Cellular Respiration

Cellular Respiration

“The Powerhouse” Image from: http://micro.magnet.fsu.edu/cells/mitochondria/mitochondria.html

Aerobic Cellular Respiration extracts energy from food in the presence of oxygen energy is used to synthesize ATP from ADP and Pi eukaryotes & prokaryotes that are obligate aerobes undergo Cellular respiration

Image from: http://factfictionfancy. wordpress

Aerobic Cellular Respiration 4 stages: Glycolysis Pyruvate oxidation (Transition stage) Citric acid cycle Electron transport Chain & oxidative phosphorylation

6 Carbons Glucose sugar Electron Transport Chain 32 ATP 6O2 6H2O C Pyruvate oxidation CO2 2 Citric Acid Cycle 2 ATP CO2 C 4 C 2 ATP Glycolysis C

1. Glycolysis takes place in cytoplasm enzymes break down one molecule of glucose into two molecules of pyruvate some ATP and NADH are produced

2. Pyruvate Oxidation (transition stage) occurs in the mitochondria pyruvate is transported (via carrier protein) into mitochondria and is oxidized, forming acetyl-CoA CO2 and NADH are produced

3. Citric Acid (Krebs) Cycle takes place in mitochondria acetyl-CoA enters a cycle and is completely oxidized to CO2 ATP, NADH and FADH2 are produced

4. Electron Transport… takes place in mitochondria the NADH and FADH2 from the first 3 stages are oxidized H2O and a large amount of ATP is produced (32-34)

ATP can be produced in two ways: 1. Substrate-level phosphorylation - catalyzed by a kinase - phosphate is transferred directly from a substrate (Image from: http://www.bio.miami.edu/~cmallery/150/makeatp/SLP.jpg

2. Oxidative phosphorylation catalyzed by ATP synthase process uses energy transferred indirectly from a series of redox reactions (Image from: http://www.sparknotes.com/biology/cellrespiration/oxidativephosphorylation/section3.rhtml)

What if there is no O2? many organisms can extract energy from food without using oxygen using anaerobic respiration and fermentation much lower amount of energy release in anaerobic pathways

Anaerobic Respiration We know what obligate aerobes are… What about… obligate anaerobes? facultative anaerobes? Obligate anaerobes - bacteria that cause botulism, tetanus, protist Trichonympha Facultative anaerobes - yeast, E. coli bacteria that live in our gut

Classwork/Homework Read 4.1 1-7 pg 171 Review notes 20