1. Photosynthesis and Cellular Respiration Chapter 9

2. Basis of Photosynthesis Converts sunlight into chemical energy. Provides almost all energy for life. To convert cells must have chloroplasts. Chloroplast have a double membrane for protection but both membranes allow light to filter through. The space inside both membranes is the stroma which houses the thylakoid membrane which holds the thylakoids.

3. Thylakoids are stacks of sacs which absorb the sunlight when sunlight hits these stacks photosynthesis begins. Light and chemical energy. Remember light is radiation these radiations allow you to see certain pigments. In thylakoids there is chlorophyll a green pigment that absorbs the energy of light.

4. Pigment is a substance that absorbs certain wavelengths of color. Recall chlorophyll is a green pigment so it absorbs all colors but green. Electron carriers are the start of photosynthesis when light hits a thylakoid energy is absorbed it is funneled to the reaction center where electrons are excited and move up energy levels (electron shells) then to electron carriers.

5. Electron carriers transfer electrons to electron transport chains (2) One e.t.p. produces ATP One e.t.p. produces NADPH

6. Photosynthesis Production of ATP 1 st step : H2O splits to replace excited e- that leaves the chlorophyll. An enzyme splits H2O inside the thylakoid. As the H2O splits the H+ goes to chlorophyll the O molecules combine and form O2 which is replaced to the atmosphere

7. 2 nd Step : protein is a membrane pump for excess H+ that is pumped to the thylakoid. This creates a concentration gradient across thylakoid membranes 3 rd Step: (ATP creation): As H+ move through channels of proteins a phosphate is added to ADP creating ATP

8. Production of NADPH (2 nd ETP Chain) 4 th Step: light excited electrons pass to 2 nd E.T.P. chain replaced by de-energized e- from the first transport chain 5 th Step: e- with H+ go to NADP+ to create NADPH

9. Sugar Production (Light independent reaction) Calvin Cycle/ Krebs Cycle (Occurs in Stroma) 1 st step: Carbon fixation enzyme adds CO2 to 5 carbon compound 3 times for 3-6 carbon compound 2 nd step: Energy transfer 6 carbon compound splits to 2-3 carbon phosphate from ATP and NADPH are added to carbons for high energy 3- carbon sugar

10. 3 rd step : Creation of Sugar 1 of the resulting 3 carbons are used to make larger sugars 4 th step: The 5 remaining 3- carbon sugars are rearranged. Completing the cycle.

11. 3 factors that impact photosynthesis Light Amount of CO2 Temperature

12. Cellular Respiration Glucose is the starting unit for cellular respiration it comes from breaking down foods (starches, sucrose). If there are not enough carbs, fats re used to breakdown and fuel cellular respiration. Overall glucose is oxidized and O2 is reduced.

13. Stages of Cellular Respiration 1 st stage – GLYCOLYSIS - takes place in cytoplasm Step 1 : 2 ATP break a 6 – carbon glucose to two 3 carbon molecules with phosphate groups Step 2: 3 – carbon and phosphate reacts with a non-ATP phosphate creating NADH

14. Step 3: 4 reactions occur changing 3 carbons into pyruvate From there the organisms must decide if the next step is aerobic (with oxygen) or anaerobic (without oxygen)

15. Aerobic Respiration Uses oxygen and occurs in animals Can produce up to 34 ATP from one glucose Is a 2 step process (Kreb’s / citric acid cycle and then Electron transport chain

16. Kreb’s / Citric Acid Cycle Occurs in the matrix of the mitochondria Pyruvate (from glycolysis) releases CO2 becoming a 2 carbon compound. The 2 carbon attaches to a 4 carbon recreating a 6 – carbon molecule Eventually the new 6- carbon releases 2 CO2s creating NADH the remaining 4 carbon molecule is cycled back to the start compound producing ATP

17. Electron Transport Chain Occurs in mitochondrion Produces up to 34 ATP e- on NADH and FADH2 pass energy from e-. Transports H+ out of inner mitochondria these H+ diffuse and create energy which results in ATP creation at the end e- are use up and 2 H+ are left and combine with O to create H2O Overall e- are passed between carriers and release energy

18. Anaerobic Respiration (Fermentation) Starts with glycolysis and then in the absence of oxygen (O2) fermentation recycles NAD+. It allows cells to be supplied with ATP without the presence of the O2. 2 types 1.Lactic Acid Fermentation 2.Alcoholic Fermentation

19. Lactic Acid Fermentation Occurs in Animals Converts pyruvate to lactic acid Glycolysis is the source of ATP and production of lactic acid recycles the NAD+. Think lactate build up in unconditioned athletes.

20. Alcoholic Fermentation Occurs in yeasts, bacteria Pyruvate has carbon removed creating a 2 carbon molecule E- and H are added from NADH to the molecule creating ethanol NAD+ is recycled so glycolysis can produce ATP