Chemical Energy From Food  Cellular respiration is a set of reactions that convert the energy of food into energy the cell can use: ATP (energy)  (Currency exchange in the cell) “Cellular respiration is the process that releases energy (ATP) by breaking down food molecules in the presence of oxygen”

Equation  Oxygen + glucose  Carbon dioxide + water + energy C 6 H 12 O 6 + O 2  CO 2 + H 2 O + ATP  Respiration takes place in the mitochondria OF ALL EUKARYOTES!  Plants, Animals, Fungi, etc

Overview of Cellular Respiration Food (glucose) Glycolysis Fermentation Krebs cycle No O 2 Yes O 2 Energy 2 ATP 36 ATP (Alcohol Fermentation or Lactic Acid Fermentation)

Two-step process  Step 1: Glycolysis  “splitting sugar”  The act of splitting glucose into smaller parts You get TWO molecules ofC 3 H 6 O 3  Universal metabolic process  Almost every living organism does this!

Then we decide do, we have O 2 or not?  Depending upon if oxygen is present, the pathway splits

If we DO have O 2 (Krebs cycle)  (Goes by both names)  Is an Aerobic process This means it requires oxygen! (“with air”)  MUCH more energy efficient  For every glucose we split, we get 36 ATP!

If we do NOT have O 2 Then we do a process called Fermentation  Anaerobic  (“an” = “without”)  (“aero” = “air”)  Not terribly energy efficient  For every glucose molecule we split, we only get 2 ATP   This does happen in humans, think about athletes! Latic acid build-up Lactic acid fermentation is also what causes sour cream, pickles, etc to taste sour Other one is Alcohol Fermentation Happens in yeast and is responsible for making alcohol and bread

Phot/Resp Differences Photosynthesis  Reactants:  CO 2 + H 2 O + light  Products  Glucose and oxygen  Cell that carries it out  Autotrophs  Organelle:  Chloroplast Respiration  Reactants:  Glucose + O 2  Products  CO 2, H 2 O, ATP  Cell that carries it out:  All eukaryotes  Organelle:  Mitochondria

The equations  Photosynthesis:  CO 2 + H 2 O + light  C 6 H 12 O 6 + O 2  Carbon dioxide + water + light  sugar + oxygen  Respiration is:  O 2 + C 6 H 12 O 6  CO 2 + H 2 O + energy  Oxygen + glucose  Carbon dioxide + water + energy