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

1. Source is the sun.
2. How do living things capture the suns energy?
3. Plants, algae and some bacteria capture the suns
   energy.
4. 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

1. How do we get energy out of plants and animals?
2. Input energy (activation energy)
3. Yield (output energy)
4. If (output) (input) 0
5. So.we need to put in less than we get out
6. 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?

1. Enzymes are globular proteins.

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1. They have active sites where substrates bind to
   the enzyme.
2. 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

1. Temperature
2. 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

1. NAD is missing an electron.
2. Enzyme binds substrate and NAD.
3. Enzyme transfers two electrons from substrate to
   NAD
4. NAD NAD (1st electron)
5. NAD NADH (2nd electron)
6. 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

1. 5 carbon sugar ribose
2. Adenine (a purine)

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Composition of ATP

1. 5-carbon sugar ribose
2. Adenine
3. 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.