Topic 9

Question 1

What are microaerophiles?

Answer 1

organisms that grow at low oxygen levels

Question 2

Rank mesophiles, hyperthermophiles, psychrophiles, and thermophiles in order of greatest to smallest living temperature.

Answer 2

hyperthermophiles, thermophiles, mesophiles, and psychrophiles

Question 3

What are the cardinal temperature of an organism?

Answer 3

the minimum, optimum, and maximum temperature

Question 4

What is the heat-shock response?

Answer 4

rapid temperature change during growth that activates stress response

Question 5

What are microbial chaperones?

Answer 5

protein products that maintain protein shape and enzymes that change membrane composition

Question 6

What is water activity?

Answer 6

a measure of how water is available, high [solute] have low water activity

Question 7

What water activity do most bacteria require?

Answer 7

greater than 0.91

Question 8

How is osmolarity and water activity related?

Answer 8

inversly

Question 9

How do hypertonic media minimize osmotic stress?

Answer 9

compatible solutes binds to water so it can’t leave

Question 10

How do hypotonic media minimize osmotic stress?

Answer 10

turgor pressor and mechanosensitive channels that leak water out

Question 11

How much salt do halophiles require?

Answer 11

2 to 4 M NaCl (10 - 20%)

Question 12

What are aerotolerant anaerobes?

Answer 12

can grow in O2 but don’t need it

Question 13

What are facultative anaerobes?

Answer 13

can live with or without oxygen