Understanding Photosynthesis and Cellular Respiration: Energy Processes in Living Organisms

1. Chapter #6 and 7 Photosynthesis and Cellular Respiration

2. The Need For Energy • Heterotrophs get energy from food • Heterotrophs require energy for all of life’s processes -digest food -grow -maintenance -repair -synthesis

3. ENERGY • All energy ultimately comes from the sun • Autotrophs -producers • Heterotrophs -consumers

4. ENERGY (2) • Photosynthesis -stores the energy • Respiration -releases the energy • Both photosynthesis and respiration have an ATP-ADP Cycle -provides the energy to the cells

5. ATP • Adenosine Triphosphate • Components: -adenine, ribose, 3 phosphates • Phosphorylation: -process of freeing a phosate from ATP (enzyme ATPase) making ADP -ATP synthetase then reattaches the phosphate group making ATP

6. ATP-ADP Cycle

7. Respiration • Process that releases chemical energy from food • Occurs in ALL cells • Reactants glucose, oxygen • Products carbon dioxide, energy, water

8. Photosynthesis • Process that converts radiant solar energy into chemical energy stored in organic molecules • Occurs in cells of autotrophs • Reactants carbon dioxide, water, light • Products carbohydrates, oxygen

9. Basis of Photosynthesis • Absorption of Sunlight • Light Dependent Reactions • Light Independent Reactions (Calvin-Benson Cycle) (all occurs within the chloroplast)

10. Chloroplast • Chlorophyll -light absorbing pigments • 3 membrane system -granum (stacks of thylakoid) -stroma (fluid) -increases the surface area for light absorption

12. Light Dependent Reactions • Occurs in the Thylakoids (grana) • First Stage -convert light to electrical energy using electron transport chain (photosystem I) -uses water, releases oxygen • Second Stage -convert electrical energy to chemical energy (ATP) (phtotsystem II)

13. Light Independent Reactions(Calvin-Benson Cycle) • CO2 and ATP enter the stroma • Binds to RuBP(5 carbon molecule) • RuBP splits into PGAL (3 carbon sugar made with the addition of Hydrogen from NADPH and ATP) • PGAL generates 1 glucose and regenerates RuBP to start the cycle over again • Completes 6 turns to get glucose (6 carbon sugar)

16. Alternative Pathways • C4 (corn, sugarcane, crabgrass) -more efficient at fixing carbon to form sugars • CAM (desert plants) -close stomata during the day to prevent water loss -trap carbon dioxide for the Calvin-Benson Cycle at night

17. Cellular Respiration • Aerobic -in the presence of oxygen • Anaerobic -occurs when oxygen is not present -causes fermentation (alcoholic and lactic acid)

20. Three Parts of Cellular Respiration… • Glycolysis • Kreb’s Cycle • Electron Transport Chain

21. Three Parts of Cellular Respiration… • Glycolysis • Kreb’s Cycle • Electron Transport Chain

22. GLYCOLYSIS • Occurs in the cytoplasm • Turns glucose into pyruvic acid • Net 2 ATP -4 are made and two are used • 2 NADH -electron carrier to be used during the last step of respiration

23. KREB’S CYCLE • Pyruvic acid turns into Acetyl-CoA -Produces 2 NADH • Enters the mitochondria • Produces -2 ATP -2 FADH2 -6 NADH

24. Products so far… • 4 ATP • 10 NADH • 2 FADH2

25. Electron Transport Chain • 2 FADH2 and 10 NADH enter the ETC • 1 FADH2 yields 2 ATP • 1 NADH yields 3 ATP • Total -4 ATP from FADH2 -30 ATP from NADH

26. How many ATP from respiration? • 38 ATP TOTAL

27. Fermentation • Occurs in the cytoplasm • Lactic Acid -muscle cells • Alcoholic -Yeasts -Bacteria

28. Anaerobic Respiration • Respiration w/o oxygen • Glycolysis • Glucose broken down to pyruvic acid (2ATP) • Oxygen is needed for pyruvic acid to enter the mitochondria so the process stops • Pyruvic Acid breaks down to Lactic Acid (animals) • Pyruvic Acid breaks down to Alcohol (yeast)

29. CHROMATOGRAPHY