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Complete the warm-ups. You can cut these up for your note cards later. Oxidizing Food Molecules Energy: One way flow In from sun, Lost as heat Biochemicals constantly recycle Energy stored in food can be traced back to the sun Fuel molecules in food store solar energy in chemical bonds Animals depend on plants to convert solar energy to chemical energy This chemical energy is in the form of sugars and other organic molecules 4 Autotrophs - Producers - Plants and other organisms that make all their own organic matter from inorganic nutrients Heterotrophs – Consumers - Humans and other animals that cannot make organic molecules from inorganic ones 5 Both plants and animals perform cellular respiration Cellular respiration is a chemical process that harvests energy from organic molecules and occurs in the mitochondria The waste products of cellular respiration, CO2 and H2O, are used in photosynthesis 6 Citric Acid Cycle (matrix) ETC (inner membrane) When you exercise: Muscles need energy in order to perform work Your cells use oxygen to release energy from the sugar - glucose 8 Aerobic metabolism - When enough oxygen reaches cells to support energy needs - Maximum energy production Anaerobic metabolism When the demand for oxygen outstrips the body’s ability to deliver it Low energy production 9 Without enough oxygen, muscle cells break down glucose to produce lactic acid Lactic acid is associated with the “burn” accompanying heavy exercise If too much lactic acid builds up, your muscles give out 10 Allows your body to adapt to increased activity The body can increase its ability to deliver oxygen to muscles Long-distance runners wait until the final sprint to exceed their aerobic capacity 11 12 Cellular respiration Is the most prevalent and efficient catabolic pathway Consumes oxygen and organic molecules such as glucose Yields ATP Respiration: exergonic (releases E) C6H12O6 + 6O2 6H2O + 6CO2 + ATP (+ heat) Photosynthesis: endergonic (requires E) 6H2O + 6CO2 + Light C6H12O6 + 6O2 Respiration Photosynthesis Occurs in all organisms Occurs in only chlorophyll containing organisms Breaks down glucose Stores light energy as chemical energy in the bonds of glucose Releases carbon Produces glucose and dioxide, water, & ATP oxygen Exergonic Reaction Endergonic reaction 16 Cellular respiration can “burn” other kinds of molecules besides glucose: Carbs Fats Proteins Starch -> __??___ -> ATP 17 Cellular respiration and breathing are closely related Respiration exchange gases with its surroundings Cellular Respiration: exchanges these gases in the cells 18 Breathing Lungs Muscle cells Cellular Respiration 19 Chemical reactions that transfer electrons from one substance to another: oxidation-reduction reactions Oxidation: The loss of electrons and energy Reduction: The acceptance of electrons and energy Oxidizing agent: e- acceptor Reducing agent: e- donor 20 Electrons are striped from GLUCOSE (oxidized) Electrons meet up with Protons to form H atom H atoms are transferred to electron carriers: NAD+ to make NADH Eventually meeting up with oxygen (reduced) OILRIG!!! becomes oxidized Oxidation is a loss. Reduction is a gain. C6H12O6 + 6O2 6CO2 + 6H2O + Energy becomes reduced Glucose loses electrons (and hydrogens) Oxidation Glucose Oxygen Carbon dioxide Water Reduction Oxygen gains electrons (and hydrogens)] Electrons travel downhill in an energy-yielding tumble (analagous to gravity pulling objects) to find a more stable location. 