Cellular Respiration

1. Cellular Respiration Chapter 7

2. Cellular Respiration – complex process in which cells make ATP by breaking down organic compounds – both autotrophs and heterotrophs go through this process to release energy – makes ATP, CO2 & H2O from organic compounds & O2 – products are reactants in photosynthesis C6H12O6 + 6O2ENZYMES 6CO2 + 6H2O + ATP Sugar + water carbon dioxide + water + energy

3. 2 Stages of Cellular Respiration Glycolysis – organic compounds converted into 3 carbon molecules of pyruvic acid; anaerobic process because it does not require oxygen Aerobic Respiration – if O2 is present in the surrounding environment, pyruvic acid is broken down & NADH is used to make large amount of ATP through this process

4. Glycolysis - Biological pathway

5. 2 stages Aerobic Respiration In Prokaryote Cells – occurs in cytosol In Eukaryote Cells – occurs in mitchondria, more specifically in the mitochondrial matrix (space inside inner membrane) Matrix contains enzymes that are needed to catalyze the reactions of the Krebs cycle Krebs Cycle – biochemical pathway breaks down acetyl CoA producing CO2, H atoms, & ATP; chemicals identified by Hans Krebs, a German biochemist Electron Transport Chain associated with chemiosmosis

6. Krebs Cycle consists of 5 Stages

7. Fermentation - Combination of glycolysis & anaerobic pathways that pyruvic acid can enter if there is no oxygen present • Lactic Acid Fermentation – microorganisms play essential roles in the manufacture of many dairy products • Examples: cheese, buttermilk, yogurt, sour cream, and other dairy products • -occurs in muscles during strenuous exercise, such as sprinting • muscles use up O2 more rapidly than it can be delivered to them

8. 2. Alcoholic Fermentation – used by some plant cells and unicellular organisms • Example: Yeast (a fungi which means that it cannot produce its own food) • -converts pyruvic acid into ethyl alcohol • - basis of wine and beer industry • table wines – CO2 escapes • sparkling wines – CO2 retained, “carbonating” beverage • bread rising is caused by CO2 bubbling, alcohol evaporates during baking

9. Summary of Cellular Respiration Glycolysis – glucose is converted into pyruvic acid, producing a small amount of ATP & NADH Aerobic Respiration – pyruvic acid converted into CO2 & H2O in the presence of O2, producing a large amount of ATP • Molecules that are formed at different steps in glycolysis and Krebs cycle are used to make cells that make certain compounds, which are missing in food.