G: Environmental Factors Influencing Growth part 2

Question 1

what are cardinal temp

Answer 1

the min temp, optimal temp and max temp for growth

Question 2

what happens at min temp

Answer 2

enzymatic rxns are too slow to support growth and membranes will solididy

Question 3

what happens above max temp

Answer 3

membranes will melt and proteins will denature

Question 4

what happens at optimal temp

Answer 4

closer to the max temp than min. bacteria have adapted their proteins and membrane to fn at diff temps

Question 5

what is the range btwn min and max temp

Answer 5

typically ~30 C

Question 6

What are psychrophile’s optimum temp and where are they found

Answer 6

~15 C. Found in polar ice and cold water

Question 7

What are psychotrophs’s optimum temp and where are they found

Answer 7

~25 C. common cause of food spoilage, can grow in the refrigerator at 4 C

Question 8

What are mesophile’s optimum temp and where are they found

Answer 8

for bacteria that live on body is ~37 C

for soil organism is ~30 C

Question 9

What are thermophile’s optimum temp and where are they found

Answer 9

~60 C. found in compost and hot tubs. bacteria used in yogurt production are thermophiles

Question 10

What are hyperthermophile’s optimum temp and where are they found

Answer 10

over 80 C. Archea found in hot springs and deep sea vents

Question 11

What does obligate aerobes require

Answer 11

O2 as termnal electron of ETC

Question 12

What does microaerophiles require

Answer 12

O2 as their ETC but are killed by atmospheric levels

Question 13

What does faculatative anaerobes require

Answer 13

grow best w/O2 as TEA but can grow w/out it

Question 14

What does aerotolerant anaerobes require

Answer 14

don’t use O2 for a TEA but aren’t killed by it

Question 15

What does obligate anaerobes require

Answer 15

don’t use O2 for a TEA and are killed by toxic oxygen derivatives

Question 16

What are toxic O2 derivatives

Answer 16

O2 is highly reactive moelcule and very electronegative

Question 17

what is symbol for superoxide radical

Answer 17

O2-

Question 18

what is symbol for hydrogen eperoxide

Answer 18

H2O2

Question 19

what is symbol for hydroxyl radical

Answer 19

H2O + OH.

Question 20

how are oxygen derivatives toxic

Answer 20

can damage cellular components by oxidizing them. kills cells

Question 21

Name 2 protective enzymes

Answer 21

supoeroxide dismultase and catalase/other enzymes

Question 22

What is the catalase test

Answer 22

add H202 to slide and then some bacteria. if bubbles visible, then catalase positive

Question 23

Give an example of aerotolerant and catalase -ive

Answer 23

Streptococcus spp.

Question 24

How can we grow microaerophiles and obligate anaerobes

Answer 24

grown in environment w/little or n O2. candle jar or jar with oxygen consumption system

Question 25

Some bacteria require higher CO2 levels than atmospheric levels. What can we use

Answer 25

candle jar or CO2 incubator