1. Chapter 9 Energy in a Cell

2. Cells need energy, its essential to lifeCells need energy, its essential to life Our body has a source of energy available to usOur body has a source of energy available to us The energy is stored in the chemical bonds of ATPThe energy is stored in the chemical bonds of ATP

3. 9.1 ATP in a molecule ATP = adenosine triphosphateATP = adenosine triphosphate –Adenosine molecule –Three phosphates

4. ATP is a small compound that is a quick source of energyATP is a small compound that is a quick source of energy Binds to specific sites on a cellBinds to specific sites on a cell When phosphate bond broken, energy is released – cell uses this energyWhen phosphate bond broken, energy is released – cell uses this energy

5. ADP Adenosine Diphosphate Formed when a phosphate is cleaved from ATPFormed when a phosphate is cleaved from ATP –Releases energy

6. ADP can reform ATP which creates a renewable cycle of ATP formation and breakdownADP can reform ATP which creates a renewable cycle of ATP formation and breakdown This cycle continues as long as there are phosphate molecules availableThis cycle continues as long as there are phosphate molecules available

7. What do you think would happen if there were no more phosphate molecules available? What do you think would happen if there were no more phosphate molecules available?

8. ATP binds to a moleculeATP binds to a molecule Phosphate group is cleaved off and ADP leavesPhosphate group is cleaved off and ADP leaves –Phosphate group gives the cell its energy Another ADP molecule binds to the phosphate molecule and the process starts overAnother ADP molecule binds to the phosphate molecule and the process starts over

10. Cells use the energy for many purposesCells use the energy for many purposes –Physical activity –Making new enzymes to carry out chemical reactions –Build membranes and cell organelles –Maintain homeostasis –Dispose of waste substances

11. 9.2 Photosynthesis: Trapping the Sun ’ s Energy

12. PhotosynthesisPhotosynthesis 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 26CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 –Converts light energy into chemical energy –two phases Light-dependent + light-independentLight-dependent + light-independent –Builds carbohydrates that store energy –Produces ATP –Occurs in membranes of thylakoid discs

13. Thylakoid discsThylakoid discs –Located in chloroplasts –contain pigments that absorb light = chlorophyll

14. Light-dependent Reactions First phase of photosynthesisFirst phase of photosynthesis Sunlight hits plants and they absorb energySunlight hits plants and they absorb energy Transfer energy to electrons on the Electron Transport ChainTransfer energy to electrons on the Electron Transport Chain

15. Electron Transport Chain is a series of proteins embedded in thylakoid membraneElectron Transport Chain is a series of proteins embedded in thylakoid membrane

16. In the ETC, Energy is passed from protein to proteinIn the ETC, Energy is passed from protein to protein Each transfer a little bit of energy is releasedEach transfer a little bit of energy is released This energy is used to form ATP from ADPThis energy is used to form ATP from ADP

17. The ETC also splits a water molecule and hydrogen ions, H +, bind with an NADP + molecule forming NADPHThe ETC also splits a water molecule and hydrogen ions, H +, bind with an NADP + molecule forming NADPH NADPH is used to form carbohydrates in light-independent reactionsNADPH is used to form carbohydrates in light-independent reactions

18. Light-independent Reactions Calvin CycleCalvin Cycle –Takes place in the stroma of the chloroplast –5 steps – page 235 –Each step adds a CO 2 molecule –Takes 6 cycles to form a suga r

20. 9.3 Getting energy to make ATP

21. Cellular Respiration 3 stages3 stages –Glycolysis –Citric acid cycle –Electron transport chain

22. Glycolysis Anaerobic – no oxygenAnaerobic – no oxygen Occurs in the cytoplasmOccurs in the cytoplasm Break down glucose into pyruvic acidBreak down glucose into pyruvic acid ATP – 2 used, 4 produced; net gain of 2 moleculesATP – 2 used, 4 produced; net gain of 2 molecules

23. Pyruvic acid molecules move to mitochondria, loses a molecule of CO 2 and combines with coenzyme A to form acetyl-CoAPyruvic acid molecules move to mitochondria, loses a molecule of CO 2 and combines with coenzyme A to form acetyl-CoA

25. The Citric Acid Cycle Glucose is broken downGlucose is broken down One ATP molecule formedOne ATP molecule formed Charged electrons are carried via NADH & FADH 2 to the electron transport chain in the mitochondriaCharged electrons are carried via NADH & FADH 2 to the electron transport chain in the mitochondria

27. The Electron Transport Chain Energized electrons passed from protein to proteinEnergized electrons passed from protein to protein Mitochondria inner membrane becomes positive charged, due to high concentration of H + ionsMitochondria inner membrane becomes positive charged, due to high concentration of H + ions

28. Mitochondria outside membrane becomes negatively charged due to electrons on the outsideMitochondria outside membrane becomes negatively charged due to electrons on the outside A concentration gradient occurs: electrical & chemicalA concentration gradient occurs: electrical & chemical Electrical = charge differenceElectrical = charge difference Chemical = concentration differenceChemical = concentration difference

29. Inner membrane of mitochondria forms ATPInner membrane of mitochondria forms ATP Final electron acceptor is OxygenFinal electron acceptor is Oxygen 32 ATP molecules formed32 ATP molecules formed

31. 35 ATP produced overall35 ATP produced overall GlycolysisGlycolysis –2 ATP Citric Acid CycleCitric Acid Cycle –1 ATP Electron Transport ChainElectron Transport Chain –32 ATP

32. Fermentation

33. Lactic Acid Fermentation 2 molecules of pyruvic acid use NADH to form 2 molecules of lactic acid2 molecules of pyruvic acid use NADH to form 2 molecules of lactic acid 2 molecules ATP produced2 molecules ATP produced Muscle fatigue = lactic acid build-upMuscle fatigue = lactic acid build-up

34. Alcoholic Fermentation Yeast cells produce CO 2 and ethyl alcoholYeast cells produce CO 2 and ethyl alcohol Bread – yeast cells produce carbon dioxide that forms bubbles in dough, heat kills CO 2 & bubbles in dough lighten breadBread – yeast cells produce carbon dioxide that forms bubbles in dough, heat kills CO 2 & bubbles in dough lighten bread

35. Photosynthesis vs. Cellular Respiration Food accumulated CO 2 taken in Energy stored in glucose Occurs only in light Occurs only in presence of chlorophyll Food broken down CO 2 given off Energy released from glucose Occurs day & night Occurs in all living cells

36. The End