AIM: How do enzymes aid chemical reactions?

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AIM How do enzymes aid chemical reactions?

• DO NOW What happens during a chemical reaction?
  Consider the reaction AB CD --gt AC BD. What
  are the reactants? The products?
• VOCABULARY chemical reaction, enzyme, activation
  energy, catalyst, substrate, induced
• Go over HW pg 43 questions 1, 2, 4
• Science Fair topic due Monday via email
• Pg 53 questions 1-5 due Tuesday
• Test Wednesday Chapter 2 Sections 1, 2, AND 4
  ONLY!

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Homework Review

• Use the structure of a water molecule to explain
  why it is polar.
• The oxygen molecule has a greater attraction for
  the electrons. Therefore, the oxygen end of the
  molecule is slightly negative, while the hydrogen
  ends are slightly positive.
• Compare acidic and basic solutions.
• Acidic solutions contain more H ions than OH-
  ions. Basic solutions contain more OH- than H.
  Acids taste sour, while bases taste bitter.
• What does pH measure?
• pH measures the concentration of H in a
  solution.

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Review of Do Now

• What happens during a chemical reaction?
• Bonds are broken and re-formed.
• Consider the reaction AB CD --gt AC BD
• What are the reactants? The products?
• Reactants AB, CD
• Products AC, BD

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Collision Theory Mrs. DAnna vs. Mike Tyson for
the (sort of) heavyweight championship of the
world!

• In order for a chemical reaction to take place,
  the reactants must collide with sufficient energy
  and in the proper orientation.
• The initial energy required to get a chemical
  reaction started is called the activation energy.

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What energy changes take place during a chemical
reaction?
What do you think is represented by the following
labeled parts of the graph Reactants Products EA
delta G
Is this reaction endothermic or
exothermic? Explain.
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Closing QuestionSketch an energy diagram for
the reverse chemical reaction.Should this
reaction be exothermic or endothermic?
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Is this reaction endothermic or exothermic? How
do you know?
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Summary

• Chemical reactions occur when bonds between
  molecules are broken and reformed.
• An exothermic reaction releases energy (heat)
• An endothermic reaction absorbs energy (heat)

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What are some factors that effect enzyme
activity?

• Do Now What takes place in a chemical reaction?
  What is the difference between exothermic and
  endothermic?
• VOCABULARY chemical reaction, enzyme, activation
  energy, catalyst, substrate, induced
• Science Fair topic due Monday via email
• Pg 53 questions 1-5 due Tuesday
• Test Wednesday Chapter 2 sections 1, 2, 4 ONLY!

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What do you already know about enzymes? (2 min)

• What type of molecule is an enzyme?
• What do enzymes do?
• How do they work?

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Characteristics of Enzymes

• Proteins
• Substrate
• Specific (lock and key)
• Induced fit (handshake)
• Biological catalysts
• Not consumed by a reaction

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Induced Fit with Substrate
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An Induced Fit
A
B
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How do enzymes act as biological catalysts?
How is the red curve (enzyme added) different
from the black curve (no enzyme added)?
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Activity

• Page 51
• Analyzing Data
• Read the passage and study the graph.
• Answer questions 1-6 in groups.

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Closing Thought

• What is the effect of pH on enzyme activity?
• Why do you think this occurs?

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Effect of Temperature and pH on Enzyme Activity