1. Photosynthesis and Cellular RespirationSection 3 CH7: Cellular Respiration pg 131

2. Photosynthesis and Cellular RespirationSection 3 Glycolysis The primary fuel for cellular respiration is glucose. Equation for Photosynthesis 6CO 2 + 6H 2 O + pigment + sunlight  C 6 H 12 O 6 + 6O 2 Equation for Cellular Respiration C 6 H 12 O 6 + O 2  CO 2 + H 2 O + ENERGY (ATP)

3. Photosynthesis and Cellular RespirationSection 3 Glycolysis, continued In glycolysis, enzymes break down one six-carbon molecule of glucose into two three-carbon pyruvate molecules. The breaking of a sugar molecule by glycolysis results in a net gain of two ATP molecules. This process of glycolysis is anaerobic, or takes place without oxygen in the cytoplasm.

4. Photosynthesis and Cellular RespirationSection 3 Glycolysis, continued Glycolysis is the only source of energy for some prokaryotes. Other organisms use oxygen to release even more energy from a glucose molecule. –Metabolic processes that require oxygen are aerobic.

5. Photosynthesis and Cellular RespirationSection 3 Glycolysis, continued Step 1, Breaking Down Glucose –Two ATP molecules are used to break glucose into two smaller units. –Phosphate is attached to these 2 – three carbon sugars (G3P)

6. Photosynthesis and Cellular RespirationSection 3 Step 2, NADH Production –Each of the three carbon sugars (G3P) react with another phosphate (not ATP) –Hydrogen atoms from these compounds transfer to two molecules of NAD + resulting in 2 NADH molecules (Hydrogen ion/proton and e- carrier) Glycolysis, continued

7. Photosynthesis and Cellular RespirationSection 3 Glycolysis, continued Step 3, Pyruvate Production –In a series of 4 reactions, each of the 3 – carbon sugars are converted into a 3 – carbon molecule of pyruvate, resulting in 4 ATP molecules. BUT 2 ATP molecules were used in step one, so net total for glycolysis is 2 ATP molecules

8. Photosynthesis and Cellular RespirationSection 3 Glycolysis

9. Photosynthesis and Cellular RespirationSection 3 Fermentation To make ATP during glycolysis, NAD+ is converted to NADH. –Organisms must recycle NAD+ to continue making ATP through glycolysis. The process in which carbohydrates are broken down in the absence of oxygen is called fermentation. –Allowing glycolysis to continue supplying a cell with ATP in anaerobic conditions.

10. Photosynthesis and Cellular RespirationSection 3 PathwayReaction Lactic Acid Fermentation PYRUVIC ACID + NADH  LACTIC ACID + NAD+ *occurs in muscle cells for short term energy production, also used in the production of foods ex. yogurt, Kim chi, sauerkraut Alcoholic Fermentation PYRUVIC ACID + NADH  ALCOHOL+ CO 2 + NAD+ *occurs in yeast cells and is used in the production of beer, wine and bread

11. Photosynthesis and Cellular RespirationSection 3 Two Types of Fermentation

12. Photosynthesis and Cellular RespirationSection 3 Add this onto your Cellular Respiration illustration

13. Photosynthesis and Cellular RespirationSection 3 Aerobic Respiration The first stage of aerobic respiration is the Krebs cycle, a series of reactions that produce electron carriers (NADH and FADH 2 ). The electron carriers enter an electron transport chain, which powers ATP synthase. Up to 38 ATP molecules can be produced from one glucose molecule in aerobic respiration.

14. Photosynthesis and Cellular RespirationSection 3

15. Photosynthesis and Cellular RespirationSection 3 Kreb’s Cycle Pyruvate (from glycolysis) is broken down and combined with other carbon compounds creating CoA. –Releasing CO 2 The total yield of energy-storing products from the Krebs cycle is 2 ATP, 6 NADH, and 2 FADH 2.

16. Photosynthesis and Cellular RespirationSection 3

17. Photosynthesis and Cellular RespirationSection 3

18. Photosynthesis and Cellular RespirationSection 3 Electron Transport Chain The second stage of aerobic respiration takes place in the inner membranes of mitochondria –ATP synthase are located here Electron carriers (NADH and FADH 2 ), from the Krebs cycle –transfer energy in the form of e- and H+ into the electron transport chain. –e- are used to pump the H+ across the membrane to create a concentration gradient

19. Photosynthesis and Cellular RespirationSection 3

20. Photosynthesis and Cellular RespirationSection 3 Electron Transport Chain ATP Production Hydrogen ions diffuse through ATP synthase, providing energy to produce several ATP molecules from ADP.

21. Photosynthesis and Cellular RespirationSection 3 End of the ETC, the e- combine with an oxygen atom and two hydrogen ions to form two water molecules. If oxygen is not present, the electron transport chain stops. The electron carriers are not recycled, so the Krebs cycle also stops. The Role of Oxygen

22. Photosynthesis and Cellular RespirationSection 3 Efficiency of Cellular Respiration In the first stage of cellular respiration, glucose is broken down to pyruvate during glycolysis, an anaerobic process. Glycolysis results in 2 ATP molecules for each glucose molecule that is broken down. In the 2 nd stage, pyruvate EITHER passes through the Krebs cycle OR undergoes fermentation. –Fermentation recycles NAD+ but does not produce ATP.

23. Photosynthesis and Cellular RespirationSection 3 Efficiency of Cellular Respiration cont’d Cells release energy most efficiently when oxygen is present For each glucose molecule that is broken down, as many as 2 ATP molecules are made during the Krebs cycle. The Krebs cycle feeds NADH and FADH 2 to the ETC, which can produce up to 34 ATP molecules.

24. Photosynthesis and Cellular RespirationSection 3 Summary Cellular Respiration ReactantsProductsLocation GycolysisGlucose, 2 ATP2 Pyruvates, 2NADH, 4 (2) ATP Cytoplasm Krebs Cycle2 AcetylCoA (CoA)CO 2, 6NADH, 2FADH 2,2ATP Matrix of Mitochondria ETC6 NADH, 2FADH 2, O 2 34 ATP, H 2 O, 6NAD, 2FAD Inner Mitochondrial Membrane