2–4 Chemical Reactions and Enzymes Photo Credit: Richard Megna/Fundamental Photographs Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Chemical Reactions Chemical Reactions A chemical reaction changes a set of chemicals into another form. Anabolic- puts together Catabolic- takes apart Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Chemical Reactions The elements or compounds that enter are reactants. The elements or compounds produced are products. Reactants (reaction happening) Products Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Energy in Reactions Activation Energy The energy that is needed to get a reaction started (like a spark starting a fire) Chemical reactions that release energy often occur spontaneously. Chemical reactions that absorb energy will occur only with a source of energy. The peak of each graph represents the energy needed for the reaction to go forward. The difference between this required energy and the energy of the reactants is the activation energy. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Enzymes Catalysts Chemical reactions that make life possible are slow or have high activation energy. Catalysts – speed up reactions by lowering activation energy. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Enzymes Enzymes- the catalysts inside you body - - Speed up chemical reactions in cells. Are recycled, don’t get used up. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Enzyme Action Substrates – what the enzyme works on Active Site – where the substrate and enzyme connect like a lock and key Enzymes can connect substrates together or take them apart Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Enzymes are Protein They do their job because of their shape. They only work with substrates that fit. If they change shape they stop working Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Enzyme Action Enzymes can be affected by any variable that influences a chemical reaction. pH values – too acidic or basic changes shape Changes in temperature- Hot changes shape, cold slows down reactions Enzyme or substrate concentrations- High concentration = fast, Low = slow Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 2–4 Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 2–4 The elements or compounds produced by a chemical reaction are known as reactants. enzymes. products. waste. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 2–4 The factor that prevents many energy-releasing reactions from occurring at relatively low temperatures is called catalytic energy. chemical bond energy. enzyme energy. activation energy. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 2–4 Which of the following can affect how well an enzyme can function? Temperature pH Level Concentration All of the above Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 2–4 Which of the following statements is true? All proteins are enzymes. All catalysts are enzymes. All enzymes are catalysts. All catalysts are proteins. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 2–4 Open-ended Why is the shape of the enzyme so important to its job within your body? Copyright Pearson Prentice Hall
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