THE CELLULAR RESPIRATION SAGA II: THE CITRIC ACID CYCLE & OXIDATIVE PHOSPHORYLATION

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1 THE CELLULAR RESPIRATION SAGA II: THE CITRIC ACID CYCLE & OXIDATIVE PHOSPHORYLATION PLAYERS OF CELLULAR RESPIRATION NAD+ is a coenzyme that is reduced to using electrons Becomes reduced + H NAD + H + H + + (carries) electrons) 1

2 PLAYERS OF CELLULAR RESPIRATION Electron transport chains NAD + Energy released and available for making 1 O H O H + 3 Figure Electrons carried by Glycolysis Glucose Pyruvate CYTOSOL MITOCHONDRION

3 GLYCOLYSIS Takes place in cytoplasm of all living organisms 4 s made (synthesized) s invested = net s via substrate level Pyruvate molecules synthesized from 1 glucose No Oxygen required! NAD + s reduced to s = 4 electrons stolen 5 CELLULAR RESPIRATION Glycolysis, fermentation and pyruvate oxidation 3

4 PYRUVATE OXIDATION Cleans up the two pyruvates for the citric acid cycle Start with 3 Carbons End with Carbons and a coenzyme (Acetyl ) Produce + CO NAD + + H + Pyruvate 1 CO 3 Coenzyme A Acetyl coenzyme A 7 AEROBIC RESPIRATION ROAD MAP Starts with glucose, end with + CO + water + heat CYTOSOL MITOCHONDRION Glycolysis Glucose Pyruvate Pyruvate Oxidation Acetyl Citric Acid Cycle + by substrate-level CO + by substrate-level 4

5 CITRIC ACID OR KREBS CYCLE Operation: Capture Electrons! 6 steps OXYGEN REQUIRED No energy investment necessary finish start 9 CITRIC ACID OR KREBS CYCLE Operation: Capture Electrons Step 1: Get rid of coenzyme and bond with 4 C molecule to make 6C molecule Acetyl carbons enter cycle Oxaloacetate 1 Citrate 10 5

6 CITRIC ACID OR KREBS CYCLE Operation: Capture Electrons Step : Oxidize 6 C molecule to give CO is released Left with 5 C molecule Citrate NAD + +H + CO leaves cycle 11 CITRIC ACID OR KREBS CYCLE Operation: Capture Electrons Step 3: Make an by substrate level CO is released More is made Left with 4 C molecule CO leaves cycle 3 NAD + ADP + P +H + 1 6

7 CITRIC ACID OR KREBS CYCLE Operation: Capture Electrons Steps 4 6: More CO, Release FADH Add water to re make 4C molecule we started with Finish start 13 KREBS CYCLE Operation: Capture Electrons Lots of redox reactions harvest electrons Acetyl Starts and ends with oxaloacetate (4C molecule) Citric Acid Cycle CO FADH 3 NAD + FAD 3 +3 H + ADP + P 7

8 KREBS OR CITRIC ACID CYCLE Takes place in mitochondria s synthesized via substrate level Acetyl reacts with oxaloacetate and cycle renews oxaloacetate Oxygen required! Co given off 4 NAD + s reduced to s FADs reduced to FADH s = 1 electrons banked FADH FADH 15 AEROBIC RESPIRATION Electrons carried by FADH Glycolysis Glucose Pyruvate Pyruvate Oxidation Citric Acid Cycle Oxidative Phosphorylation (Electron transport and chemiosmosis) CYTOSOL MITOCHONDRION Substrate-level Substrate-level Oxidative 8

9 OXIDATIVE PHOSPHORYLATION Operation: Make OXIDATIVE PHOSPHORYLATION Chemiosmosis generates energy to phosphorylate Gradient of H+ ions create potential energy on the outside of the inner mitochondrial membrane (remember it has ) Synthase acts like a turbine or rotor 9

10 CHEMIOSMOSIS The process of making from a Concentration gradient INTERMEMBRANE SPACE Rotor H + The energy of H+ rushing in provides the energy to phosphorylate ADP to Oxidative Phosphorylation rather than substratelevel ADP + P AEROBIC RESPIRATION Oxidation of 1 glucose molecule CYTOSOL MITOCHONDRION 6 + FADH Glycolysis Glucose Pyruvate Pyruvate Oxidation Acetyl Citric Acid Cycle Oxidative Phosphorylation (electron transport and chemiosmosis) O H O Maximum per glucose: + CO + + about 8 About 3 by substrate-level by substrate-level by oxidative 10

11 AEROBIC RESPIRATION MANY steps result in products necessary to live C 6 H 1 O 6 6 O 6 CO 6 H O Heat *Glucose Oxygen Carbon dioxide Water *Glucose is the preferred molecule for respiration, but we can use 1 other types also FROM OTHER SOURCES Food Carbohydrates Fats Proteins Sugars Glycerol Fatty acids Amino acids Amino groups Glucose G3P Pyruvate Glycolysis Acetyl Citric Acid Cycle Oxidative Phosphorylation 11

12 THE BIGGER PICTURE Sunlight energy ECOSYSTEM Photosynthesis in chloroplasts CO Organic +H O + O Cellular molecules respiration in mitochondria powers most cellular work Heat energy REQUIRED VIDEO & READING Required Video! The Cellular Respiration Song Video links on website: Biosbcc.net/harrer 1

13 TODAY s CHECK IN (3pts) Open Notebook & NOTHING ELSE! **First try with no notes! 1. Draw a diagram showing the pathways of cellular respiration. Include glycolysis, pyruvate oxidation, the krebs cycle, oxidative and fermentation (pts).. Rate your understanding. Be honest. (1pt) A) Easy money, I totally get it! B) I get the idea but the details are still a tad fuzzy. C) This was hard, I should probably stop by for office hours to clarify. 13