Cellular Respiration 1 2024 PDF

CELLULAR RESPIRATION PHOTORESPIRATION  The Calvin cycle occurs in the stroma of the chloroplast Thylakoids Stroma 1. Solar energy absorbed...

CELLULAR RESPIRATION PHOTORESPIRATION  The Calvin cycle occurs in the stroma of the chloroplast Thylakoids Stroma 1. Solar energy absorbed Calvin 2. Water is split to Cycle release O2 1. CO2 absorbed 3. ATP and NADPH 2. CO2 reduced to produced sugar using ATP, © 2010 Nature Education All rights reserved. NADPH …unless In high temperatures Plants close their stomata to prevent water loss Oxygen accumulates from light reactions  Rubisco also has a major flaw Instead of always using CO2 as a substrate, sometimes uses O2 instead https://www.khanacademy.org  3 carbons RuBP 5 carbons 6 carbons 3PGA 3-Phosphoglycerate  O2 RuBP 5 carbons 6 carbons 3PGA A small 2 Carbon waste ATP During process ADP CO2 is released  Photorespiration When O2 > CO2 Rubisco fixes oxygen to RubP Produces CO2 instead No Sugar! Which molecule is the ultimate electron acceptor in the whole Photosynthesis reaction? Questions? CELLULAR RESPIRATION Oxidation-reduction reactions involve the gain or loss of electrons or H+ ions O.I.L. R.I.G. Oxidized Reduced Is Is Loss Gain Electron Carriers: NADP+ shuttle electrons in Chloroplasts NADP+ NADPH NADPH NADP+ Electron Carriers for Cellular Respiration: R R R R  R R R R FAD FADH2 Electron Carriers: coenzymes NAD+ and FAD shuttle electrons FAD FADH2 FADH2 FAD Electron Carriers: coenzymes NAD+ and FAD shuttle electrons Electron Carrier in PHOTOSYNTHESIS: coenzymes NADP+ shuttles electrons NADP+ NADPH NADPH NADP+  R R R R FAD FADH2 Cellular respiration: Cells acquire energy by catabolizing nutrient molecules produced by autotrophs. There are 4 phases of cellular respiration 1. Glycolysis 2. Pyruvate Oxidation 3. The Citric Acid Cycle (TCA Cycle, Krebs Cycle) 4. The Electron Transport Chain (ETC)  Nature favors a constant increase in entropy Entropy = the amount of disorganization More organized Less organized More potential Less potential Energy Energy Less Stable More stable Glucose H2O and CO2 Why not just have a single exergonic reaction? + ATP Maximization of net Energy ATP + ATP Four interconnected processes that together convert most of the chemical energy in glucose to chemical energy in ATP Maximization of net Energy IN THE CYTOPLASM: GLYCOLYSIS  Glycolysis has two anaerobic steps Energy Investment Energy Harvest  Energy Investment G3P intermediate G3P Two phosphorylation events Energy Investment G3P intermediate G3P Energy Investment G3P intermediate G3P Where have we seen this molecule before?  The energy-investment step uses 2 ATP to phosphorylate Glucose  Energy Harvest G3P 3-PGA  Energy Harvest End of investment 3-PGA G3P 3-PGA G3P  The energy-harvesting steps generate 2 NADH, 4 ATP, and 2 Pyruvate 2 NAD+ + 2 H+ à 2 NADH  Energy Harvest End of investment 3-PGA G3P 3-PGA G3P  RUBISCO 1 Carbon Fixation Glyceraldehyde-3-phosphate  Energy Harvest End of investment 3-PGA G3P Substrate-Level Phosphorylation 3-PGA G3P Substrate-Level Phosphorylation  Substrate-level phosphorylation Occurs when an enzyme forms ATP by transferring a phosphate group from a phosphorylated substrate to ADP. ATP is NOT formed by ATP synthase NOT ATP Synthase  Substrate-level phosphorylation Occurs when an enzyme forms ATP by transferring a phosphate group from a phosphorylated substrate to ADP. ATP is NOT formed by ATP synthase NOT ATP Synthase