1. Photosynthesis Intro
Chapter 8

2. What you need to know!
How photosystems convert solar energy into chemical energy

3. Chloroplasts

4. Thylakoid Membrane has
Pigment Molecules imbedded within Photosystems 1 & 2
Chlorophyll a, b, carotenoids, and xanthophylls
Electron transport chain molecules
ATP Synthase

5. Structure of Chlorophyll
Expensive molecule: is recycled in fall in temperate climates
Magnesium center
Chlorophyll has a hydrocarbon tail to make it lipophilic for membrane attachment

6. Physics of Light Light (like all radiation) has energy
Radiation can be sorted into an electromagnetic wave spectrum according to its wavelength
ROY G BIV

7. Chlorophyll Absorbance
Chlorophyll a and b absorbance spectrums for both pigments maximize absorbance in the…
What light is reflected?

8. Leaf Structure and Photosynthesis
Photosynthesis takes place in the mesophyll
CO2, O2, & H2O (water vapor) will diffuse through stomata
Stomata must be open for photosynthesis
Only turgid stomata cells are open; if they become flaccid, they close
Cuticle
Mesophyll
Vein
Cuticle
Stoma
(stomata = plural)

9. Paper Chromatography
Technique for separating and identifying pigments from cell extracts.
The solvent moves up chromatography paper by capillary action
Pigments (solutes) are dissolved in the solvent and are carried up the paper

10. Paper Chromatography Differing pigments have different properties:
Solubility, size/shape, polarity
Different bands form as the solutes separate while they migrate up the paper

11. Rf Values of Pigments
Rf is a ratio of the migration of the pigment (B) over the migration of the solvent (F)
Rf = B/F
B = distance (mm) from the bottom of the pigment origin to the bottom of the pigment migration
If more than one pigment molecule is tested the highest band is B1, the next band is B2, etc.
F = distance from the bottom of the pigment origin to the bottom of the solvent front

12. Rf Values of Pigments Solvent Front B4
Band #
Distance migrated
Rf value
Identification of substance 1 2 B4
Rf values of substances are specific to the chromatography system used. If paper or solvent is changed, Rf values change
Rf values do not change with migration length in a system
Rf values are always between 0 & 1 B3 B2 B1
Pigment Origin