Ms. Napolitano & Mrs. Haas CP Biology Cellular Respiration Ms. Napolitano & Mrs. Haas CP Biology

Recall: The photosynthesis equation is 6CO2 + 6H2O + light  6O2 + C6H12O6

Food Food – source of raw material for the cells of the body Energy source calorie – amount of energy needed to raise 1 gram of water 1 degree Celsius Calorie = kilocalorie = 1000 calories

Cellular Respiration Cellular respiration – the process that releases energy by breaking down glucose & other food molecules in the presence of oxygen The equation for cellular respiration is: 6O2 + C6H12O6  6CO2 + 6H2O + Energy Look familiar?!?!?!?! 

3 Parts of Cellular Respiration: Glycolysis Cytoplasm Krebs cycle (AKA citric acid cycle) Mitochondrial matrix Electron transport chain Inner mitochondrial matrix

PART I Glycolysis

Glycolysis Glycolysis – process in which one molecule of glucose is broken in half Produces 2 molecules of pyruvic acid = 3C compound Anaerobic - does not require O2

ATP & NADPH Production The cell needs to input some energy before more can be produced 2 ATP used up, 4 ATP made = 2 ATP net gain High-energy electrons are carried by NAD+ Makes NADH Similar to NADP+ in photosynthesis Overall glycolysis equation: glucose  2 pyruvic acid + 2 ATP + 2 NADH

PART II The Krebs Cycle

The Krebs Cycle Recall: 2 pyruvic acid molecules were made during glycolysis Krebs cycle – pyruvic acid is broken down into CO2

Steps of the Krebs Cycle: 1C from pyruvic acid becomes CO2 Other 2C’s joined to a coenzyme to make acetyl-CoA Acetyl group (2C) is converted to citric acid (4C) 6C compound Citric acid becomes 4C again C’s become CO2 ADP  ATP NAD+  NADH FAD  FADH2 High-energy electron carriers

Final Products of the Krebs Cycle: 8 NADH 2 FADH2 2 ATP 6 CO2

The Electron Transport Chain PART III The Electron Transport Chain

The Electron Transport Chain The electron transport chain – uses high-energy electrons from the Krebs cycle to convert ADP into ATP

Product: H2O e- are passed from one protein to the next Enzyme at the end combines e- with H+ and O2 to form H2O

Product: ATP When 2e- pass through ETC, energy transports H+ across the membrane ATP synthase pumps H+ to the other side of the membrane via facilitated diffusion ATP synthase rotates like a turbine, making ADP + P  ATP

Other Stuff!

Totals Glycolysis = 2 ATP (net) Krebs cycle + ETC = ~36 ATP Total = ~38 ATP molecules from 1 glucose molecule!

Fermentation Fermentation – process by which ATP is made in the absence of O2 AKA anaerobic Goes through glycolysis, then picks a different pathway Alcoholic fermentation Alcohol & CO2 is made as wastes Made by yeast - causes bread to rise Lactic acid fermentation Lactic acid is made as a waste Causes muscle soreness or helps make dairy products

Energy & Exercise Quick energy Long-term energy Only enough ATP in muscles for ~50m sprint (few seconds) Lactic acid fermentation – ATP made for ~200-300m sprint (~90s) Lactic acid removal requires extra O2 Long-term energy Cell respiration is the only way to make ATP for the long-term Pace yourself! Energy stored in muscles as glycogen Stored glycogen - ~15-20 min of activity, then other energy forms get broken down (ex. fats – weight control!)