light dependent reaction In the light dependent reaction, solar energy is captured by pigments in the thylakoid membrane in the chloroplasts and used to attach phosphate groups to energy-carrying molecules like ATP. Previously, we learned that photosynthesis takes place in the chloroplasts A QUICK PSN REVIEW

ATPNADPH light dependent reaction In the CALVIN CYCLE, the ATP and NADPH made in the light dependent reaction are used to power the assembly of sugars in the stroma, the fluid-filled interior of the chloroplasts. This completes the equation for photosynthesis: 6 CO H 2 0 C 6 H 12 O O 2

So now we have energy stored in the form of sugars. Very nice, but what if plants (or, for that matter, people) want to release that energy? THEY MUST USE A DIFFERENT PATH….

RETAKE QUIZ TOMORROW

CELLULAR RESPIRATION HARVESTING CHEMICAL ENERGY ATP

CELLULAR RESPIRATION (RSP) Next, we’ll need another organelle to do these chloroplasts reactions in! Not chloroplasts this time, but instead another organelle with its own DNA…. REVERSE FIRST, WE REVERSE THE EQUATION: 6 CO H 2 0 C 6 H 12 O O 2

MITOCHONDRIA:

CELLULAR RESPIRATION: HARVESTING ENERGY FROM FOOD  The “Furnace” for making energy  mitochondria  Fuel  food: carbohydrates, fats, proteins  Helpers  Oxygen  enzymes  Product  ATP  Waste products  carbon dioxide  water O2O2 food ATP enzymes CO 2 H2OH2O

MITOCHONDRIA ARE IN animal cells plant cells

3 STAGE PROCESS

STAGE 1: GLYCOLYSIS Break a sugar into 2 pyruvic acids Small 3 Carbon chunks easier to use Happens in cytoplasm Net 2 ATP gain Make NADH Energy storage NO O 2 needed

STAGE 2: KREBS CYCLE Break pyruvic acid into CO 2 releasing ENERGY Happens in matrix Net 2 ATP gain Make NADH O 2 needed

STAGE 3: ELECTRON TRANSPORT CHAIN Uses high energy electrons from Glycolysis and Krebs Cycle to change ADP to ATP

TOTAL ENERGY Glycolysis Glycolysis, in cytoplasm, no O 2 Krebs Cycle Krebs Cycle, in matrix, with O 2 Electron transport chain Electron transport chain, with O 2 ATP 2 ATP ATP 32 ATP 36 ATP per 1 molecule Sugar

ATP + CO 2 + H 2 O (+ heat) OUR CELLS NEED TO RELEASE ENERGY SLOWLY ATP aerobic respiration making ATP energy (& some heat) by burning fuels in many small steps Food (carbohydrates) O2O2

make energy A BODY’S ENERGY BUDGET eat food synthesis (building) energy needed even at rest activity temperature control { growth reproduction repair { storage glycogen (animal starch) fat { ATP 1 2 3

Can’t store ATP  too unstable  only used in cell that produces it  only short term energy storage  carbohydrates & fats are long term energy storage USING ATP TO DO WORK A working muscle recycles over 10 million ATPs per second ATP ADP work Adenosine DiPhosphate Adenosine TriPhosphate

 ATP already in muscles quickly used up  ATP produced by cellular respiration (more ATP, but not made fast enough) QUICK ENERGY -90 SEC

 Any sustained exercise depends almost solely upon cellular respiration.  Even elite distance runners have to pace themselves to keep their supply of oxygen high enough.  Will change over to anerobic respiration to keep up with energy demands ENERGY +90SEC TO 20MIN

 Start breaking down fats for energy. ENERGY +20 MINUTES

WHAT IF OXYGEN IS MISSING?  No oxygen available = can’t complete aerobic respiration  Anaerobic respiration  also known as fermentation  alcohol fermentation  lactic acid fermentation  no oxygen or no mitochondria (bacteria)  can only make very little ATP  large animals cannot survive O2O2 yeast bacteria

ANAEROBIC RESPIRATION AKA FERMENTATION  alcohol fermentation  yeast  glucose  ATP + CO 2 + alcohol  make beer, wine, bread  lactic acid fermentation  bacteria, animals  glucose  ATP + lactic acid  animals feel muscle fatigue  Organisms change our food O2O2

FERMENATION

 Aerobic?  With oxygen  What part(s) of the cellular respiration pathway is (are) aerobic?  Krebs Cycle and Electron Transport Chain  Why Krebs Cycle?  Anaerobic?  Without oxygen  What part of the cellular respiration pathway is anaerobic?  Glycolysis  Can happen without oxygen ANAEROBIC VERSUS AEROBIC

STANDARDS: “The gradual combustion of carbon-containing compounds within cells, called cellular respiration, provides the primary energy source of living organisms” mitochondriachemical glucose “Students know that in both plants and animals, mitochondria make stored chemical bond energy available to cells by completing the breakdown of glucose to carbon dioxide!”

 Write and label the cellular respiration equation to show where the product or reactant is being used or produced.  G = glycolysis  KC = Krebs Cycle  ETC = Electron Transport Chain. C 6 H 12 O O 2 → 6 CO H 2 O + energy OPENER 2/25 – PG. 119