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Chapter 4: Enzymes - Coggle Diagram
Chapter 4: Enzymes
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Activation Energy
Chemical reaction imagined as the process of rolling a huge stone (the reactant) up a hill, so it rolls down and breaks up into tiny pieces (products)
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Once the huge stone (reactant) is rolled over the hill, the rest of the reaction occurs and the huge stone rolls down the hill and breaks up into tinier pieces (the products are formed)
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EA Barrier
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Free energy of activation, the activation energy (EA)
Enzymes increase the rates of reaction by providing an alternative pathway with a lower activation energy
Enzymes do not affect the change in free energy (G), but instead they hasten reactions that would occur eventually
Digestive Enzymes
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Digestive enzymes like amylase and protease break the starch and protein down into maltose and polypeptide molecules respectively
More digestive enzymes like maltase and peptidase break the maltose and polypeptide down into glucose and amino acids respectively
These smaller molecules of glucose and amino acids can pass through the cell surface plasma membrane
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Hypotheses and Models
Lock and Key Hypothesis
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Substrate imagined as a lock, with a shape complementary to the enzyme, imagined as a lock
Substrate can fit into and bind to the active site, which has a specific shape, forming the enzyme-substrate complex
Once formed, the products no longer fit into the active site, so they escape into the surrounding medium, leaving the active site and enzyme free to receive further substrate molecules and take part in other reactions
Induced Fit Model
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Suggests that the active site does not necessarily begin with the exact shape complementary to that of the substrate
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Binding of the substrate to the active site induces a small conformational change in the shape of the enzyme
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