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Photosynthesis and Cellular Respiration. 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
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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)
+ 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
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
The chloroplast • Sites of photosynthesis • Pigment: chlorophyll • Plant cell: mesophyll • Gas exchange: stomata • Double membrane • Thylakoids, stack-granum • Stroma-fluid-filled interior
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!
Light reactions Convert solar energy to chemical energy ATP NADPH What can we do now? ATP energy reducing power build stuff !! photosynthesis
The Calvin Cycle 1950s | 1961 Whoops! Wrong Calvin…
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
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!
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
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!
What’s thepoint? The pointis to makeATP! ATP Cell Respiration 2006-2007
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)
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
(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
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
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
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
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!
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!
Pyruvate is a branching point O2 O2 fermentation anaerobicrespiration mitochondria Krebs cycle aerobic respiration Pyruvate
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
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