Biology Lab: Photosynthesis

Question 1

What is the procedure for photosynthesis?

Answer 1

1. Obtain a large test tube and 1 cm of solvent. Place a stopper and seal
2. Cut a piece of chromatography paper in an arrow like shape to reach the solvent and draw a line with pencil 1.5 cm above the point
3. Use a quarter to extract pigment from spinach leaf and place a section the lead on top of the pencil line.
4. Place the paper in the cylinder so that arrow is barely immersed in the solvent
5. When the solvent reached about 1 cm from the top of the paper, remove the paper and mark the location
6. Mark the bottom of each band and measure the distance.

Question 2

What is the procedure for the chlorophyll fluorescence?

Answer 2

1. Place one 1 spinach leaf in mortar
2. Add 2 squirts of 70% isopropyl alcohol
3. Grind the leaf to release chlorophyll
4. Use a transfer pipette to add a few squirts of chlorophyll extract into each tube
5. With lights on the chlorophyll is a greenish color
6. Grab a UV lamp and cardboard box
7. Shine the lamp
8. The chlorophyll under the lamp should be magenta

Question 3

What is the protocol for absorbance spectrum for plant pigments?

Answer 3

1. Use a transfer pipette and fill a cuvette halfway with the chlorophyll
2. Prepare a blank with isopropyl alcohol
3. Turn on spectrophotometer and pick wavelength of RED 675 nm, GREEn 510 nm, BLUE 450 nm
4. Place the control cuvette of alcohol
5. Read the blank (alcohol)
6. Place the chlorophyll cuvette into the spectrometer and read
7. Write the absorbance readings

Question 4

What is the protocol for leaf structure?V

Answer 4

1. View the prepared leaf slides
2. Compare the two types and identify which is the C3 plant and which is the C4

Question 5

What factors are involved in the separation of pigments?

Answer 5

Solvent, chromatography paper, isolated environment(test tube/sealed test tube)

Question 6

Would you expect the Rf value of a pigment to be the same if a different solvent were used?

Answer 6

Yes. The Rf value would be different if a different solvent were to be used because each solvent is different. The solubility and molecular size of each solvent will yield different results.

Question 7

Explain the process of fluorescence?

Answer 7

When a plant pigment absorbs energy from photons, the electrons on the pigment change to excited energy states. When electron return to their normal state, the absorbed energy is released and as another photon. Due to losing some energy as heat the re-emitted photon has less energy and appears as a different color.

Question 8

Which has more energy the UV light on the chlorophyll extract of the light being emitted during the fluorescence?

Answer 8

UV light on extract has the most energy. Some energy is dissipated as heat from fluorescence.

Question 9

Energy cannot be created or destroyed. So where did the rest of the energy go?

Answer 9

As mentioned before, some of the energy dissipates as heat

Question 10

Which 2 colors of light are the best for photosynthesis?

Answer 10

Blue (425-450nm) and Red (600-700nm)

Question 11

Which color is the worst for photosynthesis?

Answer 11

Green/yellow light because reflects the green light but does not absorb it