Notes: Cellular Respiration

Cellular Respiration Cellular respiration makes ATP by breaking down sugars and other carbon- based molecules aerobic (requires oxygen) Takes place in mitochondria

Cellular Respiration Overall Equation: C6H12O6 + 6O2 → →→→6CO2 + 6H2O + ATP How is this different from photosynthesis?

Glycolysis Means “glucose breaking” C6H12O6 (glucose) broken into two 3-carbon molecules of pyruvic acid Produces 2 molecules of ATP

Glycolysis Occurs in the cytoplasm next to the mitochondria Anaerobic process (does not require oxygen) Reactant: Glucose Product: 2 ATP and Pyruvic Acid This will enter the mitochondria for further processing

Aerobic Respiration Aerobic Respiration takes place in two main stages Requires oxygen (aerobic) Occurs in the mitochondria

Aerobic Respiration Step 1: Kreb’s Cycle Takes place in interior space of mitochondria called the matrix (liquid inside mitochondria) Pyruvic acid made in glycolysis are broken down further

Aerobic Respiration Step 1: Kreb’s Cycle This produces carbon dioxide (CO2) and ATP. ATP is transferred to 2nd step of aerobic respiration. Reactants: Pyruvic Acid Products: CO2 and 2 ATP

Aerobic Respiration Step 2: Electron Transport Chain Takes place in inner membrane (cristae) ATP is transferred to electron transport chain from Kreb’s Cycle

Aerobic Respiration Step 2: Electron Transport Chain Oxygen enters process and picks up electrons and hydrogen to make H2O (water) Many enzymes required for process 34 ATP produced for a total of 36 including glycolysis Reactants: ATP and O2 Products: H2O and 34ATP

Overall Equation C6H12O6 + 6O2 → →→→6CO2 + 6H2O + ATP

Fermentation Anaerobic process Fermentation allows glycolysis to continue making ATP when oxygen is unavailable

Fermentation Glycolysis makes 2 ATP Better to make two than none!

Fermentation Types Lactic Acid Fermentation– occurs in muscle cells 2. Alcoholic Fermentation

Energy and Exercise Short Term Energy Cells contain only enough ATP for a few seconds of intense activity Then cells rely on lactic acid fermentation (can supply for about 90 seconds) Lactic acid build-up causes burning in muscles. Only way to get rid of lactic acid is chemical pathway that requires oxygen (why you breathe heavy after heavy exercise.)

Energy and Exercise Long Term Energy Cellular respiration only way to produce continuous supply of ATP Energy stored in muscles and other tissue in form of carbohydrate glycogen Enough glycogen for about 15 to 20 min When glycogen used up, body breaks down other stored molecules including fats, for energy.