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Cellular Respiration Producing ATP from the energy in food.

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Presentation on theme: "Cellular Respiration Producing ATP from the energy in food."— Presentation transcript:

1 Cellular Respiration Producing ATP from the energy in food

2 An Overview n ATP is immediate source of energy used by cells n Energy in ATP held in phosphodiester bonds n Most energy release in cells results from redox rxns. involving Glucose n C 6 H 12 O 6 + O 2 --> 6 CO 2 + 6 H 2 O + energy

3 n 40% of energy in Glucose is converted to usable energy in ATP n Production of ATP and other organic molecules is endergonic and require a constant input of energy to continue. n The source of that energy is the sun. n Photosynthesis is essentially the opposite of Cellular Respiration. n Energy flows from sun to autotrophs to heterotrophs. n All energy is lost eventually as work or heat.

4 Cellular Respiration THE BEGINNING *GLYCOLYSIS

5 Glycolysis n Activation of Glucose u 1 ATP used to add “P” to Glucose u forms Glucose Phosphate F Fructose Phosphate then formed F 1 ATP - P = 1 ADP + P

6 n Formation of Sugar Diphosphate u 1 ATP used to add “P” to Fructose Phosphate F Forms Sugar Diphosphate (sugar and two “P”’s) F 1 ATP - P = 1 ADP + P

7 n Formation and Oxidation of G3P u Sugar Diphosphate (6 C) into two 3 C molecules F 1 into G3P F Other 3 C becomes a different 3 C, but is then converted into G3P F Both G3P’s lose an H Accepted by NAD to make 2 NADH’sAccepted by NAD to make 2 NADH’s High energy level e - ’s carried by the H’sHigh energy level e - ’s carried by the H’s Some of the energy used to make 2 ATP’sSome of the energy used to make 2 ATP’s

8 n Formation of Pyruvate u 3 more reactions make two Pyruvate molecules u The energy released from these reactions used to make 2 ATP’s F Two C 3 H 4 O 3 = 6 C’s, 8 H’s, 6 O’s (just 4 H’s removed from Glucose, C 6 H 12 O 6.

9 Summary of Glycolysis n Glucose split into two 3 C’s u 2 ATP’s used for activation energy u 2 molecules NADH produced (+ 2 H + ) u 4 ATP’s made (net gain of 2 ATP’s) n Pyruvate is the 3 C made u Will next enter Kreb’s Cycle if Oxygen is available u Will undergo fermentation if no Oxygen is available n Occurs in cytoplasm n No oxygen required (but can be present)

10 The Oxidation of Pyruvate A necessary first step prior to either The Citric Acid Cycle or Fermentation

11 Oxidation of Pyruvate n 2 e - and their associated H released u 1 e - from each Pyruvate u Accepted by 2 NAD’s to form 2 NADH’s n A C also released from each pyruvate u forms two CO 2 ’s n Results in formation of two acetyl groups

12 The Citric Acid Cycle n Occurs in mitochondria n An aerobic process n Begins with acetyl (or Pyruvate if you include the oxidation of pyruvate as part of this process) n Ends with CO 2,H 2 O, NADH and FADH 2 and some ATP being produced

13 The process n Acetyl groups combine with a coenzyme u the coenzyme is CoA u just “hanging around” in mitochondria u forms AcetylCoA n AcetylCoA joins a 4C compound already present u The 4 C is oxaloacetic Acid u forms Citric Acid (6C) n Citric Acid undergoes two rxns to form isocitric acid

14 n Isocitric Acid is oxidized u The H’s released are accepted by NAD and FAD F forms 4 NADH and two FADH 2 F some of the energhy used to form two more ATP molecules u Forms Fumaric Acid n Fumaric Acid undergoes 2 rxns u Forms Oxaloacetic Acid u Combines with AcetylCoA to form Citric Acid u The whole darn thing happens again! u Two more NADH’s produced

15 n 2NADH produce in the Oxidation of Pyruvate n 2ATP’s produced in Citric Acid Cycle n 6 NADH and 2 FADH 2 also produced in Citric Acid Cycle n Add that to the net gain of 2 ATP and 4 NADH produced in glycolysis u 4ATP u 10 NADH u 2 FADH 2

16 Electron Transport Chain n Utilizing the energy held in NADH and FADH 2 previously produced to make ATP n Produced by chemiosmosis n Gradient produced b/w the area within the inner and outer mitochondrial membrane and inside the mitochondria n 2 NADH from glycolysis were actively transported in (required 1 ATP each)

17 The ETC n High energy e - ’s carried by NADH and FADH 2 transported out of inner mitochondrial membrane into area b/w inner and outer membrane by cytochromes embedded in the membrane. u protons follow u e - accepted by Oxygen to form H 2 O u creates proton conc. gradient n Protons move back across membrane in response to gradient n Movement coupled to production of ATP

18 The Balance Sheet from ETC n Each NADH drives synthesis of 3 ATP u 10 NADH from glycolysis, oxidation of pyruvate and the citric acid cycle u 30 ATP u but the NADH’s from glycolysis cost 1 ATP each to transport (- 2 ATP) n Each FADH 2 drives synthesis of 2 ATP u 2 FADH 2 ‘s from Citric acid cycle u 4 ATP n Net gain from ETC = 32 ATP

19 Overview of Oxidative Metabolism n Glycolysis u 2ATP (net gain), 2 NADH u anaerobic, in cytoplasm n Oxidation of Pyruvate u 2 NADH n Citric Acid Cycle u 2ATP, 6 NADH, 2 FADH 2 u aerobic, in mitochondria n ETC u 32 ATP (net gain), H 2 O u in christae of mitochondria

20 Fermentation Anaerobic Respiration: allowing Glycolysis to continue without O 2

21 Alcoholic Fermentation n Pyruvate from glycolysis is oxidized u forms acetyl u CO 2 also formed n Acetyl combines with H from NADH (from gly) u forms ethyl alcohol u also forms NAD to be used in glycolysis n Alcohol becomes toxic @ 12 % u ceases fermentation u thats why fermented drinks have max alcohol of 12% n Uses: wine, brewing, baking

22 Lactic Acid Fermentation n Pyruvate from glycolysis doesnt get oxidized u an enzyme helps to bond H from NADH to pyruvate u forms Lactic Acid - “Ooooh feel the burn!” u makes NAD available for glycolysis to continue n Occurs in aerobic cells under O 2 stress - muscle n Also occurs in certain other microorganisms u sour cream, yogurt u vinegar

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