Chapter 9 Cellular Respiration

9-1 Chemical Pathways Chemical Energy & Food 1 gram of sugar (glucose) has 3811 calories of heat energy calorie: Amount of heat energy needed to raise the temperature of 1g of water 10C Calorie (kilocalorie) used in food labeling 1000 calories = 1 Calorie Energy is gradually released from glucose and other food molecules when it is converted into ATP.

Overall View of Cellular Respiration 9-1 Chemical Pathways Overall View of Cellular Respiration Chemical Formula C6H12O6 + 6O2 6CO2 + 6H2O + Energy (ATP)

9-1 Chemical Pathways Glycolysis Beginning process in the conversion of food into ATP. Occurs the Cytoplasm of the cell Requires 2 ATP’s of activation energy Converts glucose one C6H12O6 into two Pyruvic acid molecules 4 high energy electrons are passed to the carrier molecule NAD+ to form NADH 4 molecules of ATP are released

To the electron transport chain Glycolysis Section 9-1 Glucose 2 Pyruvic acid To the electron transport chain Go to Section:

9-1 Chemical Pathways Fermentation Release of energy from food molecules in the absence of oxygen (Anaerobic Respiration) 2 Fermentation Pathways Alcoholic Fermentation – Plant cells Pyruvic Acid + NADH Alcohol + CO2 + NAD+ Lactic Acid Fermentation – Animal cells Pyruvic Acid + NADH Lactic Acid + NAD+

Lactic Acid Fermentation Section 9-1 Lactic Acid Fermentation Lactic acid Glucose Pyruvic acid Go to Section:

9-2 Krebs Cycle & the ETC Aerobic Respiration Chemical pathway taken when Oxygen is present. Occurs in the Mitochondria Releases large amount of ATP from the continued breakdown of glucose.

9-2 Krebs Cycle & the ETC The Krebs Cycle Pyruvic Acid from glycolysis is used to make CO2, NADH, ATP & FADH2 Krebs cycle occurs in the mitochondria.

9-2 Krebs Cycle & the ETC The Krebs Cycle Steps of Krebs Cycle Citric Acid Production Pyruvic Acid enters mitochondria – Carbon is removed forming CO2 Electrons are removed when NAD+ is converted into NADH Coenzyme A joins 2-carbon molecule forming Acetyl- CoA Acetyl-CoA then adds the 2-carbon acetyl group to a 4- carbon compound forming Citric Acid.

9-2 Krebs Cycle & the ETC The Krebs Cycle Steps of Krebs Cycle Energy Extraction Citric Acids is broken down into a 5-carbon compound then a 4-carbon compound. Along the way 2 CO2 molecules are released Electrons join NAD+ and FAD to form NADH & FADH2 One molecule of ATP is generated Energy tally from one Pyruvic Acid molecule 4 NADH 1 FADH2 1 ATP

Figure 9–6 The Krebs Cycle Section 9-2 Citric Acid Production Mitochondrion Go to Section:

Electron Transport Chain (ETC) 9-2 Krebs Cycle & the ETC Electron Transport Chain (ETC) ETC uses high energy electrons from Krebs Cycle (NADH & FADH2) to convert ADP into ATP

Electron Transport Chain (ETC) 9-2 Krebs Cycle & the ETC Electron Transport Chain (ETC) Steps of ETC Electron Transport High energy electrons from NADH & FADH2 are passed along the ETC which is a series of proteins in the inner membrane of the Mitochondria Oxygen acts as the final electron acceptor getting rid of the waste of cellular respiration (low energy electrons and hydrogen ions) forms H2O

Electron Transport Chain (ETC) 9-2 Krebs Cycle & the ETC Electron Transport Chain (ETC) Steps of ETC Hydrogen Ion Movement As high energy electrons move down the ETC hydrogen ions are pumped into the intermembrane (Active Transport) Intermembrane becomes positively charged

Electron Transport Chain (ETC) 9-2 Krebs Cycle & the ETC Electron Transport Chain (ETC) Steps of ETC ATP Production As hydrogen ions escape through ATP synthase ADP is convert to ATP Each pair of electrons can converted 3 ADP into 3 ATP

Figure 9–7 Electron Transport Chain Section 9-2 Electron Transport Hydrogen Ion Movement Channel Mitochondrion Intermembrane Space ATP synthase Inner Membrane Matrix ATP Production Go to Section:

9-2 Krebs Cycle & the ETC Total ATP Net Gain 36 ATP Energy Totals Glycolysis (2 input 4 output) +2 Krebs Cycle +2 ETC (2 input 34 output) +32 Total ATP Net Gain 36

9-2 Krebs Cycle & the ETC Energy & Exercise Short Term – 90 Seconds or Less Lactic Acid Fermentation Long Term 15 – 20 minutes of stored glycogen after that the cells breakdown other sources of energy in the following order Complex Carbohydrates Lipids

Comparing Photosynthesis to Cellular Respiration 9-2 Krebs Cycle & the ETC Comparing Photosynthesis to Cellular Respiration Photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2 Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + Energy (ATP) Light Chlorophyll