You come across a recipe for rhubarb pie. Never having heard of rhubarb, you do a little research. You find out that the part of a rhubarb plant that people eat is the petiole of a large leaf. You purchase some rhubarb for your pie and notice that it contains many long stringy fibers. Based on your knowledge of plant tissues, you know that the stringy fibers are

Question

A.  parenchyma tissue.
B.  phloem tissue.
C.  sclerenchyma tissue.
D.  collenchyma tissue.
E.  xylem tissue.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

Gather Content
· What do you already know about the characteristics of different plant cell types? 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

D.  collenchyma tissue.

Clarify Question
· What is the key concept addressed by the question?
        o Plant cell types can be differentiated by individual characteristics.
· What type of thinking is required?
        o You must apply what you know about individual cell types to identify an unknown cell type in a sample. · What key words does the question contain and what do they mean?
        o Petiole, which is a stalk on the leaf that attaches it to the stem of a plant.

Gather Content
· What do you already know about the characteristics of different plant cell types? How does it relate to the question?
        o Collenchyma cells have walls of varying thicknesses.
        o Collenchyma cells often form strands.

Consider Possibilities
· What other information is related to the question? Which information is most useful?
        o Parenchyma may have thin cell walls, but it is not stringy.
        o Phloem has long cells with small pores, but it is not stringy.
        o Xylem contains vessels, but is not stringy.
        o Sclerenchyma cells are typically dead at maturity, and is not stringy.

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

        o If you connect the ideas that the unknown cells are from the petiole of the leaf, and that they are stringy, you can only conclude this is collenchyma.  Collenchyma is known for its fibrous, stringy nature.

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?

· Apply level:
        o This question asked you to identify an unknown plant tissue.  Answering this question correctly depended on your ability to use your knowledge of the characteristics of plant tissue in a new situation.   If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you remember that collenchyma is known for its fibrous, stringy nature., or that other tissues are not of this nature? Did you have trouble
extending your knowledge of the characteristics of plant tissue to determine the correct answer?