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Cellular Respiration: Harvesting Chemical Energy. Respiration is the process of extracting stored energy from glucose to make ATP. Cellular Respiration Equation. C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O and energy
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Respiration is the process of extracting stored energy from glucose to make ATP.
Cellular Respiration Equation C6H12O6 + 6 O2 6 CO2 + 6 H2O and energy As a result of respiration, energy is released from the chemical bonds found in complex organic molecules (food).
Aerobic Respiration • Aerobic Respiration is respiration which takes place in the presence of oxygen
Respiration is controlled by Enzymes …rate is controlled by enzymes
Cell Respiration is divided into 3 stages. (components) 1. Glycolysis 2. Krebs Cycle 3. Oxidative Phosphorylation
Glycolysis • Glyco- glucose, -lysis: to split • Universal step in all forms of respiration • Likely used to supply energy for the ancient cells.
Glycolysis • Function - To split glucose and produce NADH, ATP and Pyruvate (pyruvic acid). • Location - Cytoplasm. • Occurs in 9 steps…. 6 of the steps use magnesium Mg as cofactors.
NAD+ Energy carrier • Nicotinamide Adenine Dinucleotide NAD+ + 2 e- NADH NAD+ = oxidized form NADH = reduced form
Requirements for Glycolysis • Glucose • 2 ATP…. As activation energy • 4 ADP • 2 NAD+ • Enzymes
The Products of Glycolysis • 2 Pyruvic Acids (a 3C acid) • 4 ATP • 2 NADH
Net Energy Result • 2 ATP per glucose • 2 NADH • In summary, glycolysis takes one glucose and turns it into 2 pyruvate, 2 NADH and a net of 2 ATP.
Krebs CycleAlso called: Citric Acid Cycleor Tricarboxylic Acid Cycle • Function: Oxidize pyruvic acid to CO2 • Produce: 3NADH, 1FADH2 and 1ATP • Location: Mitochondria matrix
Formation of Acetyl CoA:Acetyl CoA is formed when the pyruvate , from glycolysis, combines with Coenzyme A… tis takes place in the matrix.
Requirements for Krebs Cycle • Pyruvic acid (3C acid) • Coenzyme A • 3 NAD+ • 1 ADP • 1 FAD • Double this list for each glucose.
Products of Krebs Cycle • 3 CO2 • Acetyl CoA • 3 NADH • 1 ATP • 1 FADH2 • Double this list for each glucose.
Krebs Cycle • Produces most of the cell's energy in the form of NADH and FADH2… not ATP • Does NOT require O2 • The CO2 produced by the Krebs cycle is the CO2 animal exhale when they breathe.
Oxidative Phosphorylation • Process of extracting to energy from NADH and FADH2 to form ATP. • Function: Convert NADH and FADH2 into ATP. • Location: Mitochondria cristae.
Oxidative Phosphorylation • NADH or FADH2 • ADP • O2
Oxidative Phosphorylation • Requires the Electron Transport Chain… the Electron Transport Chain is a collection of proteins, embedded in the inner membrane, used to transport the electrons from NADH and FADH2
Cytochrome c • Cytochrome c: is one of the proteins of the electron transport chain… often used by geneticists to determine relatedness… exists in all living organisms. • The Cytochromes alternate between RED and OX forms and pass electrons down to O2
ATP Yield • Each NADH energizes 3 ATP • Each FADH2 energizes2 ATP
Chemiosmotic Hypothesis • ETC energy is used to move H+ (protons) across the cristae membrane. • ATP is generated as the H+ diffuse back into the matrix through ATP Synthase
ATP Synthase • Uses the flow of H+ to make ATP. • Works like an ion pump in reverse, or like a waterwheel under the flow of H+ “water”.
Alcoholic Fermentation • Carried out by yeast, a kind of fungus.
Alcoholic Fermentation • Uses only Glycolysis. • An incomplete oxidation - energy is still left in the products (alcohol). • Does NOT require O2 • Produces ATP when O2 is not available.
Lactic Acid Fermentation • Uses only Glycolysis. • An incomplete oxidation - energy is still left in the products (lactic acid). • Does NOT require O2 • Produces ATP when O2 is not available.
Lactic Acid Fermentation • Done by human muscle cells under oxygen debt. • Lactic Acid is a toxin and causes soreness and stiffness in muscles.
Fermentation - Summary • Way of using up NADH so Glycolysis can still run. • Provides ATP to a cell even when O2 is absent.
Aerobic vs Anaerobic • Aerobic - Respiration with O2 • Anaerobic - Respiration without O2 • Aerobic - All three Respiration steps. • Anaerobic - Glycolysis only.
Strict vs. Facultative Respiration • Strict - can only carry out Respiration one way… aerobic or anaerobic. • Facultative - can switch respiration types depending on O2 availability. Ex - yeast
ATP yields by Respiration type • Anaerobic - Glycolysis only Gets 2 ATPs per glucose. • Aerobic - Glycolysis, Krebs, and Oxidative Phosphorylation (electron transport chain) Generates many more ATPs per glucose.
Aerobic ATP yield • Glycolysis - 2 ATPS, 2 NADHs • Krebs - 2 ATPS, 8 NADHs, 2 FADH2 • Each NADH = 3 ATP • Each FADH2 = 2 ATP
ATP Sum • 10 NADH x 3 = 30 ATPs • 2 FADH2 x 2 = 4 ATPs • 2 ATPs (Gly) = 2 ATPs • 2 ATPs (Krebs) = 2 ATPs • Max = 38 ATPs per glucose
However... • Some energy is used in shuttling the NADH from Glycolysis into the mitochondria. • Actual ATP yield ~ 36/glucose
Yeast • Would rather do aerobic Respiration; it has 18x more energy per glucose. • But, anaerobic will keep you alive if oxygen is not present.
Importance of Respiration • Alcohol Industry - almost every society has a fermented beverage. • Baking Industry - many breads use yeast to provide bubbles to raise the dough.
Matching Sugar Cane Gin Barley Saki Grapes Tequila Juniper Cones Vodka Agave Leaves Beer Rice Wine Potatoes Rum
Question • Why is the alcohol content of wine always around 12-14%? • Alcohol is toxic and kills the yeast at high concentrations.