Exam II Material - 30-nm fiber10-nm fiberExam II...

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Unformatted text preview: 30-nm fiber10-nm fiberExam II Material1.Metabolism1.Metabolism is the sum of all chemical activity in the cell – thousands of individual reactions1.1.Catabolism takes molecules (Food) and breaks them down1.1.1.Releases energy1.1.2.Final products used at precursors for new molecules1.2.Biosynthesis takes precursors and makes macromolecules1.2.1.Biosynthetic reactions require energy and get it from catabolic reactions2.How do we get the energy from our food to use in biosynthesis?2.1.Carbon and Hydrogen in food isn’t stable, so they’re reactive. They want to be CO2and H2O.2.2.A series of reactions breaks down large organic molecules like glucose to these molecules2.2.1.Carbon and Hydrogen are oxidized2.2.2.Spread out over more than 20 reactions to harness more of the energy2.2.3.Each reaction controlled by a specific enzyme3.Oxidation reactions involve removal of electrons3.1.Electros are transferred to a molecule which becomes reduced3.2.Oxidation and reduction reactions must balance3.3.Most electrons transferred in redox rxns are in the form of 2 H atoms3.4.Recipients of electrons in redox rxns are often special molecules associated with enzymes called cofactors or coenzymes3.4.1.Coenzymes are temporary carriers of energy3.4.2.2 main coenzymes in biological oxidation (accept 2 H+)3.4.2.1.NAD+ -> reduced to NADH (actually accepts 2 e-and 1 H+)3.4.2.2.FAD -> reduced to FADH23.4.3.Ultimately all the energy harnessed from the oxidation of food sources is used to make ATP (Adenosine TriPhosphate) which is the most common “currency” of energy in the cell3.4.3.1.Energy in ATP comes from the phosphate groups being unstable (negative charges repel)3.4.3.2.Hydrolysis of ATP yields ADP, an inorganic phosphate, and energy3.4.3.3.ATP ADP + PiΔG = -7 kcal/mol4.How does ATP drive energy-requiring rxns?4.1.ATP hydrolysis is coupled to the endergonic rxn4.2.The reaction that requires energy uses the energy provided upon hydrolysis of ATP4.2.1.Example:Glucose Glucose-6-PhosphateΔG = +3 kcal/molATP ADP + PiΔG = -7 kcal/molNet result of these coupled rxns:ΔG = -4 kcal/mol4.2.2.Coupled rxns often shown as:5.Cellular Respiration5.1.Gets the energy from food to ATP5.2.Breakdown of glucose to CO2and H2O5.3.Multiple reactions in 3 distinct pathways5.3.1.Glycolysis5.3.2.Pyruvate Oxidation & The Krebs (or Citric Acid) Cycle5.3.3.Electron Transport Chain & Oxidative Phosphorylation5.4.Glycolysis5.4.1.First pathway in breakdown of glucose5.4.1.1.“glycol” (sugar) + “lysis” (splitting)5.4.1.2.Starts with a 6-carbon sugar (glucose), ends with two 3-carbon molecules (pyruvate)5.4.2.Pathway is actually endergonic up to production of first 3-carbon molecules (uses cell’s store of ATP)5.4.3.OCCURS IN CYTOPLASM OF ALL LIVING CELLS5.4.4....
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Exam II Material - 30-nm fiber10-nm fiberExam II...

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