AP Lab 4: Plant Pigments and Photosynthesis

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AP Lab 4 Plant Pigments and Photosynthesis
Prelab Discussion!
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AP Lab 4 Part A Pigment Chromatography

• What is chromatography?
• A separation technique that separates molecules
  by size and solubility

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AP Lab 4 Part A Pigment Chromatography

• What will our setup look like?

We will substitute a screw-top jar for a
graduated cylinder!
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Part A Chromatography

• Remember to make a dark pigment line!
• Allow pigment to dry between applications.
• Do not allow solvent above pigment line at start!

Be sure to mark solvent line at end for
calculations!
solvent
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AP Lab 4 Part A Pigment Chromatography

• What is Rf and how do you calculate it?
• It is the relationship between the distance moved
  by a pigment and the distance moved by the
  solvent.

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AP Lab 4 Part B Photosynthesis

• How could one measure photosynthetic rates?
• Amount of O2 produced
• Amount of glucose produced
• Amount of ATP produced
• Amount of NADPH created by the reduction
  reaction
• NADP H ? NADPH

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AP Lab 4 Part B Photosynthesis

• We will focus on the NADPH production.
• We know that NADPH is the final electron and H
  receptor in the light dependent reactions.
• We will be substituting the compound DPIP (a blue
  dye to be the final electron acceptor.
• Therefore as photosynthesis progresses, the blue
  dye will become increasingly clear.

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Light Dependent Reactions
DPIP!
http//www.stolaf.edu/people/giannini/flashanimat/
metabolism/photosynthesis.swf
Fig. 7.12a, p. 121
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Glucose made with ATP energy
CO2 reactant
Sun Energy Source
Chlorophyll absorbs solar energy
NADPH drops off H
NADPH
H
H
C
C
O
NADP
H2O reactant
O
O
O
H
H
O2 waste
Light Dependent Rxns Thylakoid Membrane
Light Independent Rxns Stroma
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AP Lab 4 Part B Photosynthesis

• We will measure the absorbance with probeware
  and a colorimeter.
• What would a high absorbance mean reagrding
  photosynthetic rate?
• A low absorbance?

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AP Lab 4 Plant Pigments and Photosynthesis
AP Lab 4 Day 2 Take out your flowcharts and lab
packets.
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Light Dependent Reactions
DPIP!
http//www.stolaf.edu/people/giannini/flashanimat/
metabolism/photosynthesis.swf
Fig. 7.12a, p. 121
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Glucose made with ATP energy
CO2 reactant
Sun Energy Source
Chlorophyll absorbs solar energy
NADPH drops off H
NADPH
H
H
C
C
O
NADP
H2O reactant
O
O
O
H
H
O2 waste
Light Dependent Rxns Thylakoid Membrane
Light Independent Rxns Stroma
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Part B Photosynthesis

• Note setup!

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Part B Photosynthesis

• Troubleshooting Tips
• Calibrate once!
• Two people can calibrate the sensor then help out
  with the cuvette setup!
• Remember to mix each cuvette prior to taking an
  absorbance reading!
• Remember to handle cuvettes by the curved sides
  and load properly!