week 4 Flashcards
______ the total concentation of solute
a. diffusion
b. osmolarity
c. tonicity
d. hypertonicity
osmolarity
describes the concentration of permeable solutes:
a. diffusion
b. osmolarity
c. tonicity
d. hypertonicity
tonicity (eg. hypertonic, isotonic, hypotonic)
what describes an organism that grows well in high solute concentrations?
osmotolerant eg. yeast
organisms that require high salt concentrations and adjust internal osmolariy to survive conditions
a. extreme halophile
b. halophile
c. halotolerant
d. nonhalotolerant
halophiles - organisms that live in high salt concentrations
an organism capable of growing in or without the precense of salt
a. extreme halophile
b. halophile
c. halotolerant
d. nonhalotolerant
halotolerant
unable to tolerate high salt concentrations
a. extreme halophile
b. halophile
c. halotolerant
d. nonhalotolerant
non halotolerant
what are the 3 protective enzymes that aerobes produce? (enhance growth in oxygen environments)
super oxide dismultase
catalase
preoxidase
What are the reactive oxygen species created by oxygen that are toxic? (restrict growth in anaerobe conditions)
- superoxide
- hydrogen peroxide
- hydroxyl radical
used to describe an organism that can tolerate are adversley affected, survive at high tempuratures and live in less extreme environments
a. barotolerant
b.nonbarotolerant
c. barophillic
barotolerant
and organism that changes its membrane composition due to their adaptation of requiring pressure to live and thrive:
a. barotolerant
b.nonbarotolerant
c. barophillic
barophillic
Which of the following statements correctly compares defined medium and complex medium in microbiology?
A) Defined medium contains known quantities of specific nutrients, while confined medium restricts bacterial movement.
B) Defined medium limits bacterial growth to a specific area, while confined medium has unknown nutrient composition.
C) Defined medium has a precisely known chemical composition, while confined while confined medium has unknown nutrient composition.
D) Defined medium and confined medium are two terms for the same type of growth medium used in microbiology.
E) Defined medium is used only for eukaryotic cells, while confined medium is exclusively for prokaryotic organisms.
Defined medium has a precisely known chemical composition, while confined while confined medium has unknown nutrient composition.
uses antibiotics, high salt, and essential amino acids and sugars to grow a wanted/specific organism while inhibiting the growth of others
a. selective media
b. differential media
c. complex media
d. defined media
selective media
uses pH indicators, blood, and essential sugars to differentiate between organisms
.a. selective media
b. differential media
c. complex media
d. defined media
differential media
what is a bacteriostatic agent?
agent/antibiotic that stops cell growth only, growth continues when agent is removed. does not kill the cell
what is a bacterialcidal agent? what happens to the viable cell count and the total cell count after the agent is added?
agent that stops growth but keeps cells in tact (cells arent lysed)
viable cell count decreases
total cell count stays constant
what is a bacteriolytic agent? what does it do to viable cell count and total cell count after it is added.
bacteriolytic agents fully lyse the cell
this causes both viable and total cell count to decrease
Which of the following is a macronutrient required for microbial growth?
A) Zinc
B) Manganese
C) Carbon
D) Nickel
Carbon
Which of the following methods is most effective for sterilizing heat-sensitive liquids?
A) Boiling
B) Membrane filtration
C) Pasteurization
D) UV radiation
Membrane filtration
Membrane filtration is the preferred method for sterilizing heat-sensitive liquids because it removes microorganisms by physically filtering them out without applying heat, thereby preserving the integrity of the liquid. In contrast, boiling and pasteurization involve heat, which could degrade heat-sensitive components, and UV radiation may not penetrate deeply into the liquid to ensure complete sterilization.
Why is UV radiation limited as a sterilization method?
A) It does not generate enough heat to kill bacteria.
B) It penetrates too deeply, damaging beneficial microbes.
C) It only affects surface-level contaminants.
D) It requires oxygen to be effective.
It only affects surface-level contaminants.
What is a major difference between disinfection and sterilization?
A) Disinfection eliminates endospores, while sterilization does not.
B) Sterilization kills all viable organisms, while disinfection only kills pathogens.
C) Disinfection is more effective than sterilization.
D) Sterilization reduces microbial populations to safe levels but does not eliminate them.
Sterilization kills all viable organisms, while disinfection only kills pathogens.
What is the role of superoxide dismutase in aerobic microbes?
A) It directly produces ATP from oxygen.
B) It breaks down toxic oxygen species into less harmful molecules.
C) It prevents oxygen from entering the cell.
D) It generates free radicals to attack competing microbes.
It breaks down toxic oxygen species into less harmful molecules because superoxide dismultase is a protective factor released by O2
The ony physical technique that removes endospores
Sterilization
UV radiation kills bacteria by
A. Generating reactive oxygen species
B. Disrupting membranes
C. Causing thymine dimers
D. Introducing double stranded breaks in DNA
E. All of the above
Causing thymine dimers
Gamma radiation kills bacteria by
A. Introducing double stranded breaks in DNA
B. Generating reactive oxygen species
C. Disrupting membranes
D. All of the above
E. None of the above
Alll of the above
which chemicals kill spores?
-quatenary ammonium compounds
- phenolics
- alcohols
-halogens
- aldehydes
- hydrogen peroxide
- halogens (only at high concentrations)
- aldehydes
- hydrogen peroxide
skin antiseptic , causes skin damage , staining and allergies, oxidizes cell constituents and iodinates proteins:
-quatenary ammonium compounds
- phenolics
- alcohols
-halogens
- aldehydes
- hydrogen peroxide
halogens
chemical that oxidizes proteins lipids and sugars
-quatenary ammonium compounds
- phenolics
- alcohols
-halogens
- aldehydes
- hydrogen peroxide
hydrogen peroxide
prevents infection of living tissues from microorganisms. uses a chemical agent to kills or inhibits growth when applied to a surface
- sterilization
- disinfectant
- sanitization
- antiseptics
- chemotherapy
antiseptics
method that kills and inhibits internal and surface microorganisms
- sterilization
- disinfectant
- sanitization
- antiseptics
- chemotherapy
chemotherapy (antibiotics)
sterilization vs disinfectant
sterilization: zero cells, completely removes all viable organisms, kills spores
disinfectant: reduces microorganisms, removes pathogens but not spores
autoclaving vs pasteurization
autoclaving uses high moist heat that destroys spores, bacteria, fungi and viruses
low moist heat (pastuerization) slows spoilage and reduces organisms present and kills pathogens
