Plants maintain higher levels of phytochrome at their growing tips where phytochrome plays important roles in growth responses to light. Phytochrome levels are also high in areas of the plant that are "greening". What does this suggest about the role of phytochrome in these "greening" zones?

Question

A.  Phytochrome is absorbing green wavelengths of light.
B.  In these areas, phytochrome is the first step in the electron transport chain of photosynthesis.
C.  Phytochrome is facilitating the transcription and translation of photosynthesis related proteins.
D.  Phytochrome is facilitating the migration of chlorophyll pigments from other areas of the plant.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
        · What key words does the question contain and what do they mean?

Gather Content
· What do you already know about the role of phytochrome in plants? How does it relate to the question?

Consider Possibilities
· What other information is related to the question? Which information is most useful?

Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?  

Answer 1

C.  Phytochrome is facilitating the transcription and translation of photosynthesis related proteins.

Clarify Question
· What is the key concept addressed by the question?
        o This question is asking about the role of phytochrome in plants.
· What type of thinking is required?
        o This question is asking you to evaluate-the importance of phytochrome. · What key words does the question contain and what do they mean?
        o Phytochrome, which is a pigment-containing protein.

Gather Content
· What do you already know about the role of phytochrome in plants? How does it relate to the question?
        o Phytochrome transduces information.
        o One of the functions of phytochrome is to activate the transcription of light-regulated genes.

Consider Possibilities
· What other information is related to the question? Which information is most useful?
        o If phytochrome absorbed green wavelengths of light, the tissue in which it occurred would not appear green.
        o Phytochrome does not play a direct role in the reactions of photosynthesis.

Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o To answer this question, you must connect phytochromes with the indirect role that they play in photosynthesis.  Phytochrome activates the expression of genes that code for photosynthesis-related proteins like the proteins necessary for chloroplast development.

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result? · Evaluate level:
This question asked you to evaluate the function of phytochromes.  Answering this question correctly depended on your ability to evaluate the activities that occur in tissue that has phytochromes present. If you got the correct answer, well done! If you got an incorrect answer, where did the process break down? Did you remember that phytochromes play an indirect role in photosynthesis? Did you have trouble weighing the merits of the presence of phytochromes to determine the correct answer?