Cellular Respiration, Lecture notes of Cell Biology

Download Cellular Respiration and more Lecture notes Cell Biology in PDF only on Docsity! Energy and Metabolism Energy and Metabolism Our cells perform exergonic reactions when … Th ey m ak e n ew ha ir Th ey m ak e n ew sk in Th ey bu rn fat s 1 an d 2 25% 25%25%25% 1. They make new hair 2. They make new skin 3. They burn fats 4. 1 and 2 Our cells perform endergonic reactions when … Th ey m ak e n ew ha ir Th ey m ak e n ew sk in Th ey bu rn fat s 1 an d 2 25% 25%25%25% 1. They make new hair 2. They make new skin 3. They burn fats 4. 1 and 2 Energy and Metabolism Biosynthetic and Degradative Pathways • Biosynthetic Pathway: Anabolism • Degradative Pathway: Catabolism The Flow of Energy or How Organisms Relate • Photoautotrophs synthesize high energy organic molecules during photosynthesis • Both photoautotrophs and heterotrophs use such organic molecules to obtain energy (ATP) through cellular respiration for fueling cellular work Participants in Metabolic Pathways • Substrate: • Intermediate Product(s): • End Product(s): • Enzymes: • Energy Carriers: Photosynthetic bacteria are autotrophs because they have the ability to produce their own high energy organic compounds (food). Do you agree? Yes No 50%50% 1. Yes 2. No Hydrolysis of ATP into ADP Energy and inorganic phosphate are released. What for? The ATP/ADP Cycle From Degradative Pathways For Synthetic Pathways Phosphorylation Energy Releasing Pathways Fermentation Fermentation (alcoholic and lactic): 2 ATP’s produced. www.schmohz.com/beerinfo1.html Energy Releasing Pathways Aerobic Respiration • Aerobic Respiration: approximately 36 ATP molecules produced • Aerobic organisms perform aerobic respiration Which one of the following is the most effective pathway for producing ATP? fer men tat ion an ae rob ic r es pir ati on ae rob ic r es pir ati on 33% 33%33% 1. fermentation 2. anaerobic respiration 3. aerobic respiration Depending on their oxygen needs, organisms are • Strictly Aerobic: require oxygen • Facultative Aerobic • Strictly Anaerobic: do not tolerate oxygen • Facultative Anaerobic Where does aerobic respiration occur? Mitochondrion Intermembrane space membrane in the ‘ mitochondrial matrix Mitochondrial DNA Steps of Aerobic Respiration: Glycolysis • All organisms (anaerobic and anaerobic) break down glucose trough the process of glycolysis, which occurs in the cell’s cytoplasm • Only aerobic organism process the products of glycolysis to obtain further amounts of ATP • Glucose is actively transported into the cell and phosphorylated (step 1), process that turns on glycolysis Steps of Aerobic Respiration: Glycolysis • 2 molecules of pyruvate are produced per molecule of glucose • A net of 2 ATP per molecule of glucose are produced in glycolysis Where is the pyruvate coming from? La cti c f erm en tat ion Alco ho lic fer men tat ion Aero bic re sp ira tio n All o f th e a bo ve 25% 25%25%25% 1. Lactic fermentation 2. Alcoholic fermentation 3. Aerobic respiration 4. All of the above Steps of Aerobic Respiration: Krebs Cycle • Per molecule of pyruvate, 1 ATP, 1 FADH2, 3 CO2, and 4 NADH are produced • NADH and FADH2 will initiate the last step of aerobic respiration, the electron transport phosphorylation system (ETPS). Steps of Aerobic Respiration: ETPS • ETPS consists of a series of proteins located in the inner mitochondrial membrane • NADH and FADH2 link glycolysis and the Krebs cycle to the machinery that produces large amounts of ATP • NADH and FADH2 turn on the ETPS. Electrons cascade down the chain from one protein to the next until they finally reach the molecule of oxygen, the final acceptor • As electrons cascade down, protons are released Steps of Aerobic Respiration: ETPS Aerobic Respiration: What does it produce? Electron shuttles ‘span membrane MITOCHONDRION CYTOSOL [ +2aTP +2 ATP +about32o0r34ATP | by substrate-level by substrate-level by oxidative phosphorylation, depending phosphorylation phosphorylation on which shuttle transports electrons : from NADH in cytosol F ~~ About Maximum per glucose: 36 or 36 ATP Plants need to burn sugars and fats to obtain ATP. Do you agree? Yes N o 50%50% 1. Yes 2. No