Chapter 7 Lecture Presentation Part 1 PDF

Today in BIO 119 § Lecture: Chapter 7 § Lab: Exercise #8 § Lab #7 due § Tomorrow: Exam 2 Chapter 7  Part 1 Key Questions 1. What is the role of ATP in the cell? 2. Define the terms: phosphorylation, dephosphorylation, oxidation, reduction, chemiosmosi...

Today in BIO 119 § Lecture: Chapter 7 § Lab: Exercise #8 § Lab #7 due § Tomorrow: Exam 2 Chapter 7  Part 1 Key Questions 1. What is the role of ATP in the cell? 2. Define the terms: phosphorylation, dephosphorylation, oxidation, reduction, chemiosmosis, fermentation, photosynthesis, cellular respiration, glycogenesis, glycogenolysis, gluconeogenesis, lipogenesis, and lipolysis. 3. List the reactants and products for glycolysis, the transition reaction, the citric acid cycle/Krebs cycle, and oxidative phosphorylation. 4. Compare and contrast the processes of glycolysis, transition reaction, the citric acid cycle/Krebs cycle, and oxidative phosphorylation. 5. Compare and contrast substrate level phosphorylation and oxidative phosphorylation. 6. What are the coenzymes that are critical for the redox reactions of aerobic cellular respiration? Specify the processes of reduction and oxidation and the movement of H ions associated with each. 7. Describe the process of lactic acid and alcoholic fermentation, identify organisms that undergo each and how these organisms benefit from each type of fermentation.  7.1 Energy & Cells All living organisms require energy to sustain life Biochemical Reactions (metabolic reactions): Chemical reactions requiring enzymes at each step  Photosynthesis & Cellular Respiration Photosynthesis Reactants: CO2 + H2O Products: O2 + carbohydrates (but can be proteins and/or lipids) Cellular Respiration Reactants: O2 + organic molecules Products: CO2 + H2O + ATP 7.2 Generating ATP  Generating ATP Phosphorylation: addition of phosphate to any molecule Addition of phosphate group requires energy (endergonic) Reduction Reaction Anabolic  Generating ATP § ATP loses a phosphate group (dephosphorylation) energy is released and can be transferred to another molecule or released as heat. § Oxidation/Catabolic Reaction  Generating ATP Two Mechanisms to form ATP 1.) Substrate-level Phosphorylation: uses enzyme/substrate occurs during glycolysis & Citric Acid (Krebs) cycle ADP + P → ATP  Generating ATP 2.) Oxidative Phosphorylation (OXPHOS) The generation of ATP within the mitochondria in a reaction sequence that requires coenzymes, electrons (H), and the presence of oxygen  Generating ATP Oxidative Phosphorylation Electron Transport Chain (ETC) Electrons are shuttled and release energy used to pump H+. This creates a positive charge on one side of the inner membrane (of the mitochondria) & negative charge on the other  Generating ATP Oxidative Phosphorylation Chemiosmosis At certain protein channels, H+ allowed back across membrane which creates energy to make ATP  Generating ATP Oxidative Phosphorylation Total ATP production related to the number of H+ ions used We eat to get H + to run OXPHOS  Oxidation – Reduction Reactions Involve Oxidation – Reduction Reactions Oxidation (loss of electrons from it’s H) Glucose is oxidized (H loses it’s e-) Reduction (gain of electrons with H) Electron recipient is reduced O2 is reduced – it gains electrons (H) to form water Oxidation – Reduction Reactions  Oxidation – Reduction Reactions § Coenzyme FAD (derivative of Vitamin B2) § Accepts two hydrogen atoms from TCA cycle § Gains two electrons to form FADH2 § Coenzyme NAD (derivative of Vitamin B3) § Accepts two hydrogen atoms § Gains two electrons (releases other H) to form NADH Oxidation – Reduction Reactions  Forming ATP Oxidative Phosphorylation § Allows slow, gradual release of ATP to prevent cell from blowing up! Uses energy from electrons (ElectronTransportChain) To form a proton (H+)  Reactive Oxygen Species High energy electrons are dangerous Electrons form superoxides and hydrogen peroxide Contribute to aging, disease, cancer Antioxidants bind these electrons to decrease these effects. Cells use oxygen go bind to electrons to form O2- ion which combines with 2 H+ to form H2O 7.4 An Overview of Aerobic Cellular Respiration What do I need to know about each step of aerobic cellular respiration? § Where is it taking place? § What are the reactants? § What are the products? § How is the ATP made?  Cellular Respiration Equation § C6H12O6 + 6O2  6CO2 + 6H2O + ATP § 1 Glucose +6 oxygen molecules yields 6 carbon dioxides molecules + 6 water molecules + energy 7.4 An Overview of Aerobic Cellular Respiration 7.4 An Overview of Aerobic Cellular Respiration Overview of Glycolysis and the Transition Step 7.4 An Overview of Aerobic Cellular Respiration Overview of the Citric Acid Cycle & OXPHOS 7.5 The Details of Aerobic Cellular Respiration  Glycolysis First pathway Occurs in cytoplasm Does not require oxygen Uses glucose to produce ATP Glucose → 2 ATP (net), 2 NADH, 2 pyruvate  Glycolysis 1. glucose enters cell via facilitated diffusion (also needs insulin) and is phosphorylated to glucose-6- phosphate P- C6H12O6 § enzymes: skeletal muscle liver § uses 1 ATP *important for 2 reasons: 1.) traps glucose within cell 2.) “primes” reaction for further processing  Glycolysis 2. glucose 6-PO4 flips and is now called fructose 6-phosphate : C6H12O6-P 3. fructose-6-PO4 is phosphorylated into fructose 1,6,diphosphate: P-C6H12O6-P enzyme: PFK uses 1 ATP  Glycolysis 4. fructose 1,6,diphosphate splits in half forming 2 molecules of glyceraldehyde-3-PO4 P-C3H6O36 P-C3H6O3-P  Glycolysis 5. NAD donates phosphate which attaches to each glyceraldehyde-3-PO4 P-C3H6O3-P P -C3H6O3-P 6. each glyceraldehyde-3-PO4 is oxidized by the removal of 2H NAD + 2H - 2 NADH P-C3H4O3-P P -C3H4O3-P  Glycolysis 7-10. each P-C3H4O3-P molecule is stripped of its PO4 forming 4 ATP molecules ADP + P ATP C3H4O3 is pyruvic acid Glycolysis  Glycolysis Glycolysis: Final Products: 2 molecules of pyruvic acid 2 molecules of NADH (go to mitochondria for OXPHOS) 4 molecules of ATP = Net Gain of 2 Via substrate level phosphorylation Glycolysis  Glycolysis Pyruvic Acid: With O2: continues on to Citric Acid or Krebs Cycle Without O2 – NADH cannot unload H+ ions at ETC so “dumps” them onto pyruvic acid to form lactic acid or ethyl alcohol C3H4O3 + 2H → C3H6O3 is lactic acid  Cell membrane H2O SP  Transition Step (Reaction) Citric Acid Cycle begins with acetyl CoA Pyruvic acid/pyruvate (from glycolysis) is converted into acetyl CoA 1. Removal of C & 2 O → CO2 2. Removal of H→ NADH 3. Acetic acid + coenzyme A = acetyl CoA Transition reaction H2O CO2  Citric Acid (Krebs) Cycle (CAC) Occurs in the matrix of mitochondria Begins with formation of citric acid from acetyl CoA (derived from pantothenic acid)  Citric Acid (Krebs) Cycle Step one: acetyl CoA + oxaloacetic acid citric acid (citrate)  Citric Acid (Krebs) Cycle citric acid continues through the steps of the Krebs cycle at certain steps