You have been assigned the task of identifying the cells in a plant tissue sample. Using your microscope you determine the cells are living and their cell walls vary in thickness. Upon further observation you note that the cells are arranged in strands just below the epidermal surface. What cell type do you determine the cells to be?

Question

A.  Collenchyma
B.  Parenchyma
C.  Sclerenchyma
D.  Sieve elements
E.  Tracheids

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 characteristics of plant cells as viewed through a microscope? 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

A.  Collenchyma

Clarify Question
· What is the key concept addressed by the question?
        o Plant cells can be identified by examining its microscopic characteristics.
· What type of thinking is required?
        o Apply, because you must remember what you know about plant cells, and then apply it to an unknown sample.
· What key words does the question contain and what do they mean?
        o Strands, which refers to a long growth pattern of cells in tissue.
        o Epidermal surface, which refers to the tissue that covers the plant body.

Gather Content
· What do you already know about  the characteristics of plant cells as viewed through a microscope? 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 have thin walls and are initially spherical.
        o Sclerenchyma have tough, thick walls.
        o Tracheids are dead, hollow cells.
        o Sieve elements are narrow and stacked

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o When you are presented with an identification question, you must look for identifying characteristics that are possessed by only one of the possible cell types.  Collenchyma cells can be identified by their variable cell wall thickness, and by their tendency to form strands.

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 recognize plant tissues.   Answering this question correctly depended on your ability to use the characteristics of plant tissues  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 cells tend to form strands, or that collenchyma
cells have variable cell wall thickness? Did you have trouble extending plant tissue characteristics to determine the correct answer?