Cellular Respiration

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Cellular Respiration

• A quick review
• When we eat, we get energy (glucose and other
  sugars)
• Food energy is broken down into usable energy
• Energy used to bond phosphate groups to ADP to
  make ATP
• ADP P ATP

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Cellular Respiration

• What is cell respiration???
• Respiration the process of breaking down food
  molecules and changing these into usable energy -
  ATP
• THE GOAL
• Create ATP for cells to use
• Free up electronshave high energy

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Cellular Respiration
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Cellular Respiration
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Cellular Respiration
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Cellular Respiration

• Types of cell respiration
• Aerobic Processes
• REQUIRE oxygen to take place
• A lot of energy available (efficient)
• Anaerobic Processes
• DO NOT require oxygen to take place
• Get energy quickly (inefficient)

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Cellular Respiration
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Glycolysis

• Involves breaking down 6-carbon sugars
• Break sugars into pyruvic acid molecules
• 3-Carbon molecules
• This process is ANAEROBIC
• No oxygen necessary
• Occurs in the cytoplasm of cells

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Glycolysis
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Glycolysis

• Glycolysis also creates hydrogen ions and free
  electrons
• The whole point of respiration high energy
• H ions bond with NAD to form NADH H
• NADH carries electrons and H ions
• This process uses 4 ADP molecule and creates 4
  ATP molecules

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Glycolysis
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Glycolysis

• TOTAL ATP PRODUCTION
• Glycolysis Step 1 uses 2 ATP molecules
• Glycolysis Step 2 converts 4 ADP molecules into 4
  ATP molecules
• Net ATP production 2 ATP for every
  glucose molecule

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Glycolysis

• When oxygen is present, aerobic respiration
  occurs
• Happens in the mitochondria

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Glycolysis

• Breaking down Pyruvic Acid
• Occurs in the mitochondria
• Pyruvic Acid 3-carbon compound
• Broken down into
• 2-Carbon compoundacetic acid
• Carbon Dioxide

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Glycolysis

• Intermediate Step in Glycolysis
• 2-Carbon CompoundAcetic Acid
• Combined with coenzyme A (CoA)
• Forms compound called acetyl-CoA
• This is only an intermediate stephave to move
  pyruvic acid into Krebs Cycle

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Glycolysis
Glycolysis 2 ATP
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Cellular Respiration
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Citric Acid (Krebs) Cycle

• Produces more ATP and releases more electrons
• Electrons picked up by NAD and FAD
• Organic carrier molecules
• Occurs inside mitochondria
• Mitochondrial Matrix

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Citric Acid (Krebs) Cycle

• Acetyl CoA combines with a 4-carbon molecule to
  form a 6-carbon molecule
• Citric Acid
• Citric Acid broken down into a 5-carbon compound
• NAD removes electrons (NADH H )
• CO2 released

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Citric Acid (Krebs) Cycle

• 5-carbon compound broken down into a 4-carbon
  compound
• ATP created
• NAD removes electrons (NADH H )
• CO2 released
• 4-carbon compound (oxaloacetic acid) is created
• Used to bond with acetyl- CoA to restart cycle

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Citric Acid (Krebs) Cycle
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Citric Acid (Krebs) Cycle
Citric Acid Cycle 2 ATP
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Cellular Respiration
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Electron Transport Chain

• What is the ETC ?
• A series of molecules along which electrons are
  transferred, releasing energy
• Occurs in the mitochondria wall of
  mitochondria
• Aerobic process
• Oxygen is involved
• Acts as the electron acceptor

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Electron Transport Chain

• As the electrons are passed between carrier
  proteins, energy is released
• ATP is created
• Electrons are given up by the carrier molecules
• NADH and FADH2 ------- NAD and FAD

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Electron Transport Chain
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Electron Transport Chain

• As the electrons (H ions) travel down the
  chain, they bond with oxygen
• 2 H 1 O water (H2O)
• Electron acceptor
• Carbon is given off as carbon dioxide

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Electron Transport Chain
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Glycolysis
ETC 34 ATP
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Electron Transport Chain

• A problem exists if there is no oxygen
• Anaerobic process
• When oxygen is used up, electrons cannot be
  removed
• Traffic jam in the mitochondria
• KEY POINT Electron Transport Chain cannot run
  without oxygen

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Anaerobic Respiration

• If no oxygen present after glycolysis, pyruvic
  acid can still be broken down
• Fermentation
• No ATP made during fermentation
• Uses electrons carried by NADH H so that
  NAD can regenerate for glycolysis

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Anaerobic Respiration
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Anaerobic Respiration

• Two types of fermentation
• Lactic Acid Fermentation
• Alcoholic Fermentation

2 Pyruvic Acid
2 Lactic Acid
Glucose
2 Pyruvic Acid
2 Ethanol 2 CO2
Glucose
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Anaerobic Respiration

• Lactic Acid Fermentation
• Muscle fatigue
• When your muscle cells require more energy than
  can be produced
• Lack of oxygen
• Lactic acid build up muscle fatigue
• When oxygen is present, lactic acid breaks down

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Anaerobic Respiration
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Anaerobic Respiration

• Alcohol Fermentation
• Occurs in bacteria, plants and most animals
• Can you think of a bacteria that is used for
  fermentation???
• Pyruvic Acid is converted into ethanol and carbon
  dioxide

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Anaerobic Respiration
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Cellular Respiration
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Cellular Respiration

• General Formula

C6H12O6 6 O2 6 CO2 6 H2O