carbons are removed forming CO2 TCA animation  Citric Acid (Krebs) Cycle one ATP molecule is formed via substrate level phosphorylation Each turn of the Krebs cycle (each acetyl CoA) results in: 2 CO2 molecules 3 NADH2 molecules 1 FADH2 molecules 1 ATP molecules  Citric Acid (Krebs) Cycle Therefore each pyruvic acid produces: (add CO2 & NADH2 from transition) 3 CO2 molecules 4 NADH molecules 1 FADH2 molecules 1 ATP molecules  Citric Acid (Krebs) Cycle Therefore each Glucose molecule produces (2 pyruvic acid molecules per glucose) 6 CO2 molecules 8 NADH molecules 2 FADH2 molecules 2 ATP molecules  CO2 SP SP 7.4 An Overview of Aerobic Cellular Respiration  Oxidative Phosphorylation Directly uses O2 Consists of 2 processes 1.) ETC 2.) Chemiosmosis  Electron Transport Chain (ETC) NADH and FADH2 drop off H+ and the e- are split off and shuttled generating energy used to pump H+ out of the inner membrane into the intermembrane space. This creates an H+ (electrical gradient) across the inner membrane  Electron Transport Chain Inner membrane of mitochondria are composed of cytochromes or respiratory enzymes. Cytochromes: proteins with heme group & Fe (cyt b, cyt a) Coenzyme Q: non protein carrier Energy from electrons pumps H+ into intermembrane space ETC Animation  Chemiosmosis ATP synthesis occurs when H+ diffuse back into the matrix through a special type of H+ channel in the inner membrane Requires ATP synthase which uses energy of protons to make ATP  Chemiosmosis Each NADH provides energy to pump 10 H+ into intermembrane space. Every 4 H+ running through “turbine” generates 1 ATP. ETC Animation  Chemiosmosis Oxidation of each NADH = 2.5 ATP Oxidation of each FADH2 = 1.5 ATP ETC Animation  ETC & chemiosmosis NAD & FAD 26-28 by op Aerobic Cellular Respiration - Summary Total ATP production from one glucose molecule: Glycolysis: 2 ATP via substrate level phosphorylation............. 2 2 NADH (ETC: X 2.5 in heart -1.5 skeletal).......... 3 (5) Transition Reaction 2 NADH (ETC: X 2.5)............................. 5 Citric Acid Cycle 3 NADH X 2 = 6 NADH2 (ETS: X 2.5 in ETC)........... 15 1 FADH2 X 2 = 2 FADH2 (ETS: X 1.5 in ETC)........... 3 1 ATP X 2 via substrate level phosphorylation)....... …. 2 30 (32 heart) Summarize the Major Steps of CR Glycolysis Transition Step Citric Acid Cycle OXPHOS/ETC/C hem Location in cell Starting Reactants End Products ATP net yield CO2 produced H2O produced Summarize the Major Steps of CR Glycolysis Transition Step Citric Acid Cycle OXPHOS/ETC/C hem Location in cell Cytoplasm Matrix of Matrix of Inner membrane Mitochondria Mitochondria of Mitochondria Starting Reactants End Products ATP net yield CO2 produced H2O produced Summarize the Major Steps of CR Glycolysis Transition Step Citric Acid Cycle OXPHOS/ETC/C hem Location in cell Cytoplasm Matrix of Matrix of Inner membr. Mitochondria Mitochon. Mito. Starting Glucose, NAD, 2 pyruvic acid, Acteyl CoA, NADH, FADH2, Reactants ATP Coenzyme A, NAD, FAD O2 NAD End Products ATP net yield CO2 produced H2O produced Summarize the Major Steps of CR Glycolysis Transition Step Citric Acid Cycle OXPHOS/ETC/C hem Location in cell Cytoplasm Matrix of Matrix of Inner membr. Mitochondria Mitochon. Mito. Starting Glucose, NAD, 2 pyruvic acid, Acteyl CoA, NADH, FADH2, Reactants ATP Coenzyme A, NAD, FAD O2 NAD End Products 2 pyruvic acid, CO2, NADH, NADH, FADH2, NAD, FAD, H2O, NADH, ATP Acetyl CoA CO2, ATP ATP ATP net yield CO2 produced H2O produced