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57 Cards in this Set
- Front
- Back
Electron Transport Chain / Chemiosmosis
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NADH and FADH2 donate electrons to the ETC. The electrons flow down the chain of carriers, they lose energy which the cell captures in the form of ATP molecules. The final product is water (uses molecular oxygen)
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ETC Carriers, 3 different types of molecules (moving electron down chain and capturing energy)
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Flavorproteins
Cytochromoes Ubiquinoes |
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Flavoproteins
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contain flavin as redox coenzyme
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Cytochromes
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Use heme group (iron) to shuttle electrons
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Ubiquinones
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Only ones that aren't proteins
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What is the Chemiosmotic Mechanism? (capture energy from redox chain)
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Know about proton gradient on outside of membrane, chemical force pushing protons back into cell (Proton Motive Force) As proton passes through creates energy, for each 2 protons you get an ATP. See lecture 8 picture
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Summary of Cell Carbon Metabolism (Heterotropic Metabolism)
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- Total aerobic respiration yield is 38 ATP in prokaryote
- 36 ATP in eukaryotes - The bulk of the ATP is generated through the ETC. This is called oxidative phosphorylation |
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Photosynthesis
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used by many organisms to generate energy and carbon
- plants - many types of bacteria |
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Two distinct phases-light and dark reactions (capture of energy from light)
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1. Light Reaction: photophosphorylation
2. Dark Reactions: Calvin-Benson Cycle |
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Light Reactions: photophosphorylation
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- cyclic reaction uses no other inputs besides light energy
- Non-cyclic photophosphorylation generates oxygen gas, uses water |
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Dark Cycle: Calvin-Benson Cycle
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- Light-Independent or dark reactions
- End result is the production of glucose for use in cell metabolism - This is carbon "fixation" - Cost of CB cycle is 18 ATP and 12 NADPH |
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Energy and Carbon Sources
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All organisms need carbon and energy to survive-other things too, but these are the largest components of metabolism
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Carbon Sources:
- Autotrophy - Heterotrophy |
Autotrophy: fixation of carbon dioxide
Hetero |
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Energy Sources:
Chemoautotrophs Chemoheterotrophs |
look at slide
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Anabolism
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utilized to make amino acids, nucleotides, sugars, polysaccharides and lipids
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Microbial Metabolism: can be catergorized into 4 groups based on these carbon and energy regimes
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1. Photoautorophys
2. Photoheterotrophs 3. Chemoautotrophs 4. Chemoheterotrophs |
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Photoautotrophy
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- Organisms that ca derive engery from sunlight, carbon from CO2
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Oxygenic photoautotrophys
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Non-cylic photophosphorylation-release O2
- Cyanobacteria,a green algae |
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Photoheterotrophy
Purple non-sulfur bacteria |
Rhodopseudomonas
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Green non-sulfur bacteria
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Chloroflexus
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Photoheterotrophy: Organisms that use light for ____ sources, but are unable to fix _____
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- Energy; CO2
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Photoheterotrophy: Bacteria of this type must use organic ______ as a source of cell material
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- Carbon
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Chemoautotrophs:
Instead of using light, these microbes use ______ _____ reactions as sources of energy |
- inorganic redox
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Chemoautotrophs: are able to fix _____, but need a source of energy
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- CO2
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Chemoautotrophs: to gain energy, the bacteria ______ these compounds-often use ___ as the Terminal electron acceptor
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- oxidize; O2
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Chemoautotrophs: have many different possible sources of energy, not using glucose for their source, must be autotrophic
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- (sulfur compounds) Beggiatoa,
- (Ammonia) Nitrosomonas, - (Hydrogen gas) Hydrogenomonas, - (Ferrous Iron) Thiobacillus ferrooxidans |
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Lithotrophy
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- Uses inorganic chemistry to acquire energy (rock-easters)
- Ex: oxidize hydrogen sulfide (vent tubeworm associated bacteria), oxidize iron (Shewanella oncidensis) |
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Chemoheterotrophs:
Organsism that use organis carbon compounds as sources of both _____ and _______ |
- Carbon and energy
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Chemoheterotrophs: All _____ fall into this category
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Pathogens
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Chemoheterotrophs: A ____ is an organism that uses dead organism material for nutrients
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Saprophyte
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Chemoheterotrophs: ______ is an organism that feeds off of living material
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Parasite
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Microbial Growth: Bacterial growth is the ____ of bacterial cells by _____ _____
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division; binary fission
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Bacteria in a liquid broth culture can grow to very _____ _______
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High Densities
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Bacteria on an agar plate can grow to form _______
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Colonies
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Schematic Representation of Biofilm 4 stages
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1. Association
2. Adhesion 3. Microcolony formation 4. Biofilm formation |
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Conditions for Growth: Bacterial growth is dictated by the physical environment in which the organisms find themselves
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- Temperature
- Nutrients - pH - Pressure |
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These conditions will determine the specific ____ _____
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Growth Rates
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Temperature Effects
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- Each species grows in a temperature range with a max, mix, and optimal temperature
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pH can effect bacterial growth
Bacteria will grow with a pH optimum, typically in the range from __-__ |
5-9 (mildly acidic to mildly basic)
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Acidophiles are _____ that thrive under acidic condition
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Microbes
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Microbes have been isolated from coal mine drainage water than can survive ph __
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pH 1 (strong acid)
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Halotolerance (osmotolerance)
Most bacteria can tolerate salts at concentrations up to about ___% - plasmolysis at higher concentrations |
2%
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Bacteria such as staphylococci are mildly halotolerant (up to __-__%)
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10-15%
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Obligately halophilic organisms may require ___% salt to survive
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30% is required!
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Nutrients Requirements: To grow bacteria in the lab we can use a variety of nutrient media. We may define the medium in terms of exactly what nutrients are in it. We might use an undefined medium, for example sheep's blood and tryptone (enyzmatic digest of beef)
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In either case, we know that certain elements are required for growth
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Major Nutrients:
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- Carbon
- Nitrogen - Sulfur and Phosphorus |
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Micronutrients:
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- Organic trace elements (i.e. FAD, NAD, CoA)
- Many enzymatic functions require certain inorganic (Iron, Copper, Zinc) trace elements |
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Oxygen is not a nutrient, Oxygen is a toxic in molecular forms
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- Bacterial use enzymes to detoxify various reactive oxygen forms-hydrogen peroxide, free radicals
- Superoxide dismutase, Catalase |
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Bacterial Response to Oxygen: Obligate aerobes
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cannot grow in the absense of exygen
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Facultative Anaerobes
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Grow using fermentation pathways in the absense of O2
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Microaerophiles
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grow only in the presence of small concentrations
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Aerotolerant
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can survive in the presence of oxygen, but cannot grow
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Obligate anaerobes
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are killed by oxygen radicals generated in cells in the presence of 02
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Aerobic v. Anaerobic Growth
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Aerobic growth is easier
- Incubator for constant temperature Anaerobic: need airtight chamber, obligate anaerobes are killed by exposure to any oxygen, need to add reducing agent |
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Defined v. Undefined Media
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Nutrient Broth: if you wants lots of bacteria
Defined E. Coli medium: i.e. to what extent is this medium able to extract phosphate, manipulate details of growth, growth rates in response to change |
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Anaerobic Jar
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- Sucks out oxygen, and get very low oxygen, not total absence of oxygen
- Glove Box total lack of oxygen |
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Other special growth environments
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- Some bacteria can only grow in animal cells, and then infect the animal cells
- Mycobacterium leprae is grown in armadillos (natural hosts) |