22 STEP BY STEP If electron transfer is not stepwise - A large release of energy occurs. As in the reaction of hydrogen and oxygen to form water ETC: Passes electrons in a series of steps and uses the energy from the electron transfer to form ATP Cellular Respiration is a metabolic pathway, not a single reaction Many chemical reactions, both aerobic and anaerobic, are involved in the process of cellular respiration Lots of enzymes are required for the process to occur 24 Print Student Lyrics Glycolysis – occurs in cytoplasm Formation of Acetyl CoA The Krebs cycle – occurs in matrix of mitochondria (Oxidative Phosphorylation) Electron transport – occurs across the mitochondrial membrane 28 You have to spend money to make A ten-step process that occurs in the cytoplasm of the cell One glucose -> two molecules of pyruvic money!!!! acid or pyruvate (a 3-carbon molecule) Anaerobic process - proceeds whether or not O2 is present NET: 2 ATP per glucose molecule NET: 2 NADH per glucose (a co-enzyme that serves as a carrier for H+ ions liberated as glucose is oxidized.) The pyruvic acid diffuses into the inner compartment of the mitochondrion. Prepare pyruvic acid for entry into the next stage of respiration. Pyruvate (3 Carbon Molecule) Acetyl CoA (2 Carbon Molecule) CO2 and NADH produced Oxidized? Reduced? Occurs in mitochondrial matrix 2 Pyruvate -> 2 Acetyl CoA Citrate Net gain after 2 turns: 2 ATP, 2 FADH2 (electron carrier) Completes two turns through the cycle. CO2 released 4 CO2, 6 NADH, Note: The six original carbons from glucose have been released with carbon dioxide. NO CARBON REMAINS. Collection of proteins and carrier molecules embedded in inner membrane of mitochondria Does not make ATP directly The chain functions as a chemical machine that uses energy released by the “fall” of electrons to pump hydrogen ions across the inner mitochondrial membrane These ions store potential energy 2 H+ + ½ O2 H2O NADH and FADH2 “shuttle” electrons to the electron transport chain. The hydrogen atoms are split into hydrogen ion and electrons. H2 -> 2 H+ and 2eThey travel down until the reach the last electron carrier – oxygen. Oxygen combines with these electrons and hydrogens to form water. H2 -> 2 H+ and 2e- ATP SYNTHASE harness the proton-motive force (gradient of hydrogen ions) to phosphorylate ADP, forming ATP. H+ pumped from inner membrane to intermembrane space H+ pump through ATP Synthase (Enzyme) On the other side is ADP and P The pumping creates a gradient (H gradient or proton gradient) This potential energy creates ATP Chemiosmosis uses stored energy to drive cellular work Electron Transport Chain Chemiosmosis Occurs in inner membrane H+ ions pumped across of mitochondria inner mitochondrial membrane Produces 26-28 ATP by oxidative phosphorylation H+ diffuse through ATP via chemiosmosis synthase (ADP ATP) ATP YIELD PER GLUCOSE 30-32 (Lower than earlier textbooks) Mitochondrion Cytosol High-energy electrons carried mainly by NADH High-energy electrons carried by NADH Glycolysis Glucose 2 Pyruvic acid Krebs Cycle Electron Transport 41 Process Location Glycolysis Formation of Acetyl CoA Output ____ ATP (___ NET) ____ Pyruvates 2 NADH Transported into Mighty Mito 2 CO2 2 Acetyl CoA 2 NADH Krebs/Citric ____ ATP 6 NADH 2 FADH2 ETC: Oxidative Phosphorylation and Chemiosmosis ____ ATP 2 H2O ____ ATP Process Location Output Glycolysis Cytoplasm 4 ATP (2 NET) 2 Pyruvates 2 NADH Formation of Acetyl CoA Transported into Mighty Mito 2 CO2 2 Acetyl CoA 2 NADH Krebs/Citric Matrix of Mito 2 ATP 6 NADH 2 FADH2 ETC: Oxidative Phosphorylation and Chemiosmosis Inner Mito Mb 26-28 ATP 2 H2O The MOST NADH and FADH2 30-32 ATP Some of your cells can actually work for short periods without oxygen (anaerobic respiration) For example, muscle cells can produce ATP under anaerobic conditions 45 They can make ATP with / without oxygen They have enough ATP to support activities such as quick sprinting for about 5 seconds A secondary supply of energy (creatine phosphate) can keep muscle cells going for another 10 seconds To keep running, your