Microbiology I

Question 1

Define psychrophiles and their optimal temperature

Answer 1

are organisms defined by their ability to grow at 0 degrees but have an optimum T of 10-15 degrees.

Question 2

describe Alkaliphiles including pH (min, optimum, max)

Answer 2

are those that grow best under alkaline conditions.

min 7.5, optimum 9.5, max 11.5

Question 3

describe Acidophiles including pH (min, optimum, max)

Answer 3

are microorganisms which grow at an optimum pH well below neutrality (7.0).

(min 1.0, optimum 3.0, max 4.5)

Question 4

Describe Microaerophiles

Answer 4

are organisms that grow if oxygen concentration is not too high, however, do not grow with no oxygen present.

Oxygen is required at levels below 0.2 atm.

Question 5

describe neutrophiles including pH (min, optimum, max)

Answer 5

are those which grow best at neutral pH.

min 5.5, optimum 7.0, max 8.5

Question 6

Define Psychrotrophs and their optimal temperature

Answer 6

grow at 0 degrees but display an optimum T in the mesophile range, nearer room temperature.

Question 7

Define Thermophiles and their optimal temperature

Answer 7

organisms with an optimum T between about 45 degrees and 70 degrees

Question 8

Describe Aerotolerant anaerobes

Answer 8

are bacteria with an exclusively anaerobic (fermentative) type of metabolism but they are insensitive to the presence of O2.

They live by fermentation alone whether or not O2 is present in their environment.

Question 9

Describe Facultative anaerobes/aerobes

or facultative aerobes

Answer 9

are organisms that can switch between aerobic and anaerobic types of metabolism. Under anaerobic conditions (no O2) they grow by fermentation or anaerobic respiration, but in the presence of O2 they switch to aerobic respiration.

Question 10

Describe Obligate aerobes

Answer 10

require O2 for growth; they use O2 as a final electron acceptor in aerobic respiration.

Question 11

Describe Obligate anaerobes

Answer 11

(occasionally called aerophobes) do not need or use O2 as a nutrient. O2 is a toxic substance to them and either kills or inhibits their growth. Obligate anaerobic prokaryotes may live by fermentation, anaerobic respiration, bacterial photosynthesis, or the novel process of methanogenesis.

Question 12

Describe Hyperthermophiles and their optimal and max. temperature

Answer 12

are some Archaea with an optimum T of 80 degrees or higher and a maximum T as high as 115 degrees.

Question 13

define Saprophyte

Answer 13

may refer to: Saprotrophs; organisms, particularly fungi, which obtain nutrients
directly from dead organic matter or wastes.

Question 14

define Lysozyme

Answer 14

is a naturally occurring enzyme found in bodily secretions such as tears, saliva,
and milk. It functions as an antimicrobial agent by cleaving the peptidoglycan component of
bacterial cell walls, which leads to cell death.