bacteria to make NH3
• bacteria TG1 makes glutamine (Gln) from NH3
• spirochetes provide motility for protozoan

Question 17

what are ruminants?

Answer 17

animals that have stomachs divided into four compartments and are able to acquire nutrients from plants by fermenting them in a specialized compartment (rumen) prior to digestion

Question 18

what is the rumen?

Answer 18

• upper part of the ruminant stomach
• contains large, diverse population of microbes

Question 19

rumen ecosystem order of events:

Answer 19

• plant material (grass) is coated w saliva and swallowed
• in the rumen, grass is coated with microbes and broken down into pulpy, partially digested mass
• regurgitated, chewed, re-swallowed
• liquified grass passes into omasum/abomasum
• further digested

Question 20

the microbial community within the ruminant have their own ____________ relationships.

Answer 20

• mutualistic

Question 21

what is cooperation?

Answer 21

a relationship that benefits both organisms but is not obligatory for the survival of either organism

Question 22

cooperation typically involves ___________ relationships.

Answer 22

syntrophic

Question 23

what are syntrophic relationships?

Answer 23

when one species lives off the byproducts of another species
- often involves carbon and nitrogen/sulfur cycles

Question 24

what is commensalism?

Answer 24

one organism benefits while the other is unaffected

Question 25

the organism that benefits from commensalism is called the:

Answer 25

commensal

Question 26

true or false: commensalism relationships are often syntrophic.

Answer 26

true

Question 27

true or false: commensals can live once separated from the host.

Answer 27

true

Question 28

what is an example of commensalism in nitrification?

Answer 28

- two different bacteria carry out nitrification together - NH3 to NO2 by Nitrosomonas - NO2 to NO3 by Nitrobacter

Question 29

the microbial succession during the spoilage of milk and biofilm formation are examples of what type of relationship?

Answer 29

- commensalism that occurs when the environment is made more favorable by one species for another

Question 30

what is predation?

Answer 30

- one organism gains (predator) and the other is harmed (prey) - this "harm" is usually killing

Question 31

true or false: predators can only attack from outside the cell.

Answer 31

false; they can attack from the outside or inside of the prey cell

Question 32

what are four examples of bacteria that use predation?

Answer 32

- Bdellovibrio: penetrates cell wall, grows outside plasma membrane in periplasm - Vampirococcus: epibiotic mode of attacking prey (lives on the surface) - Daptobacter: pepntrates prey then directly consumes the cytoplasmic contents totally intracellularly - Myxococcus (wolf pack): uses gliding motion to creep, overtake prey, and release degradative enzymes

Question 33

what is parasitism?

Answer 33

- one organism gains and the other is harmed - the host is typically not killed (at least until the parasite can reproduce)

Question 34

there is always some degree of ______________ between a host and a successful parasite.

Answer 34

co-existence

Question 35

what is the hallmark(s) of parasitic relationships?

Answer 35

- not beneficial for the host - host grows better without the parasite

Question 36

what is ammensalism?

Answer 36

an association between two organisms where one is harmed/inhibited and the other in unaffected

Question 37

what specific type of ammensalism is based on the release of a specific compound?

Answer 37

antibiosis

Question 38

what is an example of an ammensalism relationship?

Answer 38

antibiotic production by fungi and bacteria

Question 39

what bacteria do South American Attine acts use to control fungal parasites? what kind of relationship is this for the bacteria and the fungi?

Answer 39

- antibiotic-producing Actinobacteria - ammensalism

Question 40

what is competition?

Answer 40

occurs when two organisms try to acquire the same resource

Question 41

what are the two possible outcomes of competition?

Answer 41

- one organism dominates - sharing of the resource (both survive at lower pop levels)

Question 42

what is a microbiome/microbiota?

Answer 42

all of the microbes living in and on the human body

Question 43

the ratio of bacteria to human cells has been changed from _____ to _____.

Answer 43

from 10:1 to 1:1

Question 44

how many microbial genes are there? how about human genes?

Answer 44

- over 1,000,000 microbial - 23,000 human

Question 45

all of the genes of the host and the microbiota are called the:

Answer 45

metagenome

Question 46

what are superorganisms?

Answer 46

- gene-encoded metabolic processes of the host become integrated with those of the symbiont - a blend of host and microbial traits where host and microbial cells co-metabolize various substances, resulting in unique products

Question 47

normal microbiota varies depending on:

Answer 47

- age - sex - diet - anatomical site

Question 48

when does the relationship between microbiota and the host occur?

Answer 48

at birth

Question 49

true or false: antibiotic treatment can disrupt the microbiome balance.

Answer 49

true, but it can return to "normal" after the antibiotics are removed

Question 50

is the normal microbiota interaction with the human commensalism, mutualism ,or cooperation?

Answer 50

mutualism

Question 51

normal microbiota often prevent _____________ by pathogens.

Answer 51

colonization

Question 52

what is pathogenicity?

Answer 52

ability to produce pathological change of disease