Microbio 1.3

Question 1

“Normal” growth conditions that favor growth of non-extremophiles are:

Answer 1

o Atmospheric pressure
o Temperature of 20-40oC
o Near-neutral pH
o Salt concentration of ~0.9%
o Ample nutrients

Question 2

Psychrophile

Answer 2

prefers cold environments (4 degrees C)
tundra, fridge

Question 3

mesophile

Answer 3

prefers warm temperatures (39 degrees C)
soil, water, bodies

Question 4

thermophiles

Answer 4

thrive in hot temps (60 degrees C)
surface of the soil

Question 5

Hyperthermophiles

Answer 5

thrive in extreme heat, their enzymes function best at 88 degrees
hot springs

Question 6

Nonhalotolerant

Answer 6

cannot tolerate salt at all
found commonly in freshwater

Question 7

Halotolerant

Answer 7

can tolerate salt but does not prefer to be around it
hypersaline lakes, freshwater

Question 8

Halophile

Answer 8

prefers being in salty environments
ocean, salt mines

Question 9

Acidophiles

Answer 9

Prefer acidic environments
(pH <6)
gastric juices, acid springs

Question 10

Neutrophiles

Answer 10

prefer neutral environments (pH >5.5 or <8)
blood, bacteria, WBC

Question 11

Alkaliphile

Answer 11

prefer basic environments (pH>_8)
water, seawater, natural soil

Question 12

Obligate anaerobe

Answer 12

No O2, it is toxic
found in large intestines and deep water

Question 13

Aerotolerant anaerobe

Answer 13

No O2 use, it is irrelevant therefore they are found anywhere

Question 14

obligate aerobe

Answer 14

requires O2 so it needs atmospheric exposure
surface of the soil, human respiratory tract

Question 15

Microaerophile

Answer 15

requires less O2 and are found a bit below the surface
Found in.soil aggregates and biofilms

Question 16

Facultative aerobe

Answer 16

can do with or without the presence of O2 so can be found anywhere

Question 17

1) Which type of organism would you expect to find growing in an acidic hot spring at Yellowstone National Park?
a. Halotolerant thermophile
b. Acidophilic hyperthermophile
c. Psychrophilic microaerophile

Answer 17

b

Question 18

Specialized adaptations of psychrophiles include what?

Answer 18

1. production of flexible proteins (a-helices) that require less energy to function
2. More unsaturated and short-chain membrane lipids to maintain membrane fluidity
3. production of cryoprotectants and anti-freeze proteins

Question 19

Specialized adaptations of hyperthermophiles and thermophiles include what?

Answer 19

1. heat stabilization of enzymes through increased ionic bonding or production of heat-stable solutes
2. more saturated and long-chain membrane lipids to reduce membrane fluidity.

Question 20

Specialized adaptations of nonhalotolerant include what?

Answer 20

to counteract the hypotonic environment. In hypotonic environments, cells survive by secreting solutes into the external environment to balance osmotic gain of water. Membrane channels are mechanosensitive and are activated when osmotic gain of water causes the cell to become turgid.

Question 21

: Describe the relationship between external pH and internal pH. What does this relationship imply about the physiology of acidophiles and alkaliphiles?

Answer 21

As the external pH changes, the internal pH remains constant with very minor changes. This means that it isn’t that there are mechanisms in place to help maintain the pH homeostasis that internal cellular processes need to function

Question 22

What do specialized adaptations of acidophiles include?

Answer 22

1. Production of proton-impermeable membrane lipids
2. increased export of protons
3. increased proton-consuming reactions in the cytoplasm.

Question 23

What do specialized adaptations of alkaliphiles include?

Answer 23

1. incorporation of acid residues into their cell walls
2. ) increased reliance on sodium-motive forces in place of proton-motive forces.

Question 24

Oxygen adaptations

Answer 24

Oxygen byproducts (e.g., superoxide, hydrogen peroxide) are highly reactive and can severely damage cells, so organisms living in aerobic environments must have specialized enzymes to detoxify these reactive oxygen species (ROS)

Question 25

4) Which type of organism would you expect to have an increased number of integral membrane proteins?

