requiring energy Cellular Respiration - Mrs. Kohout's ... Cellular Respiration 2 Cellular Respiration

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  • 12/6/2012

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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).

     Equation for CR?

    C6H12O6 + 6O2  6CO2 + 6H2O + energy

    glucose ATP

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    Question:

     In what kinds organisms does cellular respiration take place?

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    Plants and Animals

     Plants

     Autotrophs: self-producers.

     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.  (think backwards)

     Or the gain of oxygen.

    C6H12O6 + 6O2 6CO2 + 6H2O + energy

    glucose ATP

    Oxidation

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    Reduction Reaction

     The gain of electrons to a substance.

     Or the loss of oxygen.

    glucose ATP

    C6H12O6 + 6O2  6CO2 + 6H2O + energy

    Reduction

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    Breakdown of Cellular Respiration

     Four main parts (reactions).

    1. Glycolysis (splitting of sugar)  Glyco = sugar

     Lysis = split

     cytoplasm, just outside of mitochondria.

     Glucose  2 molecules pyruvic acid

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    Just so we’re on the same page…

     What is NADH?

     NAD is an electron carrier much like NADP+ (photosynthesis) Glycolysis gives off 4 electrons.

    2NAD’s pick up the 4 e- (2 each) and become NADH.

    NADH holds the electrons until they can be transferred to other molecules

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    Breakdown of Cellular Respiration

    2. Grooming Phase  migration from cytosol to matrix.

    3. Krebs Cycle (Citric Acid Cycle)

     mitochondrial matrix

    4. Electron Transport Chain (ETC) and Oxidative Phosphorylation a. Also called Chemiosmosis b. inner mitochondrial membrane.

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    The breakdown

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    1. Glycolysis

     Occurs in the cytosol just outside of mitochondria.

     Two phases

    A. Energy investment phase

    a. Preparatory phase (first steps). B. Energy yielding phase

    a. Energy payoff phase (second steps).

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     Glycolysis is an energy releasing reaction. Is energy necessary for glycolysis to start? Why? Need ATP to get things going.

    Analogy –earn interest, must put in $ first

     4 ATP are released in glycolysis for a net gain of 2 ATP – (“interest” is earned right away)

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    1. Glycolysis

     Total Net Yield

    2 - 3C-Pyruvate (PYR)

    2 - ATP (Substrate-level Phosphorylation)

    2 - NADH

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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.

    Mitochondrial

    Matrix

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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)

     Location: inner mitochondrial membrane.

     Uses ETC (proteins) and ATP Synthase (enzyme) to make ATP.

     ETC pumps H+ (protons) across inner membrane (lowers pH in inner membrane space).

    Inner

    Mitochondrial

    Membrane

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    4. Electron Transport Chain (ETC)

     The H+ then move via diffusion 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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    That’s all for now….

    Until we draw the cycles!!!

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    1. Glycolysis

    A. Energy Investment Phase:

    Glucose (6C)

    Glyceraldehyde phosphate (2 - 3C)

    (G3P or GAP)

    2 ATP - used

    0 ATP - produced

    0 NADH - produced

    2ATP

    2ADP + P

    C-C-C-C-C-C

    C-C-C C-C-C

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    1. Glycolysis

    B. Energy Yielding Phase

    Glyceraldehyde phosphate (2 - 3C) (G3P or GAP)

    Pyruvate (2 - 3C)

    (PYR)

    0 ATP - used

    4 ATP - produced

    2 NADH - produced 4ATP

    4ADP + P

    C-C-C C-C-C

    C-C-C C-C-C

    GAP GAP

    (PYR) (PYR)

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    Substrate-Level Phosphorylation

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

    Substrate

    O-

    C=O

    C-O-

    CH2 P P P

    Adenosine

    ADP (PEP)

    Example:

    PEP to PYR

    P P P

    ATP

    O-

    C=O

    C=O

    CH2

    Product

    (Pyruvate)

    Adenosine

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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)

    Krebs

    Cycle

    1 Acetyl CoA (2C)

    3 NAD+

    3 NADH

    FAD

    FADH2

    ATP ADP + P

    (one turn)

    OAA (4C) Citrate (6C)

    2 CO2

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    3. Krebs Cycle (Citric Acid Cycle)

    Krebs

    Cycle

    2 Acetyl CoA (2C)

    6 NAD+

    6 NADH

    2 FAD

    2 FADH2

    2 ATP 2 ADP + P

    (two turns)

    OAA (4C) Citrate (6C)

    4 CO2

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

    Inner

    membrane

    Outer

    membrane

    Inner

    membrane space Matrix

    Cristae

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    4. ETC and Oxidative Phosphorylation (Chemiosmosis for NADH)

    NADH

    + H+

    ATP

    Synthas

    e

    1H+ 2H+ 3H+

    higher H+

    concentration

    H+

    ADP + ATP

    lower H+

    concentration

    H+

    (Proton Pumping)

    P

    E T C

    NAD+

    2H+ + 1/2O2 H2O

    Intermembrane Space

    Matrix

    Inner

    Mitochondrial

    Membrane

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    4. ETC and Oxidative Phosphorylation (Chemiosmosis for FADH2)

    FADH2 + H+

    ATP

    Synthas

    e

    1H+ 2H+

    higher H+

    concentration

    H+

    ADP + ATP

    lower H+

    concentration

    H+

    (Proton Pumping)

    P

    E T C

    FAD+ 2H+ +

    1/2O2 H2O

    Intermembrane Space

    Matrix

    Inner

    Mitochondrial

    Membrane

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    TOTAL ATP YIELD

    1. 04 ATP - substrate-level phosphorylation

    2. 34 ATP - ETC & oxidative phosphorylation

    38 ATP - TOTAL YIELD

    ATP 32

    Eukaryotes (Have Membranes)

     Total ATP Yield

    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)

    Glucose

    Glycolysis

    2ATP 4ATP 6ATP 18ATP 4ATP 2ATP

    2 ATP (substrate-level phosphorylation)

    2NADH

    2NADH

    6NADH

    Krebs

    Cycle

    2FADH2

    2 ATP (substrate-level phosphorylation)

    2 Pyruvate

    2 Acetyl CoA

    ETC and Oxidative

    Phosphorylation

    Cytosol

    Mitochondria

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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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    Alcohol Fermentation

     Plants and Fungi  beer and wine

    glucose

    Glycolysis

    C

    C

    C

    C

    C

    C

    C

    C

    C 2 Pyruvic

    acid

    2ATP 2ADP

    + 2

    2NADH

    P

    2 NAD+

    C

    C

    2 Ethanol 2CO2

    released

    2NADH 2 NAD+

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    Alcohol Fermentation

     End Products: Alcohol fermentation

    2 - ATP (substrate-level phosphorylation)

    2 - CO2

    2 - Ethanol’s

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