Cell Respiration Honors 2025 Student Version PDF

Cellular Respiration HOW CELLS HARVEST CHEMICAL ENERGY ATP  Introduction to Cellular Respiration Cell respiration is how we derive energy from our food, specifically glucose Nearly all cells in our body break down sugars for ATP production The aerobic harvesting...

Cellular Respiration HOW CELLS HARVEST CHEMICAL ENERGY ATP  Introduction to Cellular Respiration Cell respiration is how we derive energy from our food, specifically glucose Nearly all cells in our body break down sugars for ATP production The aerobic harvesting of energy from sugar is called cellular respiration Glucose Oxygen gas Carbon Water Energy dioxide 38 ATPs  Cellular Respiration is a redox reaction ____ of hydrogen atoms Energy Glucose ____ of hydrogen atoms Glucose → Carbon dioxide ○ Oxygen → Water ○  Breathing, cellular respiration & ATP Breathing supplies O2 to the cells and cellular respiration will occur Cell respiration breaks down glucose and stores the energy into ATP molecules ○ Used for cellular work CO2 is released as a byproduct and exhaled Introduction Animation  What is ATP? ATP: adenosine triphosphate ○ Currency of biological energy ○ Where is the energy stored? When ATP is hydrolyzed, it gives off energy Exergonic When ATP is created, energy is stored! ○ Endergonic  How can we generate ATP ? Two different ways: High H+ concentration ○ 1. Chemiosmosis ATP synthase uses ○ 2. Substrate-level phosphorylation H+ gradient energy to make ATP Membrane Chemiosmosis: Electron ○ ATP synthase (an enzyme) transport chain synthesizes ATP using the energy stored in concentration ATP synthase gradients of H+ ions across membranes Energy from Low H+ ○ Occurs in a membrane concentration  Cellular Respiration HOW CELLS HARVEST CHEMICAL ENERGY ATP  Introduction to Cellular Respiration Cell respiration is how we derive energy from our food, specifically glucose Nearly all cells in our body break down sugars for ATP production The aerobic harvesting of energy from sugar is called cellular respiration Glucose Oxygen gas Carbon Water Energy dioxide 38 ATPs  Cellular Respiration is a redox reaction ____ of hydrogen atoms Energy Glucose ____ of hydrogen atoms Glucose → Carbon dioxide ○ Oxygen → Water ○  Breathing, cellular respiration & ATP Breathing supplies O2 to the cells and cellular respiration will occur Cell respiration breaks down glucose and stores the energy into ATP molecules ○ Used for cellular work CO2 is released as a byproduct and exhaled Introduction Animation  What is ATP? ATP: adenosine triphosphate ○ Currency of biological energy ○ Where is the energy stored? When ATP is hydrolyzed, it gives off energy Exergonic When ATP is created, energy is stored! ○ Endergonic  How can we generate ATP ? Two different ways: High H+ concentration ○ 1. Chemiosmosis ATP synthase uses ○ 2. Substrate-level phosphorylation H+ gradient energy to make ATP Membrane Chemiosmosis: Electron ○ ATP synthase (an enzyme) transport chain synthesizes ATP using the energy stored in concentration ATP synthase gradients of H+ ions across membranes Energy from Low H+ ○ Occurs in a membrane concentration  Generating ATP continued… 2. Substrate-level phosphorylation ○ An enzyme transfers a phosphate group from a substrate to ADP ○ Occurs without a membrane  Cell Respiration occurs in 3 stages 1. Glycolysis occurs in the cytoplasm of the cell 2. Krebs cycle occurs in the mitochondria 3. Electron transport chain occurs in the mitochondria High-energy electrons carried by NADH GLYCOLYSIS ELECTRON Glucose Pyruvic KREBS TRANSPORT CHAIN acid CYCLE AND CHEMIOSMOSIS Cytoplasm Mitochondrion  Glycolysis Breaking DOWN OF Sugar  Glycolysis: breaking down of glucose Process by which a glucose molecule is broken down into 2 molecules of pyruvic acid. How much ATP is made? ○ Must invest 2 molecules of ATP to get the reaction started. ○ During the reaction, 4 ATP are created = ○ Net gain of 2 ATP  Glycolysis also produces NADH NADH is an electron carrier NAD+ + H+ + 2e-= NADH Oxidation or Reduction?  