2. Unit 10 Photosynthesis Plants use energy from the sun and convert it to chemical energy –Glucose Photosynthesis occurs in chloroplasts Capture of light energy (light dependent rxn) –In chlorophyll molecule in the thylakoid membrane Carbon fixation (light independent rxn) –In stroma, carbon dioxide is “fixed” into a carbohydrate molecule

3. Exercise 10.1 Wavelengths of transmitted light Wavelengths of light that are seen are reflected, or transmitted. Wavelengths that are absorbed are not seen by human eye. Pigments absorb wavelengths of light to spilt water during the Light Reaction. –Chlorophyll a- reflect green –Chlorophyll b- reflect green –Carotenoids- reflect red-orange-yellow What wavelengths do these pigments absorb?

4. Use spectroscope to view white light. What wavelengths are absorbed by different colored filters? What wavelengths are absorbed by spinach extract?

6. Exercise 10.2 Determine absorption spectrum of photosynthetic pigments Review use of spectrophotometer (Unit 3) Spinach extract Carrot extract Measure the absorbance of extracts at varying wavelengths. –Start with 525 nm, then vary. –Must calibrate spec with blank each time wavelength is changed

7. Hint: Measure spinach and carrot at a particular wavelength, then move to next wavelength. Graph results. –Graph both % transmittance and absorbance Determine at which wavelengths the pigments in spinach and carrot has maximum absorption.

8. 10.3 Pigment chromatography Use the process of paper chromatography to separate the various pigments in spinach. Drop spinach extract onto a piece of chromatography paper. Let dry and repeat 4 times in order to get a concentrated amount of extract. Have instructor add solvent to the large chromatography tube. Place paper in tube, put stopper in place and put tube in dark place for 20 minutes. Remove paper and look at record the colors you see. http://www.phschool.com/science/biology_place/labbench/lab4/intro.html

9. Starch Distribution See demo Coleus leaves were tested for the presence of starch using the iodine test. Compare the production of starch in leaves that have been covered with foil for several days and in uncovered leaves. Where is starch stored?

10. 10.5 Chloroplast structure Study the sketch in lab book AND the chloroplast model! Know these locations in the chloroplast: –Thylakoid –Granum –Outer membrane –Inner membrane –Stroma –Where light reactions occur –Where chlorophyll molecules are located