Respiration is the process by which cells release energy from glucose or other organic molecules It is categorized based on the presence or absence of oxygen into two main types Aerobic Respiration and Anaerobic Respiration Definition A type of respiration that occurs in the presence of oxygen Complete breakdown of glucose into carbon dioxide and water Large amounts of energy are released approximately 38 ATP molecules per glucose molecule o Occurs in most plants animals and some microorganisms EQUATION Types of Respiration 1 Aerobic Respiration Key Features o o Steps o Glycolysis Occurs in the cytoplasm Glucose is broken into two molecules of pyruvate producing 2 ATP o Krebs Cycle Occurs in the mitochondria Pyruvate is further oxidized releasing carbon dioxide o Electron Transport Chain ETC Occurs in the mitochondrial membrane Produces the majority of ATP through oxidative phosphorylation 2 Anaerobic Respiration Definition A type of respiration that occurs in the absence of oxygen Key Features o o Incomplete breakdown of glucose Produces less energy 2 ATP molecules per glucose molecule o Occurs in some microorganisms muscle cells during vigorous exercise and in certain plants under low oxygen conditions Equation in Animals C6H12O6 2C3H6O3 Energy ATP C 6H 12 O 6 rightarrow 2C 3H 6O 3 Energy ATP C6H12O6 2C3H6O3 Energy ATP Glucose is converted into lactic acid Equation in Yeast Alcoholic Fermentation C6H12O6 2C2H5OH 2CO2 Energy ATP C 6H 12 O 6 rightarrow 2C 2H 5OH 2CO 2 Energy ATP C6H12O6 2C2H5OH 2CO2 Energy ATP Glucose is converted into ethanol and carbon dioxide Comparison Between Aerobic and Anaerobic Respiration Aspect Aerobic Respiration Anaerobic Respiration Oxygen Requirement Requires oxygen Does not require oxygen Energy Production Produces more energy 38 ATP Produces less energy 2 ATP End Products Carbon dioxide and water Lactic acid in animals ethanol and CO in yeast Occurrence Most plants animals and aerobic bacteria Some bacteria yeast and muscle cells during exercise Significance of Respiration Provides energy required for various cellular processes such as growth reproduction and repair Enables organisms to maintain life functions and perform activities Applications of Anaerobic Respiration In Humans During strenuous activities like running anaerobic respiration in muscles produces lactic acid causing muscle cramps In Industry Anaerobic respiration by yeast is used in baking to produce CO for dough rising and brewing for ethanol production