Lab 14: Effect of Temp. on Bacterial Growth

Question 1

Bacteria have a range of optimal temperatures at which they can grow, which causes the most rapid growth?

Answer 1

optimum temp.

Question 2

define a psychrophile

Answer 2

organism with an optimal growth temp. range of -5 degree C to 20 degrees C

Question 3

define mesophiles

Answer 3

organisms with an optimal growth temp. range at 20 degrees C to 50 degrees C

Question 4

define thermophiles

Answer 4

organisms with an optimal temp. growth range of 50 degrees C to 80 degrees C

Question 5

define hyperthermophiles

Answer 5

organisms with an optimal temp. range of > 80 degrees C

Question 6

describe the effect of elevated temperatures on proteins

Answer 6

they are denatured by any temp. above their maximum growth range
- it is irreversible
- the proteins unfolds an will NEVER return to its original shape

Question 7

describe the effect on organisms in temperatures below the minimum growth range

Answer 7

-proteins are not denatured but the enzymes do NOT work properly
-the cells survive but CANNOT grow and reproduce

Question 8

which organism produced a pigment?

Answer 8

S. marcescens

Question 9

what was the optimal temp. for pigment production in S. marcescens?

Answer 9

25 degrees C

Question 10

what was the optimal temp. for growth of E. coli?

Answer 10

37 degrees C

Question 11

What type of cellular molecules regulate growth and pigmentation?

Answer 11

proteins and enzymes (responsible for catalyzing chemical reactions)

Question 12

what is a more accurate way to determine the optimal temps. for pigment formation & growth?

Answer 12

the use of a spectrometer

Question 13

what is the optimal growth temp, for human pathogens?

Answer 13

around 37 degrees C