BIOLOGY Cellular Respiration

Overview of photosynthesis and respiration SUN RADIANT ENERGY CELL ACTIVITIES PHOTOSYNTHESIS RESPIRATION GLUCOSE ATP(ENERGY)

EQUATION FOR PHOTOSYNTHESIS WATER OXYGEN 6CO2 + 6H2O + ENERGY C6H12O6 + 6O2 CARBON DIOXIDE GLUCOSE

EQUATION FOR RESPIRATION CARBON DIOXIDE ATP GLUCOSE C6H12O6 + 6O2 6CO2 + 6H2O + ENERGY OXYGEN WATER

RESPIRATION CYTOPLASMGLYCOLOSIS HAPPENS HERE! CO2 IS RELEASED PROTEINS CARBO’S (SUGARS) FATS (LIPIDS) GLUCOSE C6H12O6 AMINO ACIDS MAKES 2 ATPS GLYCOLOSIS IN CYTOPLASM NO OXYGEN! ATP TOTALS GLYCOLOSIS=2 RESPIRATION=34 BOTH=36! PYRUVIC ACID CO2 IS RELEASED ACETYL-CoA O2 ENTERS HERE KREBS CYCLE AND ELECTRON TANSPORT MAKES 34 ATPS MITOCHONDRIARESPIRATION HAPPENS IN THIS ORGANELLE!

Cellular Respiration A cellular process that requires oxygen and gives off carbon dioxide. Carbohydrates, fats, and proteins can be used as energy sources. Most often involves breaking down glucose to make CO2, H2O, and ATP. Catabolism breaks down molecules that can also be used for anabolism to build other compounds.

Glycolysis It was discovered by Gustav Embden , Otto Meyerhof ,J. Parnas therefore it is also called as EMP Pathway

Glycolysis Energy within a glucose molecule is released slowly so that ATP can be produced gradually. 2 ATP used to activate glucose that splits into PGAL. Substrate-Level Phosphorylation Oxidation of PGAL results in four high-energy phosphate groups, making four ATP. NAD+ and FAD are oxidation-reduction enzymes active during cellular respiration.

Substrate-level Phosphorylation

Inside the Mitochondria End product of glycolysis, pyruvate, enters the mitochondria, where it is oxidized to carbon dioxide during the transition reaction and citric acid cycle.

Conversion of pyruvate to acetyl CoA, the junction between glycolysis and the Citric Acid cycle

Transition Reaction Connects glycolysis to the citric acid cycle.

Citric Acid Cycle Originally called Krebs cycle.

A summary of the Krebs cycle For each molecule of Acetyl CoA, the Citric Acid Cycle produces 2 ATP and 2 CO2 molecules. Has 8 steps with 8 different enzymes.

Electron Transport System As electrons pass down the electron transport system, energy is captured and ATP is produced. Oxidative phosphorylation refers to the production of ATP as a result of energy released by the electron transport system. The total of 32-34 ATP produced by ETS is calculated by allowing 3 ATP per NADH and 2 ATP per FADH2 that enter the ETS.

NAD+ as an electron shuttle

Figure 9.5 An introduction to electron transport chains

Chemiosmosis couples the electron transport chain to ATP synthesis Yellow arrow = electron flow Red arrow = proton flow to form ATP

Figure 9.14 ATP synthase, a molecular mill

Cellular Respiration Summary

Control of Cellular Respiration The important switch in the control of respiration is the enzyme phosphofructokinase. This enzyme catalyzes step 3 of glycolysis. Phosphofructokinase is inhibited by ATP and stimulated by ADP or AMP. It is also inhibited by citric acid. This synchronizes the rates of glycolysis and the Krebs Cycle.

Fermentation Glycolysis followed by reduction of pyruvate by NADH to either lactate or alcohol and carbon dioxide. Anaerobic pathway. Can provide rapid burst of ATP. Lactic Acid Fermentation is common in muscle cells.

Fermentation Alcohol--yeast produce wine and beer and cause bread to rise. Lactic Acid—bacteria produce yogurt, sauerkraut, cheese. Also in muscle cells when working anaerobically.

Comparison of Cellular Respiration versus Fermentation One mole of glucose yields 686 kcal in a colorimeter. Cellular respiration has a yield of about 263 kcal. 263/686 = 38% of available energy is used. What happened to the rest? Fermentation yields only 2 ATP or about 15/686 or 2% of available energy.

Figure 9.2 A review of how ATP drives cellular work