Activation energy the amount of energy it takes to start a reaction For any

Activation energy the amount of energy it takes to

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Activation energy - the amount of energy it takes to start a reaction - For any reaction to start its going to need energy. Clicker: Enzymes speed up reactions by lowering the activation energy. Clicker: will an enzyme change the deltaG of a reaction? No How Enzymes Work: - Substrate : the reactant that the enzyme is acting on - Active Site : the part of the enzyme that binds to the substrate - Once bound, the enzymes and substrate form a complex called enzyme-substrate complex
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- The substrate is then converted to products, and the products are released from the enzyme - One big cycle that keeps repeating Clicker: Factors that can affect enzyme activity Changes in pH, temp, competitive inhibitors, noncompetitive Common temp in bodies for enzyme optimization: 37C or 98F Competitive Inhibitors - Reversible - Compete with substrate for the active site on the enzyme Clicker: the effect that competitive inhibitors would have on enzymes activity would be to decrease enzyme efficiency Noncompetitive inhibitors - Do not directly compete with the substrate molecule - Impede enzyme activity by binding with another part of the enzyme - This causes the enzyme to change its shape Clicker: which inhibitor is more likely to be chemically similar to the normal substrate molecule? Competitive Regulation of enzyme activity helps control metabolism - Allosteric site: Specific binding site, but not the active site - This binding changes the shape of the enzyme - Either stimulates or inhibits enzyme activity, based on new shape How can the cell “turn off” the enzymatic pathway? - Feedback inhibition: Increases the efficiency of the pathway by turning it off when the end product accumulates in the cell - End product “switches off” the pathway by binding to the allosteric site Enzyme= ends in –ase 10/2/17 Evolutionary History of Life - Phylogeny: evolutionary history of a species or a group of related species - Systematics: A discipline that focuses on classifying organisms and their evolutionary relationships - Taxonomy: an ordered division of organisms into categories based on a set of characteristics used to access similarities and differences Binomial Nomenclature - Carolus Linnaeus - Example: Canis familiari - Hierarchical classification - Each categorization at any level is called a taxon 3 domains: archaea, eukarya, bacteria Phylum Class Order Family
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Genus Species Phylogenetic Trees - Depict hypothesis about evolutionary relationships - Reflect the hierarchical classifications of groups nested within more inclusive groups *** Homologous structures : similarities due to shared ancestry Convergent evolution: When two organisms develop similarities as they adapt to similar environmental challenges - Not because they evolved from a common ancestor Analogous structures: the likenesses that results from the convergent evolution Concept 26. 3: Shared characters are used to construct phylogenetic trees - Once homologous characters have been identifying, they can be used to infer a phylogeny - Cladistics groups organisms by common descent -
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  • Spring '19
  • RON DORN

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