Glycolysis overall: Inputs Outputs Glucose (6-C) 2 Pyruvate (3-C) 2 NAD+ 2 NADH 2 ATP 2 ADP 4 ADP + 4 Pi 4 ATP (2 net gain) Investment step Energy Investment G3P intermediate G3P Second phosphorylation event Can be regulated by ATP Regulation of Glycolysis Low levels of Cellular ATP ATP has lower affinity to the enzyme’s regulatory site ATP has higher affinity to the enzyme's active site + ATP + ADP Regulation of Glycolysis Surplus of Cellular ATP + ATP + ADP Regulation of Glycolysis Feedback inhibition example When concentrations are low, ATP binds only to the active site. As ATP concentrations increase it also starts to bind at the regulatory site. When ATP binds at this second location, ATP acts as an allosteric inhibitor. The whole cellular respiration stops. Regulation of Glycolysis Feedback inhibition example When concentrations are low, ATP binds only to the active site. As ATP concentrations increase it also starts to bind at the regulatory site. When ATP binds at this second location, ATP acts as an allosteric inhibitor. The whole cellular respiration stops. ATP is the final product of Cellular respiration. The cell gets feedback that there is a surplus of ATP, and it’s better to stop. Feedback inhibition Occurs when the product of a metabolic pathway inhibits an enzyme that functions early in the pathway. Questions? INSIDE THE MITOCHONDRIA Pyruvate Oxidation Pyruvate Oxidation occurs in the mitochondrial matrix Pyruvate is small enough to diffuse to the mitochondrial matrix *Cryo-electron tomography of mitochondria Pyruvate Oxidation prepares products of glycolysis to enter the citric acid cycle Pyruvate Oxidation prepares products of glycolysis to enter the citric acid cycle Pyruvate Oxidation prepares products of glycolysis to enter the citric acid cycle 2 2 2 2 2 2 Pyruvate Oxidation overall: Inputs Outputs 2 pyruvate (3-C) 2 acetyl-CoA 2 NAD+ 2 NADH 2 CO2 Glycolysis overall: Pyruvate Oxidation overall: Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 2 NADH 2 NADH 2 ADP 2 CO2 2 net ATP THE CITRIC ACID CYCLE  The citric acid cycle also in the mitochondrial matrix  RUBISCO 1 Carbon Fixation Calvin Cycle Glyceraldehyde-3-phosphate Krebs Cycle  6 Carbon 5 Carbon 4 Carbon In each table select two student leaders. Only leaders please access the link provided in the announcement.  6 Carbon 5 Carbon 4 Carbon  + 3 1 1  + + 6 2 2 The citric acid cycle overall: Inputs Outputs 2 Acetyl-CoA 4 CO2 6 NAD+ 6 NADH 2 FAD 2 FADH2 2 ADP + 2 Pi 2 ATP Questions?  Glycolysis Pyruvate Citric acid Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 2 ATP  Glycolysis Pyruvate Citric acid Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 2 ATP 10 NADH TOTAL 2 FADH2 YIELD 4 SL ATP Lack of glucose???? Simplified version of Figure 9.3  THE ELECTRON TRANSPORT CHAIN (Oxidative Phosphorilation)  Starting molecule: ATP Pyruvate Citric acid Glycolysis Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 10 NADH 2 ATP 2 FADH2 TOTAL YIELD 4 SL ATP  ATP Maximization of net Energy ATP  Starting molecule: ATP Pyruvate Citric acid Glycolysis Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 10 NADH 2 ATP 2 FADH2 TOTAL YIELD 4 SL ATP  Starting molecule: ATP Pyruvate Citric acid Glycolysis Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 10 NADH 2 ATP Oxidative 2 FADH2 TOTAL Phosphorilation YIELD 4 SL ATP Khan Academy The electron transport chain occurs in the mitochondrial cristae (membrane) Outer membrane Inner membrane