After Glycolysis… Products of glycolysis: ○ 2 ATP ○ Substrate level phosphorylation ○ NADH → goes to ETC ○ 2 pyruvic acid At the end of glycolysis, 90% of chemical energy that is available in glucose is still unused and locked in pyruvic acid. In the presence of oxygen, pyruvic acid passes to the Krebs Cycle in the mitochondria. Glycolysis Animation  Mitochondria: Site of Aerobic Respiration Krebs Cycle- ○ Matrix ETC- ○ Inner mitochondrial membrane  Krebs Cycle COMPLETES THE OXIDATION OF GLUCOSE GENERATES MANY NADH AND FADH2 MOLECULES OCCURS IN THE MATRIX OF THE MITOCHONDRIA  Krebs Cycle Krebs cycle is a series of reactions in which enzymes strip away electrons and H+ from the organic molecule and store them in electron carriers: ○ NADH and FADH2 FAD + 2H+ + 2e- = FADH2 Pyruvate is broken down releasing CO2 as byproduct to exhale  Energy Tallies from Krebs Cycle 2 ATP molecules ○ substrate-level phosphorylation NADH→ goes to ETC FADH2→ goes to ETC The electron carriers will go to the electron transport chain and generate HUGE amounts of ATP Krebs Animation 3:40 Electron Transport Chain CHEMIOSMOSIS POWERS ATP PRODUCTION  ETC & Chemiosmosis NADH and FADH2 release electrons into ETC As electrons move down the chain, H+ ions are pumped across the membrane H+ then go down the concentration gradient through ATP synthase ○ forming ATP  Electron Transport Chain: where do the electrons go? High energy electrons from NADH and FADH2 travel down the electron transport chain to an oxygen atom ○ At the end of ETC, an enzyme combines the electrons with H+ ions and oxygen to form WATER Oxygen is the final 2e- + 2 H+ + ½ O2 → H2O electron acceptor  REVIEW: Each glucose yields up to 38 molecules of ATP Cytoplasmic fluid Mitochondrion Electron shuttle across membranes GLYCOLYSIS 2 ELECTRON 2 KREBS TRANSPORT Glucose Acetyl Pyruvic CYCLE CHAIN AND CoA CHEMIOSMOSIS acid by substrate-level used for shuttling by substrate-level by chemiosmotic phosphorylation electrons from NADH phosphorylation phosphorylation made in glycolysis Maximum per glucose: ETC Cell Respiration Overview Video animation Anaerobic Respiration WITHOUT _______ Why is oxygen needed for the ETC and Krebs?! Without oxygen, only glycolysis can occur, why? Cyanide: 3:30  Fermentation is an anaerobic alternative to aerobic respiration After glycolysis, if there is no oxygen then fermentation occurs. Fermentation releases energy from food molecules by producing small amounts of ATP in the absence of oxygen. How much ATP? Glucose Pyruvic acid Glycolysis will stop when all NAD+ electron carriers are full…how can NAD + be replenished?  Fermentation must convert NADH to NAD + During fermentation, cells will convert NADH back into NAD+ by passing high energy electrons back to pyruvic acid. By converting NADH to NAD+, glycolysis can continue and small amounts of ATP (2) are created. Two types: 1. Alcoholic Fermentation 2. Lactic Fermentation Alcoholic Fermentation In alcoholic fermentation, pyruvic acid is converted to CO2 and ethyl alcohol (ethanol) ○ This recycles NAD+ to keep glycolysis working GLYCOLYSIS 2 pyruvic 2 Ethanol Glucose acid ○ Pyruvic acid + NADH → ethyl alcohol + CO2 + NAD+  Lactic Acid Fermentation In lactic acid fermentation, pyruvic acid is converted to lactic acid ○ This recycles NAD+ to keep glycolysis working ○ Pyruvic acid + NADH → lactic acid + NAD+  Lactic Acid Buildup During strenuous exercise, our cells require energy faster than our bodies can deliver oxygen Lactic Acid Fermentation (anaerobic): Our body begins to convert pyruvic acid into lactic acid to continue glycolysis to generate ATP. ○ lactic acid builds up at high levels in our muscles ○ High lactic acid = high acidity = pain and burning sensation Fermentation Review  Aerobic vs. Anaerobic Respiration Aerobic Anaerobic Yes No Oxygen Required? Processes Included? Glycolysis, krebs, ETC Glycolysis, fermentation (glycolysis, krebs, ETC, fermentation) Cytoplasm,mitochondria Cytoplasm Location in cell # of ATP created per 38 2 glucose molecule  Carbon Cycle Review All organisms have the ability to harvest energy (ATP) from organic molecules (glucose) However, only ______ perform photosynthesis  Photosynthesis vs. Cellular Respiration Photosynthesis Cell Respiration Function Location Reactants Products Equation  Generating ATP continued… 2. Substrate-level phosphorylation ○ An enzyme transfers a phosphate group from a substrate to ADP ○ Occurs without a membrane  Cell Respiration occurs in 3 stages 1. Glycolysis occurs in the cytoplasm of the cell 2. Krebs cycle occurs in the mitochondria 3. Electron transport chain occurs in the mitochondria High-energy electrons carried by NADH GLYCOLYSIS ELECTRON Glucose Pyruvic KREBS TRANSPORT CHAIN acid CYCLE AND CHEMIOSMOSIS Cytoplasm Mitochondrion  Glycolysis Breaking DOWN OF Sugar  Glycolysis: breaking down of glucose Process by which a glucose molecule is broken down into 2 molecules of pyruvic acid. How much ATP is made? ○ Must invest 2 molecules of ATP to get the reaction started. ○ During the reaction, 4 ATP are created = ○ Net gain of 2 ATP  Glycolysis also produces NADH NADH is an electron carrier NAD+ + H+ + 2e-= NADH Oxidation or Reduction?  