QOD – What is the fuel of the cell called?

1. QOD – What is the fuel of the cell called?

2. Making ATP from Glucose 9.3

3. Cellular Respiration • Cellular Respiration - is the process by which mitochondria break down food molecules to produce ATP. • Three Phases: • Glycolysis, citric acid cycle, and ETC

4. Glycolysis • Glycolysis is a series of chemical reactions in cytoplasm of a cell that break down glucose (6 carbon) into 2 molecules of pyruvic acid (3 carbon) • Requires 2 molecules of ATP to start glycolysis • Breaking down of glucose into pyruvic acid produces 4 ATP and 2 NADH and 2H+ • Anaerobic stage - doesn’t require oxygen

5. Glycolysis Glucose c 4 ATP 4 ADP 2 ATP 2 ADP 2 2 NAD + 2 NADH + 2H + P

6. End result 2 ATP – Needed to start Glycolysis 2 NADH Produced 4 ATP Produced Net Totals: 2 NADH 2 ATP 2 Pyruvates

7. NADH • NAD+ is an electron carrier • Created during glycolysis when Glucose is broken down into pyruvic acid • Two energized electrons are added to NAD+ to create NADH and H+

8. Glycolysis • Glycolysis Movie

9. To the mitochondria • The two molecules of pyruvic acid enter the mitochondria • They undergo a series of reactions before moving on to the second stage, citric acid cycle • Pyruvic acid is changed in a series of reactions • Releases CO2 • Joins with Coenzyme A • End result is acetyl-CoA (2 Carbon) • Produces one NADH and H+

10. Pyruvic acid ---> acetyl-CoA CO2 NAD+ NADH + H+

11. Citric Acid Cycle • Also called the Krebs Cycle • Aerobic reaction - needs oxygen to occur • Is a series of chemical reactions (similar to the Calvin Cycle) in which the molecule used in the first reaction is the end product. • End result for 1 cycle: • 1 ATP • 3 NADH • 1 FADH2 • 3 H+ • The electron carrier molecules NADH and FADH2 take the energized electrons to the ETC • Found in the inner membrane of the mitochondria

12. Steps of Krebs Cycle • Acetyl-CoA enters the Krebs Cycle and combines with the oxaloacetic acid (4carbon) to form citric acid (6 carbon) • Citric acid (6 carbon) releases a carbon to form CO2 and in the process creates NADH and H+. End result is a 5 carbon structure. • A second CO2 is produced when the 5 carbon structure releases a carbon and in the process ATP and NADH and H+ are produced. End result is a 4 carbon structure.

13. Steps of Krebs Cycle 4. The 4 carbon structure goes through a series of reactions to reform oxaloacetic acid to ensure the cycle is able to continue. 5. 1st reaction - produces a FADH2 6. 2nd reaction - no byproducts 7. 3rd reaction - NADH and H+ form 8. Formation of Oxaloacetic acid

14. Citric Acid Cycle • Video

15. ETC • Location: inner membrane of Mitochondria • NADH and FADH2 take the energized electrons to the ETC • Electrons are passed from protein to protein in the ETC slowly releasing their energy in steps • Some can be used to form ATP • Some can be used by an enzyme to pump H+ ions into the center of the mitochondria • Aerobic reaction - requires oxygen to occur

16. Importance of H+ ions • The inner membrane becomes positively charged • The exterior membrane becomes negatively charged • Which attracts H+ ions(because they are positive) • The gradient of H+ ions created provides the energy needed to create ATP

17. ETC • The final electron acceptor is oxygen which forms 2 waters, when oxygen reactions with four H+ and 4 electrons (lost their energy) • Why we need oxygen, otherwise we would have a build up of electrons, until the ETC could no longer accept anymore electrons and would no longer function

18. ETC End Results • Overall the ETC produces • 32 ATP • Water • NAD+ • FAD+

19. ETC • ETC in cellular respiration

20. Overall • Cellular Respiration creates • 36 ATP • 6 NADH • 1 FADH2 • 3 CO2 • H2O • 6 H+

21. Fermentation • An anaerobic process that occurs in the absence of oxygen for short periods of time that allows ATP to be created until oxygen can be restored • During heavy exercise • Two major types • Lactic Acid Fermentation • Alcoholic Fermentation

22. Compare Fermentation to Cellular Respiration

23. Lactic Acid Fermentation • Process that supplies energy when oxygen is limited • Without oxygen the ETC begins to back up and it can no longer accept electrons • Therefore there is no NAD+ or FAD+ to supply to the citric acid cycle or glycolysis • NAD+ can still be created without oxygen but FAD+ can not

24. How it works • Two molecules of pyruvic acid use NADH to form 2 molecules of lactic acid • This release NAD+ which can be used in glycolysis allowing 2 ATP • During extreme exercise muscle cells produce lactic acid, but after it is used to create NAD+ it travels to the liver to be turned back into pyruvic acid • Lactic acid build up in the muscle cells causes muscle fatigue and soreness

25. Alcoholic Fermentation • Alcoholic fermentation is used by yeast and some bacteria cells to produce CO2 and ethyl alcohol. • Yeast - used to make bread rise by releasing CO2. The heat from baking does kill the yeast. • Bacteria - used to create alcohol from fruits and plants

26. Compare Cellular Respiration to Photosynthesis • Similarities • Both use ETC • Both use cycles of chemical reactions to form ATP • Both create a concentration gradient of H+ by using a Hrydrogen ion pump • Both utilize PGAL • Differences: • Cellular Res. • Produces ATP • Gives off CO2 • Doesn’t require light • Occurs in plants and animals • Energy carrier NADH and FADH2 • Photosynthesis • Produces Glucose • Requires light • Gives off oxygen • Occurs only in plants or cells with chlorophyll • Energy carrier NADPH