Intermembrane Matrix Inner membrane Outer membrane  Intermembrane ATP IV synthase III I II Matrix 1. NADH gets oxidized 1. NADH gets oxidized Intermembrane ATP IV synthase III I II Matrix 2. FADH2 gets oxidized 2. FADH2 gets oxidized at Complex II Intermembrane ATP IV synthase III I II Matrix 3. NADH causes more protons (H+) to be pumped than FADH2 3. NADH causes more protons (H+) to be pumped than FADH2 Intermembrane ATP IV synthase III I II Matrix 4. Complex IV holds ½ O2 and donates the electrons , the negative charge attracts 2 protons from the matrix 4. Complex IV holds ½ O2 and donates the electrons , the negative charge attracts 2 protons from the matrix Intermembrane ATP IV synthase III I II Matrix 5. H+ electrochemical gradient provides energy to ATP synthase 5. H+ electrochemical gradient provides energy to ATP synthase Intermembrane ATP IV synthase III I II Matrix  ATP synthase High concentration of Hydrogen Ions  Oxidative Phosphorylation? Intermembrane ATP IV synthase III I II Matrix 3. Oxidation of NADH causes more protons (H+) to be pumped than FADH2 Intermembrane ATP IV synthase III I II Therefore: 1 NADH 2.5 ATP 1 FADH2 1.5 ATP Matrix  Starting molecule: ATP Pyruvate Citric acid Glycolysis Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 10 NADH 2 ATP 2 FADH2 TOTAL ATP converter 1 NADH 2.5 ATP YIELD 4 SL ATP 1 FADH2 1.5 ATP  Starting molecule: ATP Pyruvate Citric acid Glycolysis Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 10 NADH TOTAL 2 ATP ATP converter 2 FADH2 YIELD 1 NADH 2.5 ATP 4 SL ATP 32 ATP 1 FADH2 1.5 ATP  Starting molecule: ATP Pyruvate Citric acid Glycolysis Oxidation cycle Outputs Outputs Outputs 2 Pyruvate (3-C) 2 acetyl-CoA 4 CO2 2 NADH 2 NADH 6 NADH 2 ADP 2 CO2 2 FADH2 2 net ATP 10 NADH TOTAL 2 ATP ATP converter 2 FADH2 YIELD 32 ATP1 NADH 2.5 ATP 4 ATP 32 ATP 1 FADH 1.5 ATP 2 4. Complex IV holds ½ O2 and donates the electrons , the negative charge attracts 2 protons from the matrix Intermembrane ATP IV synthase III I II Matrix Carbon Monoxide and Intermembrane Cyanide Inhibit Complex IV. What is the effect? ATP IV synthase III I II Matrix Carbon Monoxide and Cyanide competitive Intermembrane Inhibitors of Complex IV. What is the effect? ATP IV synthase III I II Matrix Carbon Monoxide and Cyanide competitive Intermembrane Inhibitors of Complex IV. What is the effect? ATP IV synthase III I II Oxygen cannot not accept electrons. Aerobic stages of respiration STOP Matrix Whenever there is a lack of oxygen the whole process stops Intermembrane ATP IV synthase III I II Matrix Anaerobic Cellular Respiration and FERMENTATION  Energy Investment G3P G3P Two phosphorylation events Energy Harvest G3P NADH and FADH2 need to be oxidated  Intermembrane ATP IV synthase III I II Not Oxygen! Matrix NADH and FADH2 need to be oxidated ?  Some organic molecule Anaerobic respiration Some organic molecule Iron or Nitrite  Some organic molecule Anaerobic respiration Some organic molecule H+ + CO2 CH4 + H2O Inorganic electron acceptor = Anaerobic respiration Some organic molecule Some organic molecule H+ + CO2 CH4 + H2O Iron or Nitrite NADH and FADH2 need to be oxidated ? Organic electron acceptor = Fermentation Beer and spirits are made through fermentation  Organic electron acceptor = Fermentation Yeasts and other fungi and bacteria + =  Organic electron acceptor = Fermentation Yeasts and other fungi and bacteria  Organic electron acceptor = Fermentation Skeletal muscle And Red Blood Cells