Energy and Metabolism Bioenergetics

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Energy and Metabolism(Bioenergetics)

• Lecture 5

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ENERGY

• The capacity to do work
• All life processes require energy.
• Source
• Distribution

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Two Types of Energy

• 1. Potential energy stored energy

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Two Types of Energy

• 2. Kinetic energy energy of motion.actually
  doing something

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• Much of the work of living organisms requires
• potential energy kinetic energy
• Lets talk about the principles of energy.

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Laws of Thermodynamics

• 1st Law
• Energy can neither be created nor destroyed.
• It can only be converted from one form to another
• Waterfall to electricity
• Food to exercise
• Energy transfer is not 100heat loss

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Laws of Thermodynamics

• 2nd Law
• Energy transfer causes things to go from more
  orderly state to a more disorderly state
  (entropy).
• Disorder is more likely than order.

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Source of Energy
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Energy Source

• Source is the sun.
• How do living things capture the suns energy?
• Plants, algae and some bacteria capture the suns
  energy.
• This process is called photosynthesis.

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Energy Flow
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Energy Flow

• SUN PLANTS
• 
  HEAT
• GIRAFFE
• HEAT
• LION

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Plants capture suns energy

• How do we get energy out of plants and animals?
• Input energy (activation energy)
• Yield (output energy)
• If (output) (input) 0
• So.we need to put in less than we get out
• How do we do this?

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Enzymes

• All enzymes are proteins (1 exception).
• They convert substrate product.
• They lower the activation energy.

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Enzymes Are Catalysts

• The process of lowering the activation energy is
  catalysis.
• An example
• CO2 H2O H2CO3
• The enzyme is carbonic anhydrase.
• Without vs with enzyme

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CO2 H2O H2CO3

• Substrate(s)
• Product(s)
• So..how do enzymes do this catalysis?

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How Do Enzymes Work?

• Enzymes are globular proteins.

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• They have active sites where substrates bind to
  the enzyme.
• Enzymes are specific for substrates.

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• 4..Amino acids in active site bind with
  substrate.
• 5. When enzyme binds with substrate, enzyme
  changes shape induced fit.

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• 6. One substrate

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• 7. Two substrates
• CO2 H2O H2CO3
• Enzyme is carbonic anhydrase.
• This enzyme functions to bring the 2 substrates
  close together to allow efficient transfer of
  electrons.

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Factors AffectingEnzyme Activity

• Substrate Product
• Concentration of substrate
• 2. Factors that affect the enzyme (a protein)

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Factors that affectthe enzyme molecule

• Temperature
• pH

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3. Inhibitors

• Inhibitors substance that binds to the enzyme
  to decrease enzyme activity.
• Two types of inhibitors
• Competitive binds to enzyme active site
• Noncompetitive binds elsewhere on enzyme

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4. Cofactors

• Cofactors are located in the active site.
• Manganese zinc are examples
• NAD -- nicotinamide adenine dinucleotide

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Nicotinamide Adenine Dinucleotide
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NAD

• NAD is missing an electron.
• Enzyme binds substrate and NAD.
• Enzyme transfers two electrons from substrate to
  NAD
• NAD NAD (1st electron)
• NAD NADH (2nd electron)
• Now..NADH has a greater amount of energy
  (2e-).which it can pass on.

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ATPThe energy currency of life

• Adenosine triphosphate
• Energy carrying/transferring molecule w/in the
  cell

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Structure of ATP
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Composition of ATP

• Consists of three components
• 5-carbon sugar ribose

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Composition of ATP

• 5 carbon sugar ribose
• Adenine (a purine)

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Composition of ATP

• 5-carbon sugar ribose
• Adenine
• Triphosphate P P P

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• It is the bonds between the phosphates that
  possess large amount of energy.
• When a cell needs energy for some process.
• ATP ADP Pi ENERGY
• P P P P P P ENERGY
• The activation energy of catalysis of ATP to ADP
  is relatively small.
• ATP is the universal energy donor.