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How do autotrophs and heterotrophs differ in their source of carbon?
- Autotrophs- require inorganic source of carbon- use carbon dioxide
- heterotrophs- require an organic source of carbon- use carbohydrates, proteins, amino acids, lipids, fatty acids
How do phototrophs and cemotrophs differ in their source of energy?
- Phototrophs- use light for energy
- chemotrophs- use chemicals for energy
What are the four basic groups that all organisms can be described as in terms of their carbon and energy source? Examples
- Photoautotrophs- plants, algae
- photoheterotrophs- green nonsulfur and purple nonsulfur bacteria
- chemoautotrophs- hydrogen, sulfur
- chemoheterotrophs- aerobic respiration: most animals, fungi, protozoa, many bacteria
- anaerobic respiration: some animals, protozoa, bacteria
- fermentation: some bacteria, yeast
How do autotrophs and heterotrophs differ in their source of electron?
- Autotrophs- get electrons from inorganic sources
- heterotrophs- get electrons from organic compounds
Describe 5 ways cells protect themselves from toxic forms of oxygen
- Singlet oxygen- carotenoids detoxify
- peroxide anion- peroxide / catalase
- superoxide radical- superoxide dismutase
- hydroxyl radical- vitamin c and E
- Require O2 as final electron acceptor in metabolism
- increase O2 concentration
- cannot tolerate the presence of oxygen
- decrease O2 concentration
Can live and grow with or w/o oxygen
Do not use O2 in their metabolism but have some of the enzymes to detoxify it
- Require low O2 levels
Oxygen requirements of organisms by their growth in medium with an oxygen gradient
Describe the nitrogen requirements of microorganisms, including: what N is needed for, whether it is growth limiting, whether it comes from organic or inorganic sources, what is "nitrogen fixation" why do some organism reduce nitrate and can N be recycled?
- N is needed as part of amino acids and nucleotides (DNA & RNA) nitrogen bases
- growth limiting in environment
- can come from organic and inorganic
- some organisms can "fix" nitrogen gas from the air and convert to solid
- all cells recycle nitrogen froM their amino acids and nucleotides
Describe other chemical requirements of microorganisms
CHON- 95% o dry weight
Describe physical requirements including temperature, pH, osmotic pressure, and hydrostatic pressure
- Temperature- proteins require a specific 3D shape to function
- pH- measure of concentration of hydrogen ions, 7 acidic
- osmotic pressure- concentration of dissolved molecules, cells in freshwater gain H2O and shrivel
- hydrostatic pressure- barophiles live in H2O under extreme pressure, deep ocean hotsprings
Describe 3 different types of microbial associations
- Synergistic- each receives benefits that exceed those that would result if they lived apart
- symbiotic- live in close physical contact and become interdependent
- antagonistic relationship- one organisms harmsanother one
Describe the structure and function of biofilms
- plaque, very resistance and needs to be physically removed
- create micro environments
- protect individual cells from environmental stresses
- allow cells to concentrate and conserve digestive enzymes
Synergistic relationships, numerous types of microorganisms
What is the difference between liquid and solid medium?
- Liquid- broth
- solid- can grow colonies
What are the requirements for clinical sampling?
- Need to prevent contamination of the sample
- need to prevent infecting themselves
Describe two methods for obtaining pure cultures (streak plate and pour plate)
- Streak- sterile loop used to spread inoculum across surface of petri plata, inoculum gradually diluted to a point where colonies result from a CFU
- pour plate- CFU separated using series of dilutions , inoculum mixed with melted and cooled agar, then poured in petri plate and allowed to solidify
What is the function of agar?
Added to solidify
What organism. Has never been grown in any laboratory medium despite over a hundred years of trying?
- Traponema pallidum- syphillis organism
- majority of prokaryotes have never been grown in any culture medium
Compare "defined" medium with "complex" medium.
- Defined- exact chemical composition is known, synthetic medium
- complex- exact chemical composition unknown
What type of medium is "nutrient broth"?
What is "enriched" medium?
Blood may be added to provide growth factor like NADH and heme