Metabolic Pathways, Optimal Growth, and Sterilization Techniques Flashcards
Lectures 21-23
What is a Psychrophile?
Microorganism that grows well at low temperatures (<20 C)
What is a Mesophile?
Microorganism that grows well at mid-range temperatures.
What is a Thermophile?
Microorganism that grows well at high temperatures (45 C- 80 C).
What is a Hyperthermophile?
Microorganism that grows well at very high temperatures (>80 C).
What is a psychotolerant microorganisms?
Can grow at 0 C but prefer temperatures between
20 C- 40 C.
True or False: Above 65 C only eukaryotic life exists.
False: Above 65 C only prokaryotic life exists.
What is an Acidophile?
Grows best at a ph <6.
What is an Alkaliphile?
Grows best at a ph >9.
What is water activity (aw)?
Water availability: expressed in physical terms-
Defined as the ratio of vapor pressure of air in equilibrium with a substance or solution to the vapor pressure of pure water
Where does water want to go- to higher solute concentrations or lower solute concentrations? What does it want to produce by moving?
Water wants to go to the high solute concentrations to create turgor pressure.
What is a halophile?
Microorganism that grows well in a saline filled environment.
What is an extreme halophile?
Requires a 15-30% saline environment to grow.
What is a halotolerant microorganism?
A microorganism that can tolerate low water activity but grows best at lower solute concentrations.
What is an osmophile?
Grows well with a high sugar solute.
What is a xerophile?
Grows well in dry environments.
What do honey, jams, jellies, jerky, and salted cod all have in common?
Don’t have a lot of microorganisms growing in them due to lack of water activity and lack of nutrients.
What is an obligate aerobe? In which zone will it grow in a thioglycolate broth tube?
An organism that requires oxygen to live. It will grow only in the oxic zone at the top of the thioglycolate broth tube.
What is a strict anaerobe? Which zone will it grow in in a thioglycolate broth tube?
An organism that does not require oxygen to live and may by killed by it. It will grow only in the anoxic zone at the bottom of the thioglycolate broth tube.
What is a facultative aerobe? Which zone will it grow in in a thioglycolate broth tube?
An organism that can grow without oxygen but will use it when it is available. It will grow throughout the thioglycolate broth tube, but optimal growth occurs in the oxic zone where oxygen is present.
What is a aerotolerant anaerobe? Which zone will it grow in in a thioglycolate broth tube?
An organism that can grow in the presence and tolerate oxygen, but will not use it. It will grow well all throughout the thioglycolate broth tube, but will not use any oxygen.
What is a microaerophile? Which zone will it grow in in a thioglycolate broth tube?
An organism that can use oxygen when the oxygen’s levels are reduced from the air. It will grow only in the narrow band between the oxic and anoxic zone of the thioglycolate broth tube. It needs oxygen for aerobic respiration, but is killed by atmospheric levels of oxygen.
What are the toxic forms of oxygen that can be formed inside a cell?
Superoxide anion
Hydrogen peroxide
Hydroxyl radical
What are the enzymes present to neutralize the toxic forms of oxygen formed inside a cell? Which type of metabolic pathway lacks these enzymes?
Catalase Peroxidase Superoxide dismutase Superoxide reductase Obligate anaerobes usually lack these enzymes.
Which oxygen neutralizing enzymes have peroxide in their products?
Superoxide dismutase
Superoxide dismutase/ catalase in combination
Superoxide reductase