muscles must generate ATP by the anaerobic process of fermentation 46 Without O2 Fermentation Keep glycolysis going by regenerating NAD+ Occurs in cytosol No oxygen needed Creates ethanol [+ CO2] or lactate 2 ATP (from glycolysis) O2 present Respiration Release E from breakdown of food with O2 Occurs in mitochondria O2 required (final electron acceptor) Produces CO2, H2O and up to 32 ATP Alcohol fermentation Lactic acid fermentation Pyruvate Ethanol + Pyruvate Lactate CO2 Ex. bacteria, yeast Used in brewing, winemaking, baking Ex. fungi, bacteria, human muscle cells Used to make cheese, yogurt, acetone, methanol Note: Lactate build-up does NOT causes muscle fatigue and pain (old idea) 2 ADP+ 2 Glycolysis 2 NAD 2 NAD Glucose 2 Pyruvic acid + 2 H 2 Lactic acid Lactic acid fermentation 49 2 ADP+ 2 2 CO2 released 2 ATP Glycolysis 2 NAD 2 NAD Glucose 2 Pyruvic acid 2 Ethyl alcohol + 2 H Alcoholic fermentation 50 Obligate Anaerobes – only ferment, can’t survive with oxygen Facultative anaerobes – both (yeast/bacteria) 51 aerobic cellular respiration (with O2) ENERGY glycolysis anaerobic (without O2) (cytosol) mitochondria Fermentation (cytosol) pyruvate oxidation ethanol + CO2 (yeast, some bacteria) citric acid cycle ETC chemiosmosis lactic acid (animals) oxidative phosphorylation What if you have high levels of ATP in the cell? Turn in your Case Study Cellular Respiration Pre-Lab Quiz Review Cellular Respiration, Finish Notes, Animation Take out Enzyme Lab and Pre-Lab, Leave on desk. Warm Up: Whisper Down the Lane *Prize* Peer Grading Metabolism FRQs (A, B, C) What if you have high levels of ATP in the cell? Regulatory allosteric enzyme in glycolysis When ATP levels are high in the cell, the cell no longer needs metabolic energy production to occur. In this case, PFK's activity is inhibited by allosteric regulation by ATP itself, closing the valve on the flow of carbohydrates through glycolysis. Recall that allosteric regulators bind to a different site on the enzyme than the active (catalytic) site. Thus ATP binds in two places on PFK: in the active site as a substrate and in the regulatory site as a negative modulator. 8 Steps Each catalyzed by a different enzyme First step synthesized by citrate synthase Acetyl Co-A joins Oxaloacetate to make citrate Transferring of carbon atoms and electrons We see lots of oxidation and reduction occurring This step makes the majority of NADH and FADH2 1 ATP is generated per turn, 2 turns total Release of CO2 (No more carbon left in the pathway) Electron to the next one! Electrons fall “downhill” losing a small amount of energy at each step Final destination? Oxygen – which has a high affinity for electrons Most of the ATP is produced during this step. As electrons are relayed and extracted. Energy coupling: Chemiosmosis couples electron transport to ATP synthesis Glycolysis is the most widespread metabolic pathway today No membrane-bound organelles (Prokaryotes) Ancient organisms probably used glycolysis exclusively - long before oxygen was present in our environment Oldest fossils 3.5 billion years old Oxygen available 2.7 billion years ago Cyanobacteria http://faculty.ccbcmd.edu/~gkaiser/biotutor ials/cellresp/etsch.html Use the Q-Chart to create three leveled questions about cellular respiration. I need a large pool of questions so please make your own and do not copy from other students. I want to know YOUR questions, not your neighbor. Could be something you really don’t know. Or pose a question that you think would be good for others. Agenda: Cell Respiration Lab Part 1 HW: Identify 3 Enzymes with their matching substrates and products as well as any medical implications of someone missing this enzyme. AFTER SCHOOL CELL RESPIRATION REVIEW Agenda: Finish Cellular Respiration Part 1 Write-Up Due Tomorrow