Cellular Respiration

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Cellular Respiration
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Cellular Respiration

• A catabolic, exergonic, oxygen (O2) requiring
  process that uses energy extracted from
  macromolecules (glucose) to produce energy (ATP)
  and water (H2O).
• C6H12O6 6O2 ? 6CO2 6H2O energy

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Question

• In what kinds of organisms does cellular
  respiration take place?

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Plants, Animals, Protists, Bacteria, and Fungi!!

• Ex Plants - Autotrophs self-producers.
• Ex Animals - Heterotrophs consumers.

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Mitochondria

• Organelle where cellular respiration takes place.

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Redox Reaction

• Transfer of one or more electrons from one
  reactant to another.
• Two types
• 1. Oxidation
• 2. Reduction

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Oxidation Reaction

• The loss of electrons from a substance.
• Or the gain of oxygen.
• C6H12O6 6O2 ? 6CO2 6H2O energy

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Reduction Reaction

• The gain of electrons to a substance.
• Or the loss of oxygen.

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Breakdown of Cellular Respiration

• Four main parts (reactions).
• 1. Glycolysis (splitting of sugar)
• a. cytosol, just outside of mitochondria.
• 2. Grooming Phase
• a. migration from cytosol to matrix.

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Breakdown of Cellular Respiration

• 3. Krebs Cycle (Citric Acid Cycle)
• a. mitochondrial matrix
• 4. Electron Transport Chain (ETC) and
• Oxidative Phosphorylation
• a. Also called Chemiosmosis
• b. inner mitochondrial membrane.

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An Overview of Cellular Respiration
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1. Glycolysis

• Occurs in the cytosol just outside of
  mitochondria.
• Two phases (10 steps)
• A. Energy investment phase
• a. Preparatory phase (first 5 steps).
• B. Energy yielding phase
• a. Energy payoff phase (second 5 steps).

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1. Glycolysis

• A. Energy Investment Phase

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1. Glycolysis

• B. Energy Yielding Phase

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1. Glycolysis

• Total Net Yield
• 2 - 3C-Pyruvate (PYR)
• 2 - ATP (Substrate-level Phosphorylation)
• 2 - NADH

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The Energy Input and Output of Glycolysis
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Substrate-Level Phosphorylation

• ATP is formed when an enzyme transfers a
  phosphate group from a substrate to ADP.

Example PEP to PYR
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Fermentation

• Occurs in cytosol when NO Oxygen is present
  (called anaerobic).
• Remember glycolysis is part of fermentation.
• Two Types
• 1. Alcohol Fermentation
• 2. Lactic Acid Fermentation

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Alcoholic Fermentation

• Plants and Fungi?beer and wine

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Alcoholic Fermentation

• 2 Pyruvates 2NADH 2ATP ?
• 2 Ethanols 2 CO2 2 NAD

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Lactic Acid Fermentation

• Animals (pain in muscle after a workout)

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Lactic Acid Fermentation

• End Products Lactic acid fermentation
• 2 - ATP (substrate-level phosphorylation)
• 2 - Lactic Acids
• 2 NAD

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2. Grooming Phase

• Occurs when Oxygen is present (aerobic).
• 2 Pyruvate (3C) molecules are transported through
  the mitochondria membrane to the matrix and is
  converted to 2 Acetyl CoA (2C) molecules.

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2. Grooming Phase

• End Products grooming phase
• 2 - NADH
• 2 - CO2
• 2- Acetyl CoA (2C)

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3. Krebs Cycle (Citric Acid Cycle)

• Location mitochondrial matrix.
• Acetyl CoA (2C) bonds to Oxalacetic acid (4C -
  OAA) to make Citrate (6C).
• It takes 2 turns of the Krebs Cycle to oxidize 1
  glucose molecule.

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3. Krebs Cycle (Citric Acid Cycle)
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3. Krebs Cycle (Citric Acid Cycle)
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3. Krebs Cycle (Citric Acid Cycle)

• Total net yield (2 turns of Krebs Cycle)
• 1. 2 - ATP (substrate-level phosphorylation)
• 2. 6 - NADH
• 3. 2 - FADH2
• 4. 4 - CO2

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4. Electron Transport Chain (ETC) and Oxidative
Phosphorylation (Chemiosmosis)

• Location inner mitochondrial membrane.
• Uses ETC (cytochrome proteins) and ATP Synthase
  (enzyme) to make ATP.
• ETC pumps H (protons) across innermembrane
  (lowers pH in innermembrane space).

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4. Electron Transport Chain (ETC) and Oxidative
Phosphorylation (Chemiosmosis)

• The H then move via diffusion (Proton Motive
  Force) through ATP Synthase to make ATP.
• All NADH and FADH2 converted to ATP during this
  stage of cellular respiration.
• Each NADH converts to 3 ATP.
• Each FADH2 converts to 2 ATP (enters the ETC at a
  lower level than NADH).

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4. Electron Transport Chain (ETC) and Oxidative
Phosphorylation (Chemiosmosis)

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Chemiosmosis Couples the Electron Transport Chain
to ATP Synthesis
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• Chemiosmosis and the electron transport chain

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4. ETC and Oxidative Phosphorylation
(Chemiosmosis for NADH)
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4. ETC and Oxidative Phosphorylation
(Chemiosmosis for FADH2)
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TOTAL ATP YIELD

• 1. 04 ATP - substrate-level phosphorylation
• 2. 34 ATP - ETC oxidative phosphorylation
• 18 ATP - converted from 6 NADH - Krebs
  Cycle
• 38 ATP - TOTAL YIELD

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Eukaryotes (Have Membranes)

• 02 ATP - glycolysis (substrate-level
  phosphorylation)
• 04 ATP - converted from 2 NADH - glycolysis
• 06 ATP - converted from 2 NADH - grooming phase
• 02 ATP - Krebs cycle (substrate-level
  phosphorylation)
• 18 ATP - converted from 6 NADH - Krebs cycle
• 04 ATP - converted from 2 FADH2 Krebs cycle
• 36 ATP - TOTAL

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Maximum ATP Yield for Cellular Respiration
(Eukaryotes)
36 ATP (maximum per glucose)
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Prokaryotes (Lack Membranes)

• Total ATP Yield
• 02 ATP - glycolysis (substrate-level
  phosphorylation)
• 06 ATP - converted from 2 NADH - glycolysis
• 06 ATP - converted from 2 NADH - grooming phase
• ATP - Krebs cycle (substrate-level
  phosphorylation)
• 18 ATP - converted from 6 NADH - Krebs cycle
• 04 ATP - converted from 2 FADH2 - Krebs cycle
• 38 ATP - TOTAL

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Question

• In addition to glucose, what other various food
  molecules are use in Cellular Respiration?

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Catabolism of VariousFood Molecules

• Other organic molecules used for fuel.
• 1. Carbohydrates polysaccharides
• 2. Fats glycerol and fatty acids
• 3. Proteins amino acids