Summarize the Major Steps of CR Glycolysis Transition Step Citric Acid Cycle OXPHOS/ETC/C hem Location in cell Cytoplasm Matrix of Matrix of Inner membr. Mitochondria Mitochon. Mito. Starting Glucose, NAD, 2 pyruvic acid, Acteyl CoA, NADH, FADH2, Reactants ATP Coenzyme A, NAD, FAD O2 NAD End Products 2 pyruvic acid, CO2, NADH, NADH, FADH2, NAD, FAD, H2O, NADH, ATP Acetyl CoA CO2, ATP ATP ATP net yield 2 SP 0 2 SP 26-28 OP CO2 produced H2O produced Summarize the Major Steps of CR Glycolysis Transition Step Citric Acid Cycle OXPHOS/ETC/C hem Location in cell Cytoplasm Mitochondria Matrix of Inner membr. Mitochon. Mito. Starting Glucose, NAD, 2 pyruvic acid, Acteyl CoA, NADH, FADH2, Reactants ATP Coenzyme A, NAD, FAD O2 NAD End Products 2 pyruvic acid, CO2, NADH, NADH, FADH2, NAD, FAD, H2O, NADH, ATP Acetyl CoA CO2, ATP ATP ATP net yield 2 SP 0 2 SP 26-28 OP CO2 produced No Yes Yes No H2O produced YES No No Yes  Med-Note 7.1 Muscle Fatigue Muscle fatigue = decrease in strength  Med-Note 7.1 Muscle Fatigue Lactate & phosphate accumulation in muscle may cause muscle fatigue Evidence also shows a loss of Ca++ from the muscle occurs which weakens contractions BIO-Note 7.2 The Physiology of Exercise  BIO-Note 7.2 The Physiology of Exercise § Exercise classified by the duration and 1. Explosive maximal effort exercise with a duration of only 6 seconds intensity 2. High intensity efforts of all-out intensity for durations of 6 seconds to one minute 3. Endurance intensive efforts for over one minute 4. Low intensity exercise for longer durations High Intensity Exercise § ATP generated via glycolysis § Lactate formed and travels to liver for Cori Cycle Onset Blood Lactate Accumulation (OBLA) § AT (anerobic threshold) AT § Increased blood lactate levels § Cardiac muscle not suited for anaerobic OnsetBloodLactateAccumulation  Oxygen Deficit At the beginning of the exercise  Oxygen Debt During recovery after exercise Increase Respiratory Rate to provide more O2 to body. 1.) Buffer lactic acid 2.) Allow liver to convert lactic acid back into glucose BIO-NOTE 7.3 Glycogen Metabolism BIO-NOTE 7.3 Glycogen Metabolism BIO-NOTE 7.3 Glycogen Metabolism Glycogenesis occurs in skeletal muscle and liver Glucose → glucose 6-PO4 → glycogen If glucose levels remain high, then the glucose 6-PO4 will convert glycerol and triglycerides (fat) for fat storage called lipogenesis  BIO-NOTE 7.3 Glycogen Metabolism Glycogenolysis: -occurs directly in the liver Glycogen → Glucose 6-PO4 → Glucose (e-phophatase) -occurs indirectly in skeletal muscle Glycogen → Glucose 6-PO4 → Pyruvic Acid → bloodstream to liver  BIO-NOTE 7.3 Glycogen Metabolism Gluconeogenesis: -occurs mainly in the liver Lipids → glycerol → glucose Proteins → amino acids → glucose  7.6 Other Organisms Metabolic Processes § Some organisms do not use O2, may lack enzymes, or not have enough O2 available § Obligate anaerobes  7.6 Other Organisms Metabolic Processes § Some bacteria use sulfate as final electron acceptor § Forms H2S as end produce  Fermentation § Fermentation: 1.) Alcohol Fermentation 2.) Lactic Acid Fermentation  Alcohol Fermentation § Often used by yeast § Pyruvic acid → ethanol and CO2 and 2 ATP molecules § Products useful to us: bread baking (CO2 makes bread rise) § Brewing industry: alcohol Fermentation in Beer  Fermentation Lactic Acid Fermentation § Used in yogurt, sour cream, cheeses § During anaerobic activities lactic acid causes muscle fatigue and pain Fermentation