NAME ________________________________ DATE_____________ PD_______ #_______
Online Photosynthesis Lab
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Directions: Go to the following URL and answer the questions below USING COMPLETE
SENTENCES IN ALL OF YOUR ANSWERS and show your answers in Red Font
http://www.phschool.com/science/biology_place/labbench/lab4/intro.html
Read Plant Pigments and Photosynthesis
Introduction
1. What is photosynthesis? (1pt.)
2. What kind of organisms does photosynthesis occur in? (1pt.)
3. What is the primary photosynthetic pigment in chloroplasts? (1pt.)
Push “NEXT” and Read Key Concepts I: Plant Pigment Chromatography
4. What is Paper chromatography? (1pt.)
5. Why do the molecules migrate up the paper at different rates? (1pt.)
6. How is paper chromatography useful? Critical thinking (Hint use your brain to answer this one)
(1pt.)
Push “NEXT” and Read Design of the Experiment I
7. How do you separate the pigments of found in chloroplasts? (1pt.)
Push “A CLOSER LOOK” and Read Depositing the Pigment
8. How do you get the plant pigment to be deposited on the chromatography paper? (1pt.)
Push “NEXT” and Watch Pigment Separation (time-lapse view)
9. After watching the paper chromatography animation then describe the relative migration of the
different pigment molecules. (i.e.- what pigment migrated the furthest, 2nd furthest, etc.) (1pt.)
Push “NEXT” and Read Analysis of Results I
10. Describe what the Rf (Reference front) measures. (1pt.)
11. Write the formula used to calculate the Rf value. (1pt.)
12. Solve the Rf value of for the green pigment from the Black ink chromatogram (SHOW your
WORK). (1pt.)
Push “Self Quiz” and take the quiz Lab Quiz I
13. Take the Self Quiz and write the correct answers along with the reason that they are correct.
(3pts.)
Question 1
Question 2
Question 3
Push “NEXT” and Read Key Concepts II:
14. What happens to electrons of the plant pigment molecules in the “Light dependent reactions” of
photosynthesis when they are exposed to light? (1pt.)
15. Define: Thylakoid- (1pt.)
16. When the electron acceptors of the thylakoid membrane accept the excited/high energy electrons
what are they then used for? (1pt.)
Push “NEXT” and Read Using DPIP As an Electron Acceptor
17. What color is DPIP before it is reduced from accepting electrons? (1pt.)
18. What happens to DPIP when it is reduced? (1pt.)
19. For this lab the natural electron acceptor molecules are mechanically disrupted and when light
strikes the pigment molecules of a thylakoid membrane inside of a chloroplast where do the
electrons go? (1pt.)
20. In this experiment the chloroplast will be in a DPIP solution and the amount of light that can pass
through the solution will increase as the DPIP is reduced and turns colorless. Even if all of the
DPIP is reduced not all of the light will pass through the solution. Why not? Critical thinking
(Hint use your brain to answer this one) (1pt.)
21. What is the instrument called that is used to measure the amount of light absorbed by the
solution or the amount of light that passes through the solution? (1pt.)
Push “NEXT CONCEPT” and Read The Spectrophotometer
22. Perform a search to determine the definition of transmittance- (1pt.)
23. What color is a 605nm wavelength of light? (1pt.)
24. If DPIP is blue why do we want to shine a 605nm wavelength of light through our sample?
Critical thinking (Hint use your brain and some extra research to answer this one) (1pt.)
25. How is the amount of DPIP decreased in the sample? (1pt.)
26. Why do you want to calibrate the spectrophotometer by first setting the transmission to 0% with
an empty sample chamber and then by setting the transmittance to 100% with a tube containing
the solvent minus DPIP? Critical thinking (Hint use your brain to answer this one) (1pt.)
Push “NEXT” and Read Design of the Experiment II
27. What range of light do plant pigments absorb? (1pt.)
28. List the contents of the four test tubes for this experiment (4pts.)
Tube 1Tube 2Tube 3Tube 4-
29. What is going to happen in tube 3 that is wrapped with foil? Critical thinking (Hint use your
brain to answer this one) (1pt.)
30. Give one word for what will happen to the molecules of the chloroplasts when they are boiled
that are used in tube 4? (Hint: what happens to proteins when they are exposed to high
temperatures?) (1pt.)
Push “NEXT” and Read Analysis of Results II
31. Based on your understanding of the light reactions of photosynthesis, draw
on top of the graphs using the “lines and connectors” drawing tool under
“insert shape” to predict the approximate shapes of the curves. (3pts.)
Push “Self Quiz” and take the quiz Lab Quiz II
32. Take the Self Quiz and write the correct answers along with the reason that they are correct.
(5pts.)
Question 1
Question 2
Question 3
Question 4
Question 5