CELLULAR RESPIRATION
LEARNING OBJECTIVES 1. Describe the general flow of energy and food in living cells 2. Describe the organization of the mitochondria 3. Explain the main purpose and events of aerobic respiration 4. Compare aerobic respiration with alternative ways of generating energy in terms of mechanism and output 5. Discuss the importance of aerobic and alternative mechanisms of respiration Campbell et al., ch 9
THE BARE NECESSITIES OF A CELL carbohydrates fats proteins ATP
ATP: THE CURRENCY OF LIFE +7.3kcal/mol
FLOW OF ENERGY AND MATTER ECOSYSTEM Light energy CO 2 + H 2 O Photosynthesis in chloroplasts Cellular respiration in mitochondria Organic molecules + O 2 ATP ATP powers most cellular work Heat energy
GUIDE QUESTIONS Why is photosynthesis important to cells? respiration? Where does photosynthesis specifically occur? respiration? How are photosynthesis and respiration linked to each other? Can photosynthesis and respiration occur simultaneously in plant cells? Which type of plant cells undergo photosynthesis? Which type of plant cells undergo respiration? If animal cells do not perform photosynthesis, how do they obtain food?
MITOCHONDRIA https://micro.magnet.fsu.edu/cells/mitochondria/mitochondria.html
AEROBIC RESPIRATION food carbohydrates, lipids, proteins C 6 H 12 O 6 + 6O 2 à 6CO 2 + 6H 2 O + energy heat used to drive ATP formation
KEY PLAYERS glucose ATP electron electron carrier (NADH, FADH 2 ) electron acceptor (O 2 )
STAGES OF AEROBIC RESPIRATION cytosol intermembrane space 2NADH 2NADH or 2 FADH 2 2NADH glucose 2 pyruvate 2 acetyl-coa 6NADH + 2 FADH 2 ELECTRON TRANSPORT CHAIN e - O 2 2ATP 2CO 2 4CO2 2ATP H 2 O 26 or 28 ATP GLYCOLYSIS PYRUVATE OXIDATION CITRIC ACID CYCLE H+
AEROBIC RESPIRATION NADH glucose 2 pyruvate NADH NADH, FAHD 2 e - O 2 ATP ATP ATP GLYCOLYSIS CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN
GUIDE QUESTIONS What is responsible for the massive energy production in aerobic respiration? Why does the cell bother with glycolysis and citric acid cycle if they produce only minimal amounts of energy?
OTHER WAYS TO GENERATE ENERGY Anaerobic Respiration glycolysis citric acid cycle ETC final e- acceptor is not O 2 other molecules (SO 4-2, NO 3-, Fe +3 ) O 2
AEROBIC RESPIRATION NADH glucose 2 pyruvate e - O 2 ATP ATP ATP GLYCOLYSIS CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN
ANAEROBIC RESPIRATION NADH glucose 2 pyruvate e - SO 4-2, NO 3-, Fe +3 ATP ATP ATP GLYCOLYSIS CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN
LACTIC ACID FERMENTATION NADH e - glucose 2 pyruvate e - O 2 ATP lactic acid ATP ATP GLYCOLYSIS CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN
ALCOHOL FERMENTATION NADH e - ethanol acetylaldehyde glucose 2 pyruvate e - O 2 ATP ATP ATP GLYCOLYSIS CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN
GUIDE QUESTIONS What s the main difference between aerobic and anaerobic respiration? What is the implication of this? What happens to the electrons during lactic acid and alcohol fermentation? What is the implication of this?
FERMENTATION Glucose http://objetoseducacionais2.mec.gov.br/handle/mec/3433 Microbes in whisky fermentation, MBstained=dying cells (Priest 2004)
GUIDE QUESTIONS Why do muscles revert to fermentation during vigorous exercise? Explain the curve of the yeast vs the glucose curve during whisky fermentation. Explain the lactic acid bacteria curve vs the lactic acid curve during whisky fermentation. Explain the yeast vs lactic acid bacteria curve during whisky fermentation. Explain the lactic acid bacteria curve vs the glucose curve during whisky fermentation. If aerobic respiration is the most efficient way to generate energy, why do some cells prefer to use alternative but less efficient strategies for respiration?