After Glycolysis… Products of glycolysis: ○ 2 ATP ○ Substrate level phosphorylation ○ NADH → goes to ETC ○ 2 pyruvic acid At the end of glycolysis, 90% of chemical energy that is available in glucose is still unused and locked in pyruvic acid. In the presence of oxygen, pyruvic acid passes to the Krebs Cycle in the mitochondria. Glycolysis Animation  Mitochondria: Site of Aerobic Respiration Krebs Cycle- ○ Matrix ETC- ○ Inner mitochondrial membrane  Krebs Cycle COMPLETES THE OXIDATION OF GLUCOSE GENERATES MANY NADH AND FADH2 MOLECULES OCCURS IN THE MATRIX OF THE MITOCHONDRIA  Krebs Cycle Krebs cycle is a series of reactions in which enzymes strip away electrons and H+ from the organic molecule and store them in electron carriers: ○ NADH and FADH2 FAD + 2H+ + 2e- = FADH2 Pyruvate is broken down releasing CO2 as byproduct to exhale  Energy Tallies from Krebs Cycle 2 ATP molecules ○ substrate-level phosphorylation NADH→ goes to ETC FADH2→ goes to ETC The electron carriers will go to the electron transport chain and generate HUGE amounts of ATP Krebs Animation 3:40 Electron Transport Chain CHEMIOSMOSIS POWERS ATP PRODUCTION  ETC & Chemiosmosis NADH and FADH2 release electrons into ETC As electrons move down the chain, H+ ions are pumped across the membrane H+ then go down the concentration gradient through ATP synthase ○ forming ATP  Electron Transport Chain: where do the electrons go? High energy electrons from NADH and FADH2 travel down the electron transport chain to an oxygen atom ○ At the end of ETC, an enzyme combines the electrons with H+ ions and oxygen to form WATER Oxygen is the final 2e- + 2 H+ + ½ O2 → H2O electron acceptor  REVIEW: Each glucose yields up to 38 molecules of ATP Cytoplasmic fluid Mitochondrion Electron shuttle across membranes GLYCOLYSIS 2 ELECTRON 2 KREBS TRANSPORT Glucose Acetyl Pyruvic CYCLE CHAIN AND CoA CHEMIOSMOSIS acid by substrate-level used for shuttling by substrate-level by chemiosmotic phosphorylation electrons from NADH phosphorylation phosphorylation made in glycolysis Maximum per glucose: ETC Cell Respiration Overview Video animation Anaerobic Respiration WITHOUT _______ Why is oxygen needed for the ETC and Krebs?! Without oxygen, only glycolysis can occur, why? Cyanide: 3:30  Fermentation is an anaerobic alternative to aerobic respiration After glycolysis, if there is no oxygen then fermentation occurs. Fermentation releases energy from food molecules by producing small amounts of ATP in the absence of oxygen. How much ATP? Glucose Pyruvic acid Glycolysis will stop when all NAD+ electron carriers are full…how can NAD + be replenished?  Fermentation must convert NADH to NAD + During fermentation, cells will convert NADH back into NAD+ by passing high energy electrons back to pyruvic acid. By converting NADH to NAD+, glycolysis can continue and small amounts of ATP (2) are created. Two types: 1. Alcoholic Fermentation 2. Lactic Fermentation Alcoholic Fermentation In alcoholic fermentation, pyruvic acid is converted to CO2 and ethyl alcohol (ethanol) ○ This recycles NAD+ to keep glycolysis working GLYCOLYSIS 2 pyruvic 2 Ethanol Glucose acid ○ Pyruvic acid + NADH → ethyl alcohol + CO2 + NAD+  Lactic Acid Fermentation In lactic acid fermentation, pyruvic acid is converted to lactic acid ○ This recycles NAD+ to keep glycolysis working ○ Pyruvic acid + NADH → lactic acid + NAD+  Lactic Acid Buildup During strenuous exercise, our cells require energy faster than our bodies can deliver oxygen Lactic Acid Fermentation (anaerobic): Our body begins to convert pyruvic acid into lactic acid to continue glycolysis to generate ATP. ○ lactic acid builds up at high levels in our muscles ○ High lactic acid = high acidity = pain and burning sensation Fermentation Review  Aerobic vs. Anaerobic Respiration Aerobic Anaerobic Yes No Oxygen Required? Processes Included? Glycolysis, krebs, ETC Glycolysis, fermentation (glycolysis, krebs, ETC, fermentation) Cytoplasm,mitochondria Cytoplasm Location in cell # of ATP created per 38 2 glucose molecule  Carbon Cycle Review All organisms have the ability to harvest energy (ATP) from organic molecules (glucose) However, only ______ perform photosynthesis  Photosynthesis vs. Cellular Respiration Photosynthesis Cell Respiration Function Location Reactants Products Equation