CH 9 Cell Respiration Process that releases E from the food we eat E in food measured in calories— amount of E needed to raise the T° of 1 gm of water 1 degree C Calorie on food label= 1000 calories Because of the way atoms are bonded, different foods have different amounts of E 1 gm of Protein or CH2O= 4 calories, 1gm of fat= 9 calories Broken down into 3 separate processes

CH 9 Cell Respiration Glycolysis—anaerobic process that takes place 1st in the cytosol Each glucose (C6H12O6) can be converted to 2 pyruvate molecules (3 C each) and a small amount of ATP (adenosine triphosphate) 4 electrons are passed to NAD+ (nicotinamide adenine dinucleotide) turning it into NADH These high E electrons can be used to make even more ATP in the next process—the Krebs Cycle This starts when the pyruvate goes into the matrix (inside fluid) of the mitochondrion

In the presence of O2 (aerobic) pyruvate is used to produce large amounts of ATP –this is called the Kreb’s Cycle or sometimes called the Citric Acid Cycle Pyruvate is broken down into CO2 and a 2 C molecule This 2 C molecule joins a 4 C molecule to make citric acid Citric acid is broken down to the 4 C molecule, releasing more CO2 and more high energy electrons are picked up by NAD+ making more NADH Steps 2 and 3 continue over and over again (CYCLE) All these high energy electrons are then used in the last stage of cell respiration—the Electron Transport Chain

Electron Transport Chain Electron carriers pass on those high energy electrons to the electron transport chain They are used to change ADP (adenosine diphosphate) into ATP—lots of them!

C6H12O6 + 6O2→ 6CO2 + 6H2O + 36 ATP In plant cells the CO2 and H2O then do what? In animal cells the CO2 is a waste product— what happens to it?

Cell Respiration w/o O2, pyruvate converts to lactic acid (soreness in muscle cells) Or ethyl alcohol in yeast cells: fermentation CO2 made during fermentation is what causes bread to rise and gives alcoholic beverages their bubbles

Cell Respiration—all stages