CHEMICAL REACTIONS

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CHEMICAL REACTIONS

• Process which changes one set of chemicals into
  another set of chemicals.
• Ex. Combining Iron (Fe) and Oxygen (O) to form
  Rust.
• Reactants - elements or compounds that enter into
  a chemical reaction
• Products - elements or compounds made by a
  chemical reaction.
• Bonds are broken in reactants and formed in
  products.

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CHEMICAL REACTIONS

• ALWAYS INVOLVE CHANGES IN ENERGY
• REACTIONS THAT RELEASE ENERGY SOMETIMES HAPPEN
  SPONTANEOUSLY
• REACTIONS THAT ABSORB ENERGY MUST HAVE A SOURCE
  OF ENERGY
• THE ENERGY NEEDED TO START A REACTION IS CALLED
  ACTIVATION ENERGY.

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CATALYSTS

• SUBSTANCES THAT SPEED UP RATE OF REACTION.
• WORK BY LOWERING THE ACTIVATION ENERGY.
• ENZYMES ARE PROTEINS THAT SPEED UP CHEMICAL
  REACTIONS IN CELLS. CAUSES THE REACTION TO TAKE
  PLACE BY LOWERING THE ACTIVATION ENERGY NEEDED.
• EX. CO2 H2O ? H2CO3
• Carbonic anhydrase

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SPEED OF REACTIONS

• LEFT ALONE MANY BIOLOGICAL REACTIONS WOULD HAPPEN
  TOO SLOWLY.
• Example of an enzyme
• CARBONIC ANHYDRASE CAUSES THE CHANGE INTO
  CARBONIC ACID TO HAPPEN QUICKLY.
• ENZYMES ARE SPECIFIC AND USUALLY ONLY CATALYZE
  ONE REACTION.

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ENZYME ACTION

• REACTANTS IN CHEMICAL REACTIONS MUST HIT WITH
  ENOUGH FORCE TO BREAK OLD BONDS AND FORM NEW ONES
• ENZYMES PROVIDE THE PLACE WHERE REACTANTS ARE
  BROUGHT TOGETHER REDUCING THE ENERGY NEEDED FOR
  THE REACTION TO OCCUR.

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ENZYME SHAPE

• SUBSTRATES - THE REACTANTS OF ENZYME CATALYZED
  REACTIONS
• EACH PROTEIN HAS A SPECIFIC SHAPE.
• ACTIVE SITE ON THE PROTEIN HAS A COMPLIMENTARY
  SHAPE TO THE SUBSTRATE.
• ENZYME AND PROTEIN FIT TOGETHER LIKE PUZZLE
  PIECES.
• SEE PG. 52
• ENZYMES ARE REUSABLE.

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ENZYME ACTIVITY

• AFFECTED BY Ph
• Many biological enzymes function best at a pH of
  7
• Most biological enzymes function best at normal
  human body temp.
• Few enzymes function well at high temperature

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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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Regulation of Enzyme Activity

• Because they are catalysts for reactions, enzymes
  can be affected by any variable that influences a
  chemical reaction.
• Many enzymes are affected by temp, pH, etc.

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http//www.youtube.com/watch?vV4OPO6JQLOElistFL
os62yqwp6aQmbJI7D_f7CAindex46featureplpp_video

• Difference between no enzyme and enzyme in
  solution Awesome Animation
• http//www.whfreeman.com/catalog/static/whf/thelif
  ewire6e/con_index.htm?99xex
• How enzymes work in the body!
• http//highered.mcgraw-hill.com/sites/9834092339/s
  tudent_view0/chapter3/enzyme_action_and_the_hydrol
  ysis_of_sucrose.html

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