lecture 3

Question 1

cardinal temperatures

Answer 1

the minimum, maximum, and optimum growth temperatures for a given organism

Question 2

mesophile

Answer 2

an organism that grows best at temperatures between 20 and 40°C

Question 3

psychrophile

Answer 3

an organism with a growth temperature optimum of 15°C or lower and a maximum growth temperature below 20°C

Question 4

psychrotolerant

Answer 4

capable of growing at low temperatures but having an optimum above 20°C

Question 5

thermophile

Answer 5

an organism whose growth temperature optimum leis between 45 and 80°C

Question 6

hyperthermophile

Answer 6

a species of bacteria or archaea whose growth temperature optimum is 80°C or greater

Question 7

pH

Answer 7

negative logarithm of the hydrogen ion (H+) concentration of a solution

Question 8

neutrophile

Answer 8

an organism that grows best at neutral pH, between pH 5.5 and 8

Question 9

acidophile

Answer 9

an organism that grows best at low pH, typically below pH 5.5

Question 10

alkaliphile

Answer 10

an organism that has a grow pH optimum of 8 or higher

Question 11

water activity (Aw)

Answer 11

the ratio of the vapor pressure of air in equilibrium with a solution to the vapor pressure of pure water

Question 12

halophile

Answer 12

a microorganism that requires NaCl for growth

Question 13

halotolerant

Answer 13

a microorganism that does not require NaCl for growth but can grow in the presence of NaCl, in some cases, substantial levels of NaCl

Question 14

extreme halophile

Answer 14

a microorganism that requires very large amounts of NaCl, usually greater than 10% and in some cases near saturation, for growth

Question 15

osmophile

Answer 15

an organism that grows best in the presence of high levels of solute, typically a sugar

Question 16

xerophile

Answer 16

an organism that is able to live, or that lives best, in very dry environments

Question 17

compatible solute

Answer 17

a molecule that is accumulated in the cytoplasm of a cell for adjustment of water activity but that does not inhibit biochemical processes

Question 18

aerobe

Answer 18

an organism that can us O2 in respiration; some require O2

Question 19

microaerophile

Answer 19

an aerobic organism that can grow only when O2 tensions are reduced from that present in air

Question 20

facultative

Answer 20

with respect to O2, an organism that can grow in either its presence or absence

Question 21

anaerobe

Answer 21

an organism that cannot use O2 in respiration and whose growth is typically inhibited by O2

Question 22

aerotolerant anaerobe

Answer 22

a microorganism unable to respire O2 but whose growth is unaffected by it

Question 23

obligate anaerobe

Answer 23

an organism that cannot grow in the presence of O2