2. Today: Kreb’s Cycle Today: Kreb’s Cycle –Cell Respiration Homework Due Monday: Electron Transport Chain, Monday: Electron Transport Chain, Pre-lab assignment due Thursday (typed and shared) Pre-lab assignment due Thursday (typed and shared) Tuesday: Workday Tuesday: Workday Wednesday: Family Reunion Wednesday: Family Reunion Thursday: Cellular Respiration Review, Thursday: Cellular Respiration Review, Read lab procedures for homework (emailed or on Google Drive) Read lab procedures for homework (emailed or on Google Drive) Friday: Cellular Respiration Lab Friday: Cellular Respiration Lab Monday, 12/1: Cell Communication Independent Study (Test grade) Monday, 12/1: Cell Communication Independent Study (Test grade)

3. Graph data and calculate the reaction rate. Explain why a change in reaction rate was observed after so many minutes. Draw and label another line on the graph to predict the results if the concentration of the enzyme was doubled. Explain results. Identify TWO environmental factors that can change the rate of enzyme-mediated reactions. Discuss how each of those two factors would affect the reaction rate of an enzyme.

4. 2007-2008 Cellular Respiration

5. 2007-2008 What’s the point? The point is to make ATP ! ATP

7. Glycolysis Step 1: Glycolysis Breaking down glucose – “glyco – lysis” (splitting sugar) – ancient pathway which harvests energy where energy transfer first evolved transfer energy from organic molecules to ATP still is starting point for all cellular respiration – but it’s inefficient generate only 2 ATP for every 1 glucose – occurs in cytosol – anaerobic process glucose      pyruvate 2x2x 6C3C

9. Evolutionary Perspective Prokaryotes – first cells had no organelles (NO MITOCHONDRIA) Anaerobic atmosphere – life on Earth first evolved without free oxygen (O 2 ) in atmosphere – energy had to be captured from organic molecules in absence of O 2 Prokaryotes that evolved glycolysis are ancestors of all modern life – ALL cells still utilize glycolysis

10. OVERVIEW 10 reactions – convert glucose (6C) to 2 pyruvate (3C) – produces: 4 ATP & 2 NADH – consumes: 2 ATP – net: 2 ATP & 2 NADH glucose C-C-C-C-C-C fructose-1,6bP P-C-C-C-C-C-C-P DHAP P-C-C-C G3P C-C-C-P pyruvate C-C-C DHAP = dihydroxyacetone phosphate G3P = glyceraldehyde-3-phosphate ATP 2 ADP 2 ATP 4 ADP 4 NAD + 2 2 2Pi2Pi enzyme 2Pi2Pi 2H2H

11. Glycolysis summary endergonic invest some ATP exergonic harvest a little ATP & a little NADH yield 2 ATP 2 NADH like $$ in the bank 4ATP ENERGY INVESTMENT ENERGY PAYOFF G3P C-C-C-P NET YIELD

12. IS THAT IT?! Not a lot of energy… – for 1 billon years + this is how life on Earth survived no O 2 = slow growth, slow reproduction only harvest 3.5% of energy stored in glucose – more carbons to strip off = more energy to harvest Hard way to make a living! O2O2 O2O2 O2O2 O2O2 O2O2 glucose     pyruvate 6C 2x2x 3C

14. Fermentation (anaerobic) Bacteria, yeast 1C 3C2C pyruvate  ethanol + CO 2 Animals, some fungi pyruvate  lactic acid 3C  Makes beer, wine, bread  cheese, anaerobic exercise (no O 2 ) NADHNAD + NADHNAD + to glycolysis 

15. Alcohol Fermentation 1C 3C2C pyruvate  ethanol + CO 2 NADHNAD + Count the carbons!  Dead end process  at ~12% ethanol, kills yeast  can’t reverse the reaction bacteria yeast

16.  Reversible process  once O 2 is available, lactate is converted back to pyruvate by the liver Lactic Acid Fermentation pyruvate  lactic acid 3C NADHNAD +  Count the carbons! O2O2 animals

17. Pyruvate is a branching point!!! Pyruvate O2O2 O2O2 mitochondria Kreb’s cycle aerobic respiration fermentation anaerobic respiration

18. 2007-2008 What’s the point? The point is to make ATP ! ATP

19. H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ And how do we do that? ATP synthase – set up a H + gradient – allow H + to flow through ATP synthase – powers bonding of P i to ADP ADP + P i  ATP ATP But… Have we done that yet? ADP P +

20. 2007-2008 NO! There’s still more to my story! Any Questions? Glycolysis Rap Song Glycolysis Rap Song

21. 2 ATP CO 2 out O 2 in 2 ATP e- in 2 NADH H 2 O out 30+ ATP

23. CELLULAR RESPIRATION Step 2 THE CITRIC ACID CYCLE OR THE KREB’S CYCLE

24. The most important link to the electron transport chain (ETC makes a ton of ATP) Occurs in mitochondrial matrix Some bacteria too (takes place in cytoplasm) Sir Hans Adolf Krebs, 1937 BETWEEN GLYCOLYSIS AND CITRIC ACID CYCLE: pyruvateacetyl- CoA Coenzyme A CO 2 NADH Kreb’s Cycle

25. Initiating step of Citric Acid Cycle: 4-C oxaloacetic acid + 2-C acetyl CoA 6-C citric acid During the cycle: – Citric acid rearranged; Stripped of 2-Cs – CO2 released – 4 e- released to electron carriers (NAD+ and FAD) – 1 molecule of oxaloacetic acid remains to begin the cycle again – 2 ATP made Oxidation Reactions!!! – molecules that lose electrons…LEO goes GER – Loss of electrons at 4 specific places…to fuel ETC – Use NAD+ and FAD – Steps 4, 6, 10 (NAD+) & 8 (FAD)

29. Page 183 – 184 #s 1 – 15 Typed in full sentences.