Cellular Respiration: Overview, Glycolysis, Aerobic Respiration | Mrs. Hoskins PDF

By Mrs. Hoskins SB1. Obtain, evaluate, and communicate information to analyze the nature of the relationships between structures and functions in living cells. e. Ask questions to investigate and provide explanations about the roles of photosynthesis and respiration in the cycling of...

By Mrs. Hoskins SB1. Obtain, evaluate, and communicate information to analyze the nature of the relationships between structures and functions in living cells. e. Ask questions to investigate and provide explanations about the roles of photosynthesis and respiration in the cycling of matter and flow of energy within the cell (e.g., single-celled alga).  Overview Goal of cellular respiration = to convert the chemical energy in food (glucose) to chemical energy stored in ATP. We use carbohydrates 1st for energy, but any food can be processed/broken down as a source of energy. Chemical equation: C6H12O6 + 6O2 🡪 6H2O + 6CO2 + Energy (ATP)  Overview C6H12O6 + 6O2 6CO2 + 6H2O + energy Reactants = ingredients – C6H12O6 (glucose) and O2 (oxygen) Products = results – CO2 (carbon dioxide) and H2O (water) Note: Energy is released in the form of ATP from this process but isn’t considered a product. Structure of Mitochondria Cellular respiration takes place in the mitochondria which has 2 main parts: Inner membrane: folded membranes Matrix: fluid-like substance that fills inner membrane the space  Glycolysis The first stage in cellular respiration is glycolysis, the breakdown of glucose. Purpose = 10-step process of splitting the 6- carbon molecule of glucose in half to form 2 3- carbon molecules called pyruvate. This occurs in the cytoplasm, and requires no oxygen, meaning it is anaerobic. Produces a net of 2 ATP and a 2 NADH. - 1 glucose 🡪 2 pyruvate molecules and 4 ATP, but it uses 2 to get the process going, so it only nets 2 ATP  Decision Time After glycolysis, the cell must make a decision. If oxygen is present, then the cell will go through a two-step process known as aerobic respiration to obtain energy. If oxygen is NOT present, then the cell will go through the process of anaerobic respiration, aka fermentation, in order to obtain energy. O2 present Aerobic Respiration Glycolysis O2 absent Anaerobic Respiration  O2 is Available: Aerobic Respiration 1. Citric Acid Cycle (aka Krebs Cycle) Purpose = make electron carriers NADH and FADH2 to move on to the ETC Location = Mitochondrial Matrix Process: 8 steps of chemical rxns where 2 pyruvate molecules from glycolysis are chemically converted to make 2 ATP (and some NADH and FADH2) - Releases CO2 as a waste product  O2 is Available: Aerobic Respiration 1. Citric Acid Cycle (aka Krebs Cycle) Details = - Pyruvate from glycolysis are converted into acetyl-CoA, which will then enter the Citric Acid Cycle - NAD+ and FAD act as electron carriers and become NADH and FADH2 which carry e- into the final step - The cycle happens 2x!! Each time, 1 pyruvate 🡪 4 NADH, 1 ATP, 1 FADH , and 2 3 CO2 Therefore, TOTAL = 8 NADH, 2 ATP, 2 FADH and 6 2 CO2  O2 is Available: Aerobic Respiration 2. Electron Transport Chain (oxidative phosphorylation and chemiosmosis) - Remember, chemiosmosis combines electron transport to ATP synthesis Location = Inner membrane of the mitochondria (called cristae)  O2 is Available: Aerobic Respiration 2. Electron Transport Chain (oxidative phosphorylation and chemiosmosis) Process: - A series of reactions using the e - and hydrogens carried by NADH and FADH2 formed in the Krebs Cycle - Enzyme ATP Synthase helps to assemble ATP - Final electron acceptor after the e - have gone down the ETC is oxygen Oxygen combines with e- and H+ to make water. - Makes 34 ATP and H2O (when hydrogen bonds to oxygen) - **Most ATP comes from this step!!**  O2 is Available: Aerobic Respiration  Think about it… What similarities are there between photosynthesis and cellular respiration? PHOTOSYNTHESIS CELLULAR RESPIRATION Equation 6CO2 + 6H2O 🡪 C6H12O6 + 6O2 C6H12O6 + 6O2 🡪 6CO2 + 6H2O + energy (ATP) Type of Rxn Endothermic Exothermic Reactants Water and Carbon Dioxide Glucose and Oxygen Products Glucose and Oxygen Water and Carbon Dioxide Step One Electron Transport Chain Krebs Cycle Occurs in Grana (membrane Occurs in Mito. Matrix (fluid in the stacks in chloroplasts) mitochondria) Uses/splits water Uses glucose (as pyruvate after glycolysis) Makes oxygen Makes carbon dioxide Step Two Calvin Cycle Electron Transport Chain Occurs in Stroma (fluid in the Occurs in Inner membranes of the chloroplasts) mitochondria Uses carbon dioxide Uses oxygen Makes glucose Makes water  O2 is Unavailable: Anaerobic Respiration In the absence of oxygen, a cell will go through anaerobic respiration and a process called fermentation. There are two main types of fermentation: – Lactic acid fermentation – Alcohol fermentation  Lactic Acid Fermentation Occurs in some bacteria and animal cells (like your muscles) Pyruvate from glycolysis is converted into lactic acid and 2 ATP  Alcohol Fermentation Occurs in yeast when oxygen is not available Pyruvate from glycolysis is broken down into alcohol, CO2, and 2 ATP  Total ATP Produced: Aerobic Respiration = 36-38 ATP – 2 ATP from Glycolysis – 2 ATP from Krebs Cycle – 34 ATP from Electron Transport Chain Anaerobic Respiration = 2-4 ATP  Photosynthesis vs. Cellular Respiration Photosynthesis Cellular Respiration Light energy CO2 C6H12O6 CO2 H 2O O2 H 2O ATP energy