4357474
Description
Flashcards by Samantha Scruggs, updated more than 1 year ago
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Created by Samantha Scruggs
about 8 years ago
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| Question | Answer |
| catabolism vs anabolism | catabolism - oxidative (often) energy producing. e.g., carbohydrates, lipids and proteins turned into ATP, NADH and NADPH anabolism - synthesis of macromolecules: muscle contraction, active ion transport, thermogenesis. Produces ADP + Pi, NAD+ and NADP+ |
| ATP | adenosine 5'-triphosphate - a purine (adenine) nucleotide in which adenine is linked by a glycosidic bond to D-ribose. 3 phos groups are esterified to the 5 position of the ribose moiety. The 2 terminal phosphoryl groups are energy-rich phospho-anhydride bonds or high energy bonds. Chelated with a divalent metal cation such as magnesium under physiological conditions |
| NAD+ and NADPH in catabolism and anabolism | catabolism is oxidative because carbons in carbs, fat and protein are in partially or highly reduced state. Reducing equivalents are transferred to NAD+ to form NADH. Then this goes to electron transport chain to O2 as the e- acceptor. These are exergonic and produce ATPs in oxidative phosphorylation in the electron transport chain. In anabolism, reducing power is provided by NADPH to form complex molecules such as fats. |
| thermodynamics | first law of thermodynamics - energy cannot be created or destroyed, only converted from one form to another. second law of thermodynamics - entropy (S) indicates the degree of randomness in a system; it is the energy that is unable to perform work. All processes tend to progress toward a situation of maximum entropy. Impossible to quantitate as systems rarely in equilibrium with surroundings. |
| Gibbs free energy | the free energy of a system is that portion of the total energy that is available for useful work. |
| equilibrium, exergonic, endergonic | If change in G is 0, the process is in equilibrium. Any process that has a negative change in G proceeds spontaneously toward equilibrium in the direction written, in part, due to increase in entropy. This process is EXERGONIC. A positive change in G will proceed spontaneously in the reverse direction. Energy must be applied to allow it to proceed toward equilibrium. This process is ENDERGONIC. ENDERGONIC - POSITIVE CHANGE G EXERGONIC - NEGATIVE CHANGE G (G values do not predict speed of reactions) |
| equilibrium constant | If K is less than 1, the reaction is endergonic and Change G0 is positive. if K is greater than 1, the reaction is exergonic and change G0 is negative. |
| standard free energy change (Change G0') | Change G0' represents the free energy available in a reaction when substrates and products are present at 1 M concentrations. |
| free energy change must be ____ for the reaction to continue. | Negative. Any 1 enzymatic reaction can be positive if the overall reaction is negative. Example. In glycolysis, various reactions either have positive Change G0' values or close to zero, whereas other reactions have large and negative Change G0' values which drive the pathway. The sum, however, must be negative for the pathway to be thermodynamically feasible. |
| resonance forms | The more possible resonance forms in which a molecule can exist stabilize that molecule. Fewer resonance forms exist for high energy bonds, like in ATP, which makes the arrangement energy rich. |
| The mitochondrial electron carriers are grouped into four large complexes. | Complex I, NADH-ubiquinone oxidoreductase catalyzes transfer of electrons from NADH to ubiquinone (UQ) or coenzyme Q (CoQ) Complex II, succinate-ubiquinone oxidoreductase or succinate dehydrogenase, transfers electrons from succinate to coneyzme Q; Complex III or cytochrome bc complex, ubiquinol-cytochrome c reductase, transfers electrons from ubiquinol (CoQH2 or UQH2) to cytochrome c; Complex IV, cytochrome c oxidase, transfers electrons from cytochrome c to O2. ATP synthase, or complex V, uses energy of the electrochemical gradient for synthesis of ATP. |
| flavoproteins | Complexes I-IV contain flavoproteins, which contain tightly bound FMN or FAD and can transfer one or two electrons. |
| cytochromes | part of complexes I-IV: b, c1, c, a and a3 transfer one electron from Fe 2+ of heme |
| iron-sulfur proteins | part of complexes I-IV; contain bound inorganic Fe and S and transfer one electron |
| Complex IV micronutrient | copper - in complex IV (cytochrome c oxidase) transfers one electron. |
| Complex I | Complex I, most complicated in mitochondria, transfers electrons from NADH to coenzyme Q (ubiquinone) coupled with transport of 4 protons across membrane. Contributes to proton motive force required for synthesis of ATP. L-shaped structure with long hydrophobic arm localized in the membrane and peripheral hydrophilic arm protruding into mitochondrial matrix. Electrons transferred to FMN, flavin mononucleotide which is tightly bound to a sub-unit in the hydrophilic arm. The electrons are then transferred one at a time via a series of FeS centers, of both the 2Fe2S and 4Fe4S types, located in different subunits of hydrophilic arm. |
| Complex I picture | |
| Complex II | succinate-ubiquinone oxidoreductase or succinate dehydrogenase subunit contains FAD bound to histidine, and subunit with three iron-sulfate centers, and two hydrophobic proteins. Oxidizes succinate to fumarate. Two e- and Two H+ transferred to FAD FADH2 transferss e- to ubiquinone via FeS centers. No gain in free energy accomplished. |
| Complex II picture | |
| Other mitochondrial flavoprotein dehydrogenases | other mito dehydrogenases feed electrons into the electron transport chain at the level of ubiquinone. glycerol-3-phosphate, formed from glycerol released by hydrolysis of triacylglycerols or by reduction of dihydroxyacetate phosphate produced during glycolysis, is oxidized by glycerol 3 phosphate dehydrogenase. |
| glycerol 3 phosphate dehydrogenase image | |
| Acyl CoA dehydrogenase | flavoprotein that catalyzes the first step in B-oxidation of fatty acids, transfers electrons from fatty acyl CoA to FAD to form FADH2, which then transfers electrons to ETF (electron transferring flavoprotein). Electrons are transfers from EFT to EFT-ubiquinone oxidoreductase which transfers electrons directly to ubiquinone in the inner membrane. |
| Complex III | cytochrome bc1 complex catalyzes transfer of two electrons from ubiquinol to cytochrome c with translocation of four protons across the membrane. 11 subunits of which 3 have prosthetic groups that serve as redox centers - cytochrome b (two hemes), cytochrome c1 (one heme), Rieske iron-sulfur protein which contains a 2Fe2S cluster pear-shaped with large domain protrudnig 75 A into mito matrix and smaller domain containing head of Rieske and cyto c protruding into intermembrane space. |
| complex III image | |
| cytochromes | proteins containing a heme group tightly bound to the protein. iron in heme of cytochrome is alternatively oxidized (fe3+) or reduced (fe2+) as it functions in the transport of electrons. a b and c on the basis of the alpha band of their absorption spectrum and the type of heme group attached to the protein. |
| cytochrome b | iron-protoporphyrin IX - same as found in hemoglobin and myoglobin; however, these hemes are buried in the membrane and cannot bind O2 |
| cytochrome c | contain heme c that is covalently bound to two cysteine residues of the protein via thioether linkages involving vinyl side chains of protoporphyrin IX |
| cytochrome a | contain heme a, a modified form of protoporphyrin IX in which a formyl group and an isoprenoid side chain have been added. |
| Complex IV | transfers electrons from cytochrome c to O2, the terminal electron acceptor, to form water coupled to translocation of protons across the membrane. consist of 13 subunits with two cytochromes a and a3. two copper centers known as CuA and CuB nuclear DNA part which is regulatory |
| complex IV picture |
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