Pre

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Pre AP 10/11

• Warm UP
• Notes Enzymes and Bioenergetics (CH 2 section 4)
• HW Print Enzyme Lab (posted today)
• Study for Quiz FRIDAY.
• Check your assignment for PSAT

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Warm - UP

• What are enzymes and what do they do?

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Enzymes
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What Are Enzymes?

• Most enzymes are Proteins (tertiary and
  quaternary structures)
• Act as Catalyst to accelerates a reaction
• Not permanently changed in the process

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Enzymes

• Are specific for what they will catalyze
• Are Reusable
• End in ase
• -Sucrase
• -Lactase
• -Maltase

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How do enzymes Work?

• Enzymes work by weakening bonds which lowers
  activation energy

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Enzymes
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Enzyme-Substrate Complex

• The substance (reactant) an enzyme acts on is the
  substrate

Joins
Substrate
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Active Site

• A restricted region of an enzyme molecule which
  binds to the substrate.

Substrate
Active Site
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Induced Fit

• A change in the shape of an enzymes active site
• Induced by the substrate
• Different from lock and key analogy

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Factors Affecting Enzyme Activity

• Temperature
• pH
• Cofactors Coenzymes
• Inhibitors

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Temperature pH

• Most enzymes like near neutral pH (6 to 8)
• Denatured (unfolded) by ionic salts
• High temperatures are the most dangerous
  reactions denature enzymes (Most like normal
  Body temperatures)

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Cofactors and Coenzymes

• Cofactors Inorganic substances (zinc, iron) and
• Coenzymes vitamins (organic) are sometimes need
  for proper enzymatic activity.
• Example
• Iron must be present in the quaternary
  structure of hemoglobin in order for it to pick
  up oxygen.

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Two examples of Enzyme Inhibitors

• a. Competitive inhibitors are chemicals that
  resemble an enzymes normal substrate and compete
  with it for the active site.

Substrate
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Inhibitors

• b. Noncompetitive inhibitors
• Inhibitors that do not enter the active site,
  but bind to another part of the enzyme causing
  the enzyme to change its shape, which in turn
  alters the active site.

Substrate
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BIOENERGETICS
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What is Bioenergetics?

• The study of energy in living systems
  (environments) and the organisms (plants and
  animals) that utilize them

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Energy

• Required by all organisms
• May be Kinetic or Potential energy

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Kinetic Energy

• Energy of Motion
• Heat and light energy are examples

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Kinetic Energy
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Potential Energy

• Energy of position
• Includes energy stored in chemical bonds
  chemical gradients

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Two Types of Energy Reactions
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Endergonic Reactions

• Chemical reaction that requires a net input of
  energy. (energy absorbing)
• Photosynthesis
• 6CO2 6H2O ? C6H12O6 6O2

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Exergonic Reactions

• Chemical reactions that releases energy (energy
  releasing)
• Cellular Respiration
• C6H12O6 6O2 ? 6CO2 6H2O

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Metabolic Reactions of Cells
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What is Metabolism?

• The sum total of the chemical activities of all
  cells.

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Two Types of Metabolism

• Anabolic Pathways
• Catabolic Pathways

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Anabolic Pathway

• Metabolic reactions, which consume energy
  (endergonic), to build complicated molecules from
  simpler compounds.
• Photosynthesis
• 6CO2 6H2O ? C6H12O6 6O2

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Catabolic Pathway

• Metabolic reactions which release energy
  (exergonic) by breaking down complex molecules in
  simpler compounds
• Cellular Respiration
• C6H12O6 6O2 ? 6CO2 6H2O

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Cellular Energy - ATP
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ATP

• Components
• 1. adenine nitrogenous base
• 2. ribose five carbon sugar
• 3.phosphate group chain of 3

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Adenosine Triphosphate

• Three phosphate groups-(two with high energy
  bonds
• Last phosphate group (PO4) contains the MOST
  energy

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Breaking the Bonds of ATP

• Process is called phosphorylation
• Occurs continually in cells
• Enzyme ATP-ase can weaken break last PO4 bond
  releasing energy free PO4

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How does ATP work ?

• Organisms use enzymes to break down energy-rich
  glucose to release its potential energy
• This energy is trapped and stored in the form of
  adenosine triphosphate(ATP)

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How Much ATP Do Cells Use?

• It is estimated that each cell will generate and
  consume approximately 10,000,000 molecules of ATP
  per second

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Coupled Reaction - ATP

• The exergonic hydrolysis of ATP is coupled with
  the endergonic dehydration process by
  transferring a phosphate group to another
  molecule.

ATP
H2O
ADP P
H2O
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Hydrolysis of ATP

• ATP H2O ? ADP P (exergonic)

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Hyrolysis is Exergonic
Energy Used by Cells
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Dehydration of ATP

• ADP P ? ATP H2O (endergonic)

Dehydration(Remove H2O
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Dehydration is Endergonic
Energy is restored in Chemical Bonds
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Review
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How many high energy phosphate bonds does ATP
have?
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Which is true of photosyntheis?
Anabolic or Catabolic
Exergonic Or Endergonic
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The breakdown of ATP is due to
Dehydration or Hydrolysis
H2O added or H2O removed
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Which Reactions are often Coupled in Organisms
BOTH
Hydrolysis or Dehydration
BOTH
Anabolism or Catabolism
BOTH
Endergonic or Exergonic