Photosynthesis and Cellular Respiration

1. Photosynthesis and Cellular Respiration

2. Photosynthesis in nature • According to the way they obtain energy, all living things can be divided into : • Autotrophs:producers; obtains organic food without eating other organisms • Heterotrophs:consumers;obtains organic food by eating other organisms or their by-products (includes decomposers)

3. + water + energy  glucose + oxygen carbon dioxide glucose + oxygen  carbon + water + energy  C6H12O6 + 6O2 6CO2 + 6H2O + ATP dioxide light energy  6CO2 + 6H2O + + 6O2 C6H12O6 How are they connected? Heterotrophs making energy & organic molecules from ingesting organic molecules oxidation = exergonic Autotrophs Where’s the ATP? making energy & organic molecules from light energy reduction = endergonic

4. glucose H2O CO2 N K P … What does it mean to be a plplantant ATP • Need to… • collect light energy • store light energy • need to get building block atomsfrom the environment • C,H,O,N,P,K,S,Mg • produce all organic moleculesneeded for growth • carbohydrates, proteins, lipids, nucleic acids

5. The chloroplast • Sites of photosynthesis • Pigment: chlorophyll • Plant cell: mesophyll • Gas exchange: stomata • Double membrane • Thylakoids, stack-granum • Stroma-fluid-filled interior

6. Photosynthesis • Light reactions • light-dependent reactions • energy conversion reactions • convert solar energy to chemical energy • Calvin cycle • light-independent reactions • sugar building reactions • uses chemical energy (ATP) to synthesize glucose (C6H12O6) It’s not theDark Reactions!

7. Light reactions Convert solar energy to chemical energy ATP NADPH What can we do now? ATP  energy  reducing power   build stuff !! photosynthesis

8. The Calvin Cycle 1950s | 1961 Whoops! Wrong Calvin…

9. How is that helpful? Want to make C6H12O6 synthesis How? From what? What raw materials are available? C6H12O6 NADP CO2 NADPH reduces CO2 carbon fixation NADP

10. RuBisCo Enzyme which fixes carbon from air ribulose bisphosphate carboxylase the most important enzyme in the world! it makes life out of air! definitely the most abundant enzyme It’s not easy being green! I’m green with envy!

11. Putting it all together light energy  CO2 + H2O + C6H12O6 + O2 sunlight Plants make both: • energy • ATP & NADPH • sugars H2O CO2 ADP NADP SugarBuilding Reactions Energy Building Reactions NADPH ATP sugars O2

12. Energy cycle sun light energy  CO2 + H2O + + O2 C6H12O6 glucose H2O ATP energy  + O2 + CO2 + H2O C6H12O6 even thoughthis equationis a bit of a lie…it makes a better story Photosynthesis plants CO2 O2 animals, plants Cellular Respiration ATP The Great Circleof Life,Mufasa!

13. You can grow if you Ask Questions!

14. What’s thepoint? The pointis to makeATP! ATP Cell Respiration 2006-2007

15. What is Cell Respiration? glucose + oxygen  energy + water + carbon dioxide respiration ATP + 6H2O + 6CO2 + heat  C6H12O6 + 6O2 COMBUSTION = making a lot of heat, energy by burning fuels in one step ATP glucose O2 O2 fuel(carbohydrates) RESPIRATION = making ATP (& some heat)by burning fuels in many small steps ATP enzymes CO2 + H2O + heat • A series of reactions that break down molecules to produce energy • OR thecatabolism of glucose to produce ATP CO2 + H2O + ATP (+ heat)

16. The reactions are called REDOX Oxidation & reduction oxidation  C6H12O6 + 6O2 6CO2 + 6H2O + ATP reduction • Oxidation • adding O • removing H • releases energy • exotermic • Reduction • removing O • adding H • stores energy • endotermic

17. (1)Glycolysis glucose      pyruvate 6C 3C 2x In thecytoplasm?Why doesthat makeevolutionarysense? That’s not enoughATP for me! • Breaking down glucose • “glyco – lysis” (splitting sugar) • but it’s inefficient • generate only2 ATP for every 1 glucose • occurs in cytoplasm

18. Is that all there is? O2 O2 O2 O2 O2 3C 2x glucose     pyruvate 6C Hard wayto makea living! • Not a lot of energy… • for 1 billon years+ this is how life on Earth survived • no O2 = slow growth, slow reproduction • only harvest 3.5% of energy stored in glucose • more carbons to strip off = more energy to harvest

19. How many types of Cell Respiration? without oxygen anaerobic respiration “fermentation” with oxygen aerobic respiration pyruvate H2O NAD+ CO2 NADH NADH O2 acetaldehyde which path you use depends on who you are… NADH acetyl-CoA NAD+ NAD+ lactate lactic acidfermentation Krebs cycle ethanol alcoholfermentation

20. Fermentation (anaerobic) pyruvate  ethanol + CO2 3C 2C 1C pyruvate  lactic acid NADH NADH NAD+ NAD+ 3C 3C back to glycolysis • beer, wine, bread • Animals, some fungi back to glycolysis • cheese, anaerobic exercise (no O2) Bacteria, yeast

21. Alcohol Fermentation pyruvate  ethanol + CO2 3C 2C 1C NADH NAD+ recycleNADH bacteria yeast back to glycolysis • Dead end process • at ~12% ethanol, kills yeast • can’t reverse the reaction • Generates only 2 ATP! Count thecarbons!

22. Lactic Acid Fermentation O2 pyruvate  lactic acid NADH NAD+ 3C 3C recycleNADH animalssome fungi  back to glycolysis • Reversible process • once O2 is available, lactate is converted back to pyruvate by the liver • Generates only 2 ATP Count thecarbons!

23. Pyruvate is a branching point O2 O2 fermentation anaerobicrespiration mitochondria Krebs cycle aerobic respiration Pyruvate

24. ATP accounting so far… Glycolysis 2ATP Kreb’s cycle 2ATP There’s got to be a better way! It is called ELECTRON TRANSPORT CHAIN and makes LOTS of ATP !!! I need a lotmore ATP! A working muscle recycles over 10 million ATPs per second

25. Counting the energy released in AEROBIC RESPIRATION Glycolysis brings : 2 ATP Kreb’s Cycle brings: 2 ATP) Electron transport brings: From glycolysis = 6ATP From acetyl CoA = 6ATPFrom Kreb’s cycle = 22 ATP 38 TOTAL ATP/one molecule of glucose