Glycolysis & Fermentation

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Glycolysis Fermentation

• 7.1

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ATP is the main energy currency of cells

• Cellular respiration process of making ATP by
  breaking down organic compounds
• A catabolic, exergonic, oxygen (O2) requiring
  process that uses energy extracted from
  macromolecules (glucose) to produce energy (ATP)
  and water (H2O).

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Cellular respiration equation

• C6H12O6 6O2 ? 6CO2 6H2O energy

byproduct
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• Who uses cellular respiration and
• Where does it take place?

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Who undergoes cellular respiration? (eukaryotes)

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

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What are the Stages of Cellular Respiration?

• Glycolysis
• The Krebs Cycle
• The Electron Transport Chain

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Where? 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.

byproduct
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Breakdown of Cellular Respiration

• 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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GLYCOLYSIS

• biochemical pathway, yields 2 ATP
• Occurs in cytosol
• Converts NAD oxidized to NADH to produce pyruvic
  acid then reduced to form lactic acid
• With Oxygen gt aerobic - additional ATP
• Without Oxygen gt anaerobic - fermentation yields
  NO additional ATP

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1. Glycolysis

• A. Energy use 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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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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Animation

• http//www.science.smith.edu/departments/Biology/B
  io231/glycolysis.html

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RECALL

• Redox one reactant is oxidized while another is
  reduced
• oxidized loses e- and becomes pos
• reduced gains e- and becomes neg

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GYLCOLYSIS RECAP

• glucose oxidized yields pyruvic acid
• reactions take place in cytosol
• NAD to NADH (electron acceptor)
• Pyruvic acid yields 4 ATP but 2 used in process
  (so net yield is 2 ATP)

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Fermentation

• fermentation is the formation of alcohol from
  sugar.
• Occurs in cytosol when NO Oxygen is present
  (called anaerobic).
• Remember glycolysis is part of fermentation.
• Two Types
• 1. Lactic Acid (animal cells)
• 2. Alcohol (plant cells)

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Lactic acid fermentation

• NADH oxidized to NAD
• e.g. Yogurt, cheese
• in muscle not enough oxygen so switch to
  anaerobic respiration b/c oxygen is depleted
  which makes cytosol acidic so produces cramps

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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 (phosphorylation)
• 2 - Lactic Acids

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Alcoholic Fermentation

• convert pyruvic to ethyl alcohol by removing CO2
• e.g. bread, beer, wine - need enzymes in yeast

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Alcohol Fermentation

• Plants and Fungi ? beer and wine

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Alcohol Fermentation

• End Products
• 2 - ATP (phosphorylation)
• 2 - CO2
• 2 - Ethanols

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• glycolysis is not efficient but unicellular
  organisms dont need much energy to function
• E.g. paramecium, ameoba
• probably evolved early in history of life

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• kilocalories 1 kcal 1000 cal

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How does the overall equation for aerobic
respiration relate to its four stages?

• http//w3.dwm.ks.edu.tw/bio/activelearner/07/ch7in
  tro.html

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Aerobic Respiration

• 7.2

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Aerobic respiration

• cellular respiration that requires oxygen
• 2 major stages Krebs cycle electron transport
  chain

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STAGE 1

• Krebs cycle biochemical pathway that breaks
  down acetyl CoA producing CO2, Hydrogen, ATP
• Aka Citric Acid Cycle
• Completes oxidation of glucose began in
  glycolysis
• Takes place in/ mitochondrion unlike glycolysis
  that occurs in/ cytosol

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• Pyruvic acid from glycolysis diffuses across
  membrane to Mitochondrial matrix forms Acetyl
  coenzyme A (acetyl CoA)

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5 Steps in Krebs cycle

• Step 1 produces citric acid
• Step 2 releases CO2
• Step 3 releases CO2
• Step 4 conversion of 4-carbon compound
• Step 5 4-carbon compound converted back to
  oxaloacetic acid

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• Citric acid - formed when acetyl CoA combines
  with Oxaloacetic acid
• FAD - flavin adenine dinucleotide like NAD b/c
  accepts electrons

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• Each turn of citric acid cycle produces
• ATP, NADH, FADH2

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• In glycolysis 1 glucose produced 2 ATP which is
  same as Krebs cycle

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Stage 2

• Electron transport chain occurs along inner
  membrane
• Concentration gradient between 2 membranes drive
  chain
• ATP synthase catalyzes ATP from ADP and phosphate
  ion known as chemiosmosis just like photosynthesis

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Efficiency of energy

• glycolysis 2 ATP
• Krebs 2 ATP
• E.T.C. 34 ATP
• 38 ATP
• but some is used to pump NADH across membrane so
  36 ATP

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summary of Cellular Respiration
http//www.estrellamountain.edu/faculty/farabee/bi
obk/BioBookGlyc.html
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References

• http//www.search.com/reference/Mitochondrion
• http//images.google.com/imgres?imgurlhttp//micr
  obewiki.kenyon.edu/images/thumb/2/25/Mitochondria.
  gif/400px-Mitochondria.gifimgrefurlhttp//microb
  ewiki.kenyon.edu/index.php/Mitochondriah311w40
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  tbnh96tbnw124prev/images3Fq3Dmitochondrial
  2Bmatrix26start3D10026ndsp3D2026svnum3D102
  6um3D126hl3Den26rlz3D1T4GGIC_enUS233US23326s
  a3DN
• http//images.google.com/imgres?imgurlhttp//wps.
  prenhall.com/wps/media/objects/486/498525/FG06_12F
  R.JPGimgrefurlhttp//wps.prenhall.com/esm_freema
  n_biosci_1/0,6452,498573-,00.htmlh268w550sz4
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  5tbnw133prev/images3Fq3Dmitochondrial2Bmatr
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  _enUS233US23326sa3DG
• http//www.estrellamountain.edu/faculty/farabee/bi
  obk/BioBookGlyc.html
• www.biologyjunction.com