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Chapter 9. Respiration. The route from food to energy. The route from food to energy. Glycolysis. Breaks glucose down into 2 pyruvic acid molecules Occurs in cytoplasm. Glycolysis. 2 ATP invested 4 ATP generated 2 “net” ATP gained Fast process! But… runs out of NAD+ rather quickly
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Chapter 9 Respiration
Glycolysis • Breaks glucose down into 2 pyruvic acid molecules • Occurs in cytoplasm
Glycolysis • 2 ATP invested • 4 ATP generated • 2 “net” ATP gained • Fast process! • But… runs out of NAD+ rather quickly • Process can’t go further
Fermentation • Occurs after glycolysis • Does not require oxygen • Anaerobic • Switches NADH back into NAD+ • Allows glycolysis to continue
Fermentation • Two flavors • Alcoholic fermentation • Lactic acid fermentation
Alcoholic fermentation • Done by yeast and other microbes • Formula • Makes bread, wine, and other food products
Lactic Acid Fermentation • Done in our muscles! • And other cells too • Formula
Lactic Acid Fermentation • Done in muscles during rapid exercise • Lactic acid causes the pH to drop in your cells • Makes you feel a burn, stop until you can get O2 again • Makes cheese, yogurt, buttermilk, sour cream and other products
Aerobic Respiration • After glycolysis • Only in eukaryotes • Require oxygen—aerobic • NOT THE SAME AS REGULAR RESPIRATION!
Where does aerobic respiration happen? • In the mitochondria! • Mitochondria are organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use
2 Main steps of Aerobic Respiration • Kreb’s cycle • Pyruvic acid is broken down into CO2 in a series of energy-extracting reactions • Also known as the Citric Acid Cycle • 2 ATP are generated
2 Main steps of Aerobic Respiration • Electron Transport Chain • Uses high energy electrons from the Kreb’s cycle to convert ADP into ATP • 32 ATP are produced
Comparing Aerobic Respiration to glycolysis and Fermentation • Glycolysis 2 ATP • Fermentation 0 ATP • Kreb’s Cycle 2 ATP • Electron transport 32 ATP • Anaerobic _________ • Aerobic ___________ AEROBIC RESPIRATION is 18 TIMES MORE EFFICIENT!
Where to go for energy? • Instant energy—glycolysis LESS ATP • Fast energy—fermentation • Slow energy—cellular respiration MOST ATP