The Flow of Energy Within Organisms

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The Flow of Energy Within Organisms
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Mighty Mini MotorIn The News
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Energy and Life

• Life involves a constant flow of energy
• Energy ability to do work
• Energy states
• Potential
• Kinetic

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Potential Energy

• Potential Energy
• Energy not actively doing work
• Kinetic
• Energy
• Energy of
• motion

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Energy Laws

• Laws of Thermodynamics
• First law
• Energy can neither be created or destroyed
• Second law
• Disorder in a closed system tend to increase

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Entropy

• Measure of disorder
• Energy is required to overcome entropy
• Organisms have an input of energy to continue to
  function

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Energy and Chemical Reactions

• Chemical reactions release store energy

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Activation Energy

• Required to start reactions
• Helps break or destabilize bonds

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Exergonic Reaction

• Energy is released
• Proceed spontaneously once started
• Catabolic reactions
• Breaks complex molecules to simple
• Releases energy
• Common in organisms

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Endergonic reaction

• Energy used in bonding reactants
• Builds
• molecules
• Called
• anabolic
• reactions

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Metabolic Pathways

• Move, store, release energy
• Keep bodies working

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Enzymes

• Lower activation energy
• Increase rate of reaction (catalyst)

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Substrates

• Substances on which enzymes work
• Bound to active sites by enzymes

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How Enzymes Catalyze an Exergonic Reaction
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Enzyme Substrate
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Enzymes can Catalyze Reactions Between Two
Substrates
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Environmental Conditions Affect Enzyme Activity

• Temperature
• Can change enzyme shape
• Can affect enzyme activity

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Enzymes Work Best in Conditions Specific to an
Organism
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Other Factors Affecting Enzymes

• pH
• Presence of chemicals binding to enzymes
• Activators catalyze reactions
• Inhibitors shuts off enzyme activity

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End Products

• Can regulate enzyme activity

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Cofactors

• Additional parts of enzymes
• Molecules other than proteins
• Help catalyze chemical reactions

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Coenzymes

• Organic cofactor
• Synthesized with vitamins
• Important for many functions

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ATP

• Adenosine triphosphate
• Primary energy carrier of living systems

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ATP

• Unstable covalent bonds on phosphate
• Requires little activation energy
• High energy transfer potential

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Phosphorylation

• Energy transferred along with phosphate
• Used for most cellular work

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ATP ADP Cycle

• ATP loses phosphate group
• Energy is released
• Hydrolysis
• Product is ADP (adenosine diphosphate)
• Phosphate is added to ADP
• Requires energy from exergonic reactions
• Dehydration synthesis
• Product is ATP

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End Chapter 6