Energy Releasing Pathways (Cell Respiration) I. Introduction A. History 1. A. Lavoisier in the 1700’s can make wine without living organisms 2. F. Wohler and J. von Leibig supported this idea, but T. Schwann showed juice would not ferment without yeast. 3. In 1860 L. Pasteur proved ethanol amount proportional to the amount of yeast present

4. In 1897 the E. Buchner brothers steps of glycolysis key to fermentation 5. In the early 1900’s A. Szent-Gyorgyi designed Citric Acid Cycle, failed to show relationship to fermentation 6. H. Krebs in 1938 linked glycolysis to citric Acid Cycle via enzyme CoA Kreb’s Cycle

A. Overview Figure 9.6 II. Aerobic Respiration

a. Cytosol Figure 6.8Figure Where occurs? B. Glycolysis

a. Components: Figure Steps and Players ii. Splitting, i. Investment, & iii. Harvest

i. Investment 1. Kinase enzyme attaches a P from ATP to glucose (6C) making glucose-P Prevents glucose from moving back out of cell 3. Kinase enzyme attaches another P from second ATP to fructose-P, making P-fructose-P Generates a balanced molecule with a P at either end. 2. Isomerase rearranges glucose-P into fructose-P (6C) Prepares molecule to add another Phosphate ii. Splitting 1. Aldolase enzyme cuts molecule P-fructose-P into two 3C molecules G3P and Dihydroxyacetone-P 2. Dehydrogenase enzyme liberates H and NAD + steals the electrons from H This happens twice or once for each G3P 3. The hole left by the leaving H is backfilled by Pi and forms G1,3P This step balances the two G3P’s with a P on both ends How many NADH + H are formed per glucose?

iii. Harvest 1. Kinase enzyme directly transfers a P from G3P to ADP to make ATP by substrate level phosphorylation (SLP) How many times does this happen to make how many ATP’s? 2. Mutase enzyme rearranges G3P into G2P 3. Enolase enzyme rearranges G2P into PEP Prepares molecule for more harvest Prepares molecule for more harvest 4. Kinase enzyme directly transfers a P from PEP to ADP to make ATP by SLP Makes pyruvate out of each PEP

a. 2ATP are used by the cell. b. NADH + H  mitochondria and electron transport chain The next two outcomes only happen if oxygen is present in the cell. c. 2pyruvic acids are combined to CoA to go to the mitochondria and the Kreb’s cycle 3. Outcomes

a. Cytoplasm to Mitochondria Figure Where occurs? 2. Steps a. Dehydrogenase enzymes splits off a CO 2 from pyruvic acid which liberates electrons from H and given to NAD+ to make a 2C acetyl group b. Combine acetyl group to Co-enzyme A to be transported to the mitochondria How many times this happen? C. Transport

a. NADH + H  mitochondria and electron transport chain The next three outcomes only happen if oxygen is present in the cell. b. 2pyruvic acids combined to 2CoA go to the mitochondria and the Kreb’s cycle 3. Outcomes c. What is the fate of the CO 2 ?

a. Mitochondrial Matrix Figure Where occurs? D. Krebs Cycle

a. Divisions Figure Steps i. Destroying ii. Rearranging

i. Destroying 1. Citrate synthase combines acetic group to oxaloacetic acid to begin cycle 2. Dehydrogenase enzymes splits out CO 2 and liberates H to NAD+ How many CO 2 are liberated? 3. As H’s are removed then a Pi jumps on only to be removed to form ATP by SLP ii. Rearranging 1. Mutase and dehydrogenase enzymes reshape molecule to liberate more H’s to rebuild oxaloacetic acid 2. Liberates H and NAD + or FAD steals the electrons This happens twice for glucose or once for each acetic group.

a. ATP is used b. CO 2 diffuses into cytosol and is lost c. NADH + H and FADH 2 are sent to electron transport chain 3. Outcomes

a. Inner Mitochondrial Membrane Figure Where occurs? E. Electron Transport Chain

a. Divisions 2. Steps i. Build-up & Figure 9.13 ii. Harvest Figure 9.14 Figure 9.15

i. Build Up 1. NADH and FADH 2 drop the electrons from H to a series of re- dox proteins called cytochromes 2. As electrons move down the chain they lose energy which is used to move the H proton across the membrane to establish potential energy ii. Harvest 1. The electrons are eventually passed to an awaiting Oxygen atom 2. The H proton moves back across the membrane through ATP Synthase and to the waiting O 2 to form water 3. Conversion of energy (Potential to Kinetic) is used to form ATP

a. ATP is used b. NAD + and FAD + sent back to glycolysis or the Kreb’s cycle c. Water moved out or used 3. Outcomes

Summary of Aerobic Respiration Figure 9.16

only glycolysis A. Fermentation 1. Who? 2. Process Figure 9.17a III. Anaerobic Respiration

Animal cells == lactic acid shuttle and Liver Figure 9.17b A. Lactic Acid Shuttle 1. Who?2. Process

Figure 9.19 A. Routes B. Problems IV. Versatility

Figure 9.20 A. Mechanisms B. Sites V. Regulation