Extremophiles

Question 1

Extremophiles

Answer 1

Microbes that grow in extreme environments

Question 2

Obligate aerobe

Answer 2

Need oxygen

Question 3

Where obligate aerobes would populate in a tube that was open at the top

Answer 3

The top of the tube

Question 4

Facultative anaerobe

Answer 4

Prefer oxygen

Question 5

Where facultative anaerobes would populate in a tube that was open at the top

Answer 5

More at top, but spread throughout

Question 6

Aerotolerant anaerobe

Answer 6

Ignore oxygen

Question 7

Where aerotolerant anaerobes would populate in a tube that was open at the top

Answer 7

Throughout tube

Question 8

Obligate anaerobe

Answer 8

Oxygen is toxic

Question 9

Where obligate anaerobes would populate in a tube that was open at the top

Answer 9

At the bottom

Question 10

Microaerophile

Answer 10

Narrow band of growth at 2-10% oxygen

Question 11

Where microaerophiles would populate in a tube that was open at the top

Answer 11

2-10% oxygen: near top of tube

Question 12

Reactive oxygen species

Answer 12

Toxic products produced by reduction of oxygen

Damage microbes

Question 13

Examples of reactive oxygen species

Answer 13

Superoxide radical (O2-)
Hydrogen peroxide (H2O2)

Question 14

Superoxide dismutase

Answer 14

Enzyme that turns superoxide radicals into hydrogen peroxide and oxygen

Question 15

Superoxide dismutase reaction

Answer 15

O2- + O2- + 2H+ -> H2O2 + O2

Question 16

Catalase

Answer 16

Enzyme that turns hydrogen peroxide to water and oxygen

Question 17

Catalase reaction

Answer 17

H2O2 + H2O2 -> 2H2O and O2

Question 18

Can microbes without superoxide dismutase and catalase live in oxygen environments?

Answer 18

No

Question 19

20% of familial cases of ALS occur from a mutation in what gene?

Answer 19

SOD1: superoxide detoxifying gene

Question 20

Hyperthermophiles: what temperature can they grow at?

Answer 20

Above 80 degrees C

Question 21

Current record holder of extremophile temperature growth

Answer 21

122 degrees C

Question 22

Example of hyperthermophile

Answer 22

Pyrococcus furiosus (archaea)

Question 23

Thermophiles: temperature range

Answer 23

40-80 degrees C

Question 24

Example of thermophile

Answer 24

Thermos aquaticus (bacteria)

Question 25

Mesophiles: temperature range

Answer 25

20-45 degrees C | Not really extremophiles

Question 26

Example of mesophile

Answer 26

E. coli

Question 27

Psychrophiles: temperature range

Answer 27

0-20 degrees C

Question 28

2 examples of psychrophiles

Answer 28

``` Listeria monocytogenes (bacteria, food borne pathogen that grows under refrigeration) Chlamydomonas (eukarya, snow algae- red color in snow) ```

Question 29

How do thermophiles stabilize proteins in high heat environments?

Answer 29

``` Increased hydrogen and covalent bonds Molecular chaperones (proteins that bind and refold damaged proteins) ```

Question 30

How do thermophiles stabilize DNA in high heat environments?

Answer 30

Synthesize proteins to coat DNA

Question 31

How do thermophiles stabilize membranes in high heat environments?

Answer 31

Lipid monolayers with ether bonds

Question 32

Water activity: what is it, and what affects it?

Answer 32

Availability of water for cell growth | Solutes such as salt and sugars decrease availability of water to microbes

Question 33

Higher solute concentration, ____ water activity

Answer 33

Lower

Question 34

Hypotonic osmolarity: net water movement, level of extracellular solute concentration, example of environment

Answer 34

Net movement of water into cell Low extracellular solute concentration Fresh water lake or stream

Question 35

Isotonic osmolarity: net water movement, level of extracellular solute concentration

Answer 35

No net movement of water (same amount going out as coming in) Same solute concentration inside cell and out

Question 36

Hypertonic osmolarity: net water movement, level of extracellular solute concentration, example of environment

Answer 36

Net movement of water out of cell High extracellular solute concentration Dead Sea, Great Salt Lake, peanut butter

Question 37

Osmophiles

Answer 37

Microbes that can live in hypertonic environments

Question 38

Halophiles

Answer 38

Osmophiles that live in high salt environments

Question 39

Examples of halophiles

Answer 39

Halobacterium (archaea) | Staphylococcus (bacteria)

Question 40

Where staphylococcus can be found

Answer 40

Human skin

Question 41

What is used to isolate staphylococcus?

Answer 41

Mannitol salt agar

Question 42

Compatible solutes

Answer 42

Synthesized or obtained from environment by halophiles in order to keep osmotic concentration of cytoplasm above that of habitat (enable halophiles to live in high salt environments)

Question 43

Acidophiles

Answer 43

Microbes that grow at low pH

Question 44

Alkaliphiles

Answer 44

Microbes that grow at high pH

Question 45

E. coli can tolerate what range of pH?

Answer 45

2-9 (10 million fold difference)