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51 Cards in this Set
- Front
- Back
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Metabolism is the...
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sum total of all the chemical rxns in the cell.
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The energy required to run cellular metabolism is derived from...
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redox reactions.
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Energy from redox rxns is used to make.....
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high energy phosphate bonds (ATP) and to generate ion gradients (usually PMF).
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The metabolic fueling pathways generate what for us?
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1. 12-13 carbon precursor metabolites
2. reducing power (NADH/NADPH) 3. cellular energy (ATP, PMF) |
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What pathways do respiring micro-organisms use?
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glycolysis, TCA, pentose phosphate, and Electron transport.
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What pathways do fermenting micro-organisms use?
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Glycolysis and some specific parts of the pentose phosphate and TCA.
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Electrons from redox rxns is released and used to make what?
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ATP and/or PMF
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Movement of electrons from glucose to NAD+/NADP+ generates...
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reducing power (NADH/NADPH) for biosynthesis, photosynthesis, and initial electron donor for respiration.
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List in order from better electron donors to better electron acceptors (Hint: 5 needed to know).
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1. CO2/glucose
2. NAD+/NADH 3. FAD/FADH2 4. Cytochromes (in the middle of the chart). 5. O2/H2O |
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Max energy extracted is related to...
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maximal change in E0'
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Aerobes extract maximal energy by using...
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O2as the final electron acceptor.
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How do microbes use electron donors and acceptors?
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they use many different ones to allow energy extraction in many different environments.
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Most common pathway used by most organisms in all domains.
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Glycolysis
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What happens as glucose is oxidized in glycolysis?
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electrons are transferred to NAD+, liberating energy that is trapped by making high energy P bonds. The P bond is then used to make ATP from ADP (substrate level phosphorylation).
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Staring points of glycolysis and ending products.
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Start with glucose and ATP. Make 2 ATP and 2 Pyruvate.
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What is the step between Glycolysis and the TCA cycle?
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Pyruvate is converted to Acetyl-CoA by making NADH
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What is the products of the TCA cycle?
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For fermenting microbes it depends because they only do certain parts.
For respiring microbes they generate GTP, NADH, and FADH2 |
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What happens to the NADH and FADH2 created via TCA cycle?
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diffuse to respiratory system on cytoplasmic membrane.
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What cycle interconnects with glycolysis?
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Pentose Phosphate pathway.
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Starting products & ending products for pentose phosphate pathway.
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1. 3 carbon sugars or 6 carbon sugars
2. 5 carbon sugars and NADPH |
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Pentose phosphate pathway provides precursors for.....
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aromatic AA's and vitamins.
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Alternative pathway to glycolysis.
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Entner-Doudoroff Pathway
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What does the Entner-Doudoroff Pathway produce?
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ATP, NADH, and NADPH
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Fermentation is associated with microbes that grow _______.
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anaerobically
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How is energy for fermentation generated?
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via SLPs (substrate level phosphorylation), not respiration
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What happens to the protons (H+) in fermentation?
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They build up inside the cell and have to be pumped out via ATP. NADH can also build up.
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Explain homolactic fermentation
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Fermenting microbes have to find a way to regenerate NAD+, so they change pyruvate to lactate (lactic acid) and get NAD+.
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What are some of the most common end products of Pyruvate via fermentation?
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1. removal of CO2 = ethanol
2. Isopropanol 3. Butanol 4. Butyrate 5. H2 + CO2 |
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What is respiration?
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the moveoment of electrons through an electron transport chain (captures and uses liberated energy for proton motive force)
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How are the electron transfer chains arranged?
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according to reduction potentials (most negative first). this allows electrons to move spontaneously.
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Energy liberated from ETC does what?
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pumps H+ out of the cell to make proton motive force
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aerobic respiration vs. anaerobic respiration
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in aerobic O2 is the final electron acceptor.
in anaerobic, they use non-oxygen final acceptors |
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FADH2 & NADH are produced _______ and diffused _______.
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in the cytoplasm; throughout the cytoplasm.
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For each listed, how does it accept/transfer electrons and protons?
Coenzyme Q (ubiquinone), FADH2, NADH, and Heme. Which are diffusible? |
Coenzyme Q a/t 2e-s and 2 H+s (not diffusible)
Same for FADH2 (diffusible) NADH a/t 2 e-s and 1 H+s as well as releases an H+ to the cytoplasm. (diffusible) Heme a/t 1 e- at a time. (not diffusible) |
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Energy from spontaneous redox reactions is used to...
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take up and then pump H+s out of the cell as electrons move between the 2 types of carriers.
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Tasks that occur via PMF
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make ATP for metabolism and photosynthesis, run flagella, active transport, etc.
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Explain the PMF of the last complex in ETC.
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Two parts to the complex:
F0: proton pump in membrane, it turns as H+ flows through F1: gamma (y) subunit of F1 interacts with F0, it also turns and synthesizes ATP Can work in reverse with ATP as an energy source. |
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Chemolithotrophs use a variety of __________ for respiration; typically in nutrient deficient environments.
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inorganic electron donors
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In chemolithotrophs respiration is usually....
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aerobic, but may be anaerobic. reverse respiration can happen to create NAD(P)H
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Phototrophs use special molecules like chlorophyll and bacteriochlorophyll that....
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absorb light energy and raise the reduction of e-s. They then flow through the ETC and make a PMF to make ATP. This occurs by photophosphorylation.
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Explain rhodopsin-based phototrophy.
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Microbes that contain bacteriorhodopsins create light driven H+ pumps that directly generate PMF's to create ATP (without chains).
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Chlorophylls are for ______ photosynthesis. Bacteriophylls are for ______ photosynthesis. All use ____ for the main part of the structure.
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oxygenic; non-oxygenic; Magnesium
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Accessory pigments surround the _______ and they....
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chlorophylls; absorb & transfer energy.
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In cyclic photophosphorylation what happens to the initial electron donor?
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it becomes the final acceptor, however electrons can be funneled in and out.
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Specifics of Cyclic Photophosphorylation.
(Hint: 4 things) |
1. Reduction potentials allow flow of e-s to make PMF
2. NAD+ can be reduced and leave the system. 3. Reverse e- flow can generate NADH/NADPH 4. These systems always use bacteriochlorophylls. |
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Specifics of noncyclic photophosphorlyation. (Hint: 5 things)
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1. Two photosystems are used.
2. Chlorophylls are used. (oxygenic, so oxygen is produced) 3. Light is absorbed and transfered to electrons in two phases. 4. A PMF is generated. 5. NADP+ is the final e- acceptor. Produces NADPH. |
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Members of the rhodopsin family all.....
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use light absorbed by retinal.
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In bacteriorhodopsins, how does the H+ get pumped out of the cell?
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light induced conformational changes.
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Some bacteriorhodopsins can act as _____.
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photoreceptors
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During aerobic metabolism, what is formed?
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reactive oxygen intermediates (O2- and H2O2)
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Two enzymes used in O2 utilization and their purpose.
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1. Superoxide dismutase (SOD) converts O2- into O2
2. Catalase converts H2O2 into O2 and H2O. |
