Microbiology Chapter 5 Study guide

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Metabolism
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The sum of all chemical reactions that take place in an organism Ability of an organism to obtain, convert and utilize energy
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Metabolic pathway
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A sequence of chemical reactions in a cell in which the end product becomes the substrate for the next reaction
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anabolism
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synthesis reactions simple molecules to complex dehydration (produce water) energy-using (endergonic)
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Catabolism
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breakdown reactions complex molecules to simple hydrolytic (use water) energy-releasing (exergonic)
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substrate
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a molecule upon which an enzyme acts
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phosphorylation
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addition of phosphate group
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Identify the components of an enzyme
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Many enzymes are made of protein alone Some enzymes are composed of: Protein portions (Apoenzymes) and Non-protein portions: Cofactors -inorganic ions (Fe, Cu,Zn) or Coenzymes -organic molecules (NAD+, NADP+, FAD) Holoenzyme -Complete active enzyme
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Function of an enzyme
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proteins that speed up a reaction by decreasing the ‘activation’ energy required to start a chemical reaction
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List the factors that influence the enzymatic activity
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Temperature pH Enzyme and substrate concentrations Presence of inhibitors Competitive Non-competitive
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Competitive Inhibitors
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Substances that block an enzyme’s active site Do not denature enzymes
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Non-competitive inhibitors
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Substances that alter an enzyme’s active site structure by binding to enzyme at allosteric stie
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Explain how feedback inhibition conserves the cell’s energy
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stops the metabolic pathway when final end product accumulates
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Summerize the four steps in aerobic respiration
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Glycolysis Preparatory step Krebs cycle Electron Transport Chain
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Glycolysis
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Glucose to pyruvic acid. 2 ATP, 2 Enzymes
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Prepatory step
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Pyruvic acid to acetyl-coA, 0 ATP, 2 Enzymes
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Krebs Cycle
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Acetyl-coA to electrons, 2 ATP, 8 Enzymes
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Electron Transport Chain
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12 electrons to ATP and H20, 34 ATP, 0 Enzymes
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Summarize the two steps in fermentation
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1) Glycolysis produces pyruvic acid as an end product (2 ATPs) 2) Conversion/transition produces a variety of end products – lactic acid (organic), acetic acid (vinegar) or CO2, ethanol (inorganic) (0 ATP) =total of 2 ATP only
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Explain how microbial metabolism is used to identify the microbes in the laboratory.
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Look for fermentation of pyruvic acid and evaluate the end products to determine which organism was fermented. (Test the presence of enzymes and detect the end product of metabolic pathways.)

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