Control of Microbial Growth

Question 1

What are Extremophiles?

Answer 1

Organisms that normally live at extremes in environmental conditions

Question 2

When are Low Temperatures used to Influence rates of chemical reactions?

Answer 2

To preserve foods and cultures. Must add cryoprotectant to prevent ice crystals from disrupting membranes.

Question 3

When are High Temperatures used to Influence rates of chemical reactions?

Answer 3

To denature proteins and sterlize

Question 4

Psychrophiles

Answer 4

less than 15 degrees C

Question 5

Mesophiles

Answer 5

Between 15-45 C

Question 6

Thermophiles

Answer 6

Greater than 45 C

Question 7

Hyperthermophiles

Answer 7

Greater than 80 C

Question 8

Acidophiles

Answer 8

Acidic Ph. less than 6

Question 9

Alkiliphiles

Answer 9

Basic pH, above 9

Question 10

Do all microbes require liquid water for growth and reproduction?

Answer 10

Yes

Question 11

Osmotic Shock

Answer 11

When low solute concentrations outside cells cause water to diffuse in and the cells burst

Question 12

Osmophiles

Answer 12

Organisms able to live in high concentrations of sugar

Question 13

Halophiles

Answer 13

Organisms able to live in high concentrations of salt

Question 14

Barophiles

Answer 14

Organisms able to grow at high hydrostatic pressures

Question 15

What does Ionizing from Gamma or X Rays do to cells?

Answer 15

Induces formation of radical ions in cell which disrupt cell or polymerize molecules

Question 16

What do UV rays do to cells?

Answer 16

Forms pyrimidine dimers in DNA

Question 17

What do Visible spectrum wavelengths to do cells?

Answer 17

Photoautotrophs require different wavelengths. Non-photosynthetic pigments produced by some microbes prevent the formation of oxygen radicals

Question 18

What do Infrared rays to do cells?

Answer 18

Killing action caused by heat generation

Question 19

What are 5 requirements for cell growth?

Answer 19

Inorganic nutrients, carbon source, energy source, electron donor, electron acceptor