Answer 25

Alkaliphiles because they rely on the sodium motive forces for ion transport and to maintain pH homeostasis

Question 26

5) Which type of organism would you expect to have more cell membrane lipid adaptations? a. Obligate aerobes b. Acidophiles c. Thermophiles d. Both B and C

Answer 26

Both acidophiles and thermophiles. Acidophiles need to modify their membranes in order to block proton entry. Thermophiles need to adapt their lipids for heat stability

Question 27

Sterlization

Answer 27

A physical antimicrobial method. Autoclaves use high temperature and high pressure to sterilize objects and liquids Pasteurization uses high temperatures long enough to kill the most heat-resistant pathogen known

Question 28

Radiation

Answer 28

A physical antimicrobial method. Radiation is used to decontaminate objects by disrupting DNA in living cells. Ionizing radiation (e.g., gamma rays) has more energy than non-ionizing (e.g., ultraviolet) radiation and is therefore better at decontamination of bulk objects rather than surfaces.

Question 29

Antimicrobial

Answer 29

A chemical antimicrobial method Broad-spectrum chemicals can be used to control microbial growth by sterilization (e.g., ethylene oxide), disinfection (e.g., triclosan, pine-sol), antisepsis (e.g., alcohol), or sanitation (e.g., Lysol, bleach).

Question 30

Antibiotics

Answer 30

A chemical antimicrobial method Target-specific chemicals that inhibit specific bacterial processes (e.g., penicillin blocks cell wall synthesis, quinolones block DNA gyrase).

Question 31

Sterilants

Answer 31

Kill everything

Question 32

Disinfectants

Answer 32

Kill vegetative cells but not spores

Question 33

Sanitizers

Answer 33

reduces microbial load

Question 34

Antiseptics

Answer 34

kills or inhibits the growth of microbes on living tissues

Question 35

Phage therapy

Answer 35

Biological antimicrobial method Target specific bacteria of interest by infecting them with viruses that target bacteria (i.e., bacteriophage).

Question 36

Probiotics

Answer 36

Biological antimicrobial method Foods containing live microbial cultures (e.g., yogurt, buttermilk, sourdough). The major therapeutic outcomes of probiotics include: * Increased competition with pathogens * Direct antagonism with pathogens * Bioconversion of food to usable nutrients * Form a protective barrier on host surfaces * Reduced inflammatory response

Question 37

Prebiotics

Answer 37

Biological antimicrobial method Foods that contain specialized plant fibers that stimulate growth of healthy bacteria (e.g., dry chicory root, dry garlic, raw asparagus). The major therapeutic outcomes of prebiotics are similar to those of probiotics.

Question 38

6) In a scenario where a patient is suffering from a severe bacterial infection and traditional antibiotics are proving ineffective, which microbial control approach might be considered as an alternative treatment? a. Novel antibiotic discovery b. Phage therapy c. “[Bring] light inside the body, either through the skin or some other way.”

Answer 38

B

Question 39

7) A spa is looking to maintain a hygienic environment in its hot tubs to prevent the growth of harmful bacteria. Which microbial control method could be used to ensure water sanitation in recreational facilities? a. Probiotics b. Antibiotics c. Light exposure

Answer 39

C

Question 40

8) In a hospital setting, there is a need to sterilize surgical instruments to eliminate all forms of microbial life, including spores. What microbial control method would be most appropriate for this purpose? a. Autoclaving b. Treating with bleach c. Treating with ionizing radiation

Answer 40

A

Question 41

Specialized adaptations of halophile do what?

Answer 41

to counteract the hypertonic environment. In hypertonic environments, cells survive by importing compatible solutes—solutes that increase internal osmolarity without interfering with biochemical functioning (e.g., glycerol, KCl, glycine betaine, amino acids)—to balance osmotic loss of water