Chemical Reactions

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Chemical Reactions Enzymes

• - Means to write that information down.

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Chemical Reactions and Enzymes

• As we have seen living things are made of
  chemical compounds, but more importantly
  chemistry isnt just what life is made of,
  chemistry is also what life does.

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Chemical Reactions

• Chemical reaction is a process that changes one
  set of chemicals into another set of chemicals.
• The elements or compounds that enter into a
  chemical reaction are the reactants.
• The elements or compounds produced by a chemical
  reaction are known as products.

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Energy in Reactions

• Energy is neither created nor destroyed,
  therefore energy is released or absorbed whenever
  chemical bonds form or are broken.
• Chemical reactions that release energy often
  occur spontaneously. Chemical reactions that
  absorb energy will not without a source of energy.

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Activation Energy

• Do all reactions occur spontaneously?
• If this were true what would happen to your
  textbooks?
• Will wood burn only if you light it with a match.
• Chemists call the energy that is needed to get a
  reaction started the activation energy
• Fig 219 (p. 50) shows, activation energy is a
  factor in whether the overall chemical reaction
  releases energy or absorbs energy.

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Enzymes

• Some chemical reactions that make life possible
  are too slow or have activation energies that are
  too high to make them practical for life.
• These reactions require catalysts or substances
  that speed up the rate of a chemical reaction.
• Catalysts work by lowering a reactions
  activation energy.

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Two paths will take you to the same end location.
Which one will take less energy to get there and
will happen faster?
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Activation Energy

• What significance do these energy changes have to
  do with living things?
• In order to stay alive, organisms need to carry
  out reactions that require energy.

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Enzymes

• Enzymes are special proteins that act as
  biological catalysts.
• Enzymes speed up chemical reactions that take
  place in cells.
• Enzymes are very specific, generally catalyzing
  only one chemical reaction.

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Enzymes

• For a chemical reaction to occur, the reactants
  must collide with enough energy so that existing
  bonds will be broken and new bonds will be
  formed.
• Enzymes provide a place where reactants can be
  brought together to react.
• The reactants of enzyme catalyzed reactions are
  known as substrates.

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The Enzyme/Substrate Complex

• Each protein (enzyme) has a specific shape, the
  substrate binds to the active site on the protein
  to help speed up the reaction.
• AKA lock and key

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Digestive Enzyme Basics
Enzymes - In Summary
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