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bio 2051
chapter 5
61
Microbiology
Undergraduate 3
02/09/2012

Additional Microbiology Flashcards

 


 

Cards

Term
• Temperature
• Pressure
• Osmolarity
• pH
• Oxygen
Definition
Environmental factors that affect microbial growth
Term
minimum temperature
Definition
cellular processes slow; cytoplasmic membranes stiffen; harder to transport in and out of cell
Term
maximum temperature
Definition
- proteins start to denature
Term
• 0°C–20°C

• 20°C–45°C

• 40°C–80°C

• 65°C–113°C
Definition
psychrophiles

mesophiles

thermophiles

extreme thermophiles
Term
Chlamydomonas- “snow algae”
Definition
• Psychrophiles- found in constantly cold environments
Term
• Molecular adaptations of psychrophiles:
Definition
• Membranes have high content of unsaturated fatty acids – semi-fluid at low temperatures

• Proteins are more flexible compared to mesophiles or thermophiles
Term
• Cryoprotectants
Definition
can be used to preserve microbial cultures at low temperatures
Term
• 10% DMSO (Dimethylsulfoxide) & 10% glycerol
Definition
are commonly used in laboratories to preserve microbial cultures for long time in freezers
Term
mesophiles
Definition
• Found in warm-blooded animals & many terrestrial & aquatic environments.

• Examples- most organisms you are familiar with such as Escherichia coli (found in the human intestine)
Term
• Soils subjected to full sunlight

• Fermenting materials (compost)

• Hot springs
Definition
places thermophiles are found
Term
• Thermus aquaticus
Definition
a common hot spring thermophile. The heat stable DNA polymerase from this bacterium is mass-produced and used in laboratories to replicate DNA in a test tube
Term
molecular adaptations of thermophiles
Definition
• Membranes have a high content of saturated fatty acids – stable & functional at high temperatures

• Enzymes are heat stable - proteins are more rigid compared to mesophiles or psychrophiles
Term
heat shock response
Definition
• Occurs at high end of temperature range
• “Emergency” proteins produced
• Help keep proteins from denaturing
• Induced by many stressful conditions
Term
barophiles
Definition
• Adapted to high pressures
• Up to 1,000 atm
Term
• Barotolerant organisms
Definition
• Grow at high, but not very high pressure
Term
• Barosensitive organisms
Definition
• Die at high pressure
• Most “typical” bacteria, all mammals
Term
high; lower

low; high
Definition
• Water moves from areas of ____ water concentration to areas of _____ water concentration.

• Water moves from areas of ____ solute concentration to areas of ____ solute concentration.
Term
hypotonic
Definition
____ environment, water will move into cell
Term
hypertonic; plasmolysis
Definition
____ environment, water will move out of the cell and the cell will die of _____
Term
TRUE
Definition
no physical barrier that prevents cell from losing too much water if cell is in hypertonic environment. T/F
Term
cell wall
Definition
physical barrier that keeps cell at equilibrium in hypotonic environments for prokaryotes
Term
1. Pumping inorganic ions (K+) into the cell

2. Making or concentrating an organic solute (glycerol) in the cell.
Definition
• Some cells can increase solute concentration in cell to prevent too much water loss by:
Term
osmophile
Definition
organism that grows in high solute concentrations (hypertonic environments)
Term
halophiles
Definition
grow best in high salt habitats
Term
3%
Definition
__% salt concentration in ocean
Term
extreme halophiles
Definition
require high levels (15% to 30%) of salts for growth
Term
– Halobacterium salinarium
Definition
(requires 25% salt) lives in very salty lakes – HUGE amount of salt
Term
halotolerant
Definition
can survive at higher salt concentrations but grow best in absence of salt
Term
– Staphylococcus aureus
Definition
organism that's halotolerant
Term
hydrogen
Definition
pH relative to ____ ion
Term
weak
Definition
• ___ acids can pass through membranes very easily
Term
Thiobacillus
Definition
produces sulfuric acid
Term
acidophiles
Definition
• Fungi as a whole are usually mostly
Term
• Sulfolobus
Definition
double extremophile – thermophilic and acidophilic
Term
alkaline
Definition
Many species of Bacillus live in very ____ soils
Term
Proteases & lipases
Definition
• _____ made by alkaliphiles are mass-produced & used in household detergents.
Term
Spirulina
Definition
• – flamingos eat and become pink
Term
• Oxic environment

• Anoxic environment
Definition
O2 is present

no O2 present
Term
• Facultative aerobes
Definition
use O2 in respiration but can also grow in anoxic environments
• Ex. E. coli in large intestine
Term
• Obligate aerobe -
Definition
use O2 in respiration & require oxic environments for growth. Grow at atmospheric O2 levels (21%)
Term
• Microaerophile -
Definition
use O2 in respiration but require low O2 concentrations, 2-10%, (microoxic environments) to grow – use candle jar to grow
• Ex. Streptococcus pneumonia
Term
• Aerotolerant anaerobes -
Definition
do not use O2 to generate energy but can survive in the presence of it
Term
• Obligate anaerobes
Definition
can only grow in anoxic environments; may die if even minute amount of O2 is present
Term
reducing agent
Definition
• A ______ such as thioglycolate can be added to a medium to test an organism's requirement for O2
Term
aerobes
Definition
Culture medium must be oxygenated by shaking or bubbling air into the medium for these microorganisms
Term
Catalase, peroxidase, superoxide dismutase, superoxide reductase
Definition
Enzymes made by cells can neutralize toxic forms of oxygen.
Term
• Autoclave –
Definition
sterilizes using steam and pressure; Kills all bacteria (sterilizes)
Term
• “Cold sterilization” –
Definition
uses gases such as ethylene oxide in machine similar to autoclave
Term
• UV hood –
Definition
air is blown outward through a filter from the back and from edges of the hood so that the area inside the hood remains sterile once the UV light is turned off.
Term
ionizing radiation
Definition
• Causes breaks in DNA; breaks hydrogen bonds & disulfide bridges in proteins; used widely in medicine
Term
depth and membrane
Definition
2 types of filters used for filtration
Term
depth filters
Definition
ibrous sheets or mats made from a random array of overlapping paper, asbestos, or borosilicate

• Traps large particles from liquids & air
Term
membrane filters
Definition
• Thin sheets of polymers (cellulose); contain tiny holes of known size

• Act like sieves, trap particles on membrane surface; Ex - antibiotics
Term
• Nucleation track (nucleopore)
Definition
filters used for concentrating a liquid sample for view on the scanning electron microscope.
Term
• Disinfectants
Definition
Used to reduce microbial numbers on nonliving materia
• Bleach (chlorine), ethanol
Term
• Antiseptics
Definition
• Used to reduce microbial numbers on living tissues
• Betadyne (iodine), H2O2 (hydrogen peroxide)
Term
antibiotics
Definition
• Naturally occurring antimicrobial substances produced by microorganisms; selectively kills microbes; typically safe to be ingested (disinfectants and antiseptics are not)
Term
penicillin
Definition
• Many derivatives
• Blocks cell wall synthesis
• Growing bacteria lyse
– Slow-growing bacteria take longer to die
Term
1
Definition
less than __ % clinically useful antibiotics because of poor uptake or toxicity
Term
probiotics
Definition
• “Good” bacteria – ingest and they will take up space in digestive system so pathogens won’t have a place to live there
• Displace pathogens from tissues
Term
bacteriophage
Definition
• Viruses that infect bacteria
• Do not harm eukaryotes
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