Photosynthesis Lab Capture of Light Energy Photosynthesis Capture

Photosynthesis Lab: Capture of Light Energy

Photosynthesis: Capture of Light Energy • Recall that white light consists of a continuum of wavelengths (measured in nm) • When you see one color of light, you are seeing one wavelength • If a pigment is illuminated with white light, the color we see is the color most reflected/absorbed by that pigment. • A spectroscope contains a prism, which causes the spectrum to form.

Directions for the Photosynthesis Lab • You will need to have your lab printed and in front of you as well as crayons or colored pencils. • Read the introductory paragraphs under experiments 9. 5 and 9. 6. You will need to know what an absorption spectrum and transmission spectrum are. Read the short paragraph about how a spectroscope works (towards the bottom on pg. 123) • Once you understand that a spectroscope has a prism inside of it and that you can pass white light through a prism and it will separate white light into its component wavelengths (colors). Example: If white light is passed through a prism then through a purple filter, we should only see purple light being transmitted through the filter, where all other colors are being absorbed (and therefore not seen). 1. Complete question 1 by coloring in the spectrum of white light on figure 9 -4. Use your textbook, power point lecture or other resource to correctly color in the grid. 2. For question 2, list the colors that you expect to be absorbed when white light is passed through a prism and then through a red, blue and green filter respectively. • You should find that from these experiments, that the color of the filter (the color you can see) is the color of light that is not being absorbed by that filter. So if you are passing white light through a prism and then a through a purple filter, it will transmit the color purple and absorb red, orange, yellow, green, and blue. This is what it is asking when it says to “make a general statement concerning the color of a pigment (filter) and the absorption of light by that pigment” at the top of pg. 124). 3. For question 4 can you guess what colors of light would be transmitted by a chloroplast extract, that has green, yellow, orange and red pigments (chlorophyll a, b and carotenoids respectively)? If so, color them in the grid on figure 9 -5 4. The only other part I want you to complete is the labeling of the chloroplast (pg. 126) • The structures you need to label are below the image. In addition to the structures it asks you to label, I want you to add, granum and, label where the Light reactions and Calvin Cycle occur in the chloroplast. 5. Bring this with you to lab next week and I will help you fill in and understand the information that you will be tested on for your lab midterm. 6. For your quiz in lab next week, you can look at the pre-lab questions for a guide. Do not worry about any questions in the pre-lab that relate to a part of the lab that you have not completed.