Your lab instructor hands you a root slide and asks you to show her a cell with condensed chromosomes arranged in a straight line. In which section of the root would you begin your search?

Question

A.  It doesn't matter, all zones have the same level of mitotic activity.
B.  zone of elongation
C.  zone of maturation
D.  zone of cell division
E.  root cap

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 appearance of root cells in the different zones? 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.  zone of cell division

Clarify Question
· What is the key concept addressed by the question?
        o The cellular activities of the root zones.
· What type of thinking is required?
        o You must apply what you know about the nature of a root to identify the location of the process at hand.
· What key words does the question contain and what do they mean?
        o Root tip, which is an area of active growth and cell division.

Gather Content
· What do you already know about the appearance of root cells in the different zones? How does it relate to the question?
        o The zone of cell division in a plant root is a site of active mitosis.  
        o Students often use slides from this zone to examine all of the mitotic phases.
        o Chromosomes are visible using a light microscope during mitosis.

Consider Possibilities
· What other information is related to the question? Which information is most useful?
        o Zone of maturation contains cells that differentiate.
        o Zone of elongation contains cells that elongate via the merging of small vacuoles.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o You need to connect the zone of cell division to the highest amount of mitosis.Abundant mitosis would provide the best opportunity to view condensed chromosomes that are in a straight line, as they would be in mitotic metaphase.  You can rule out options that include functions not covered by the zone of cell division.

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 differentiate the roles of the zones in a root tip.  Answering this question correctly depended on your ability to use your knowledge of each zone 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 the zone of cell division has active mitosis, or that chromosomes condense and are visible during mitosis? Did you have trouble extending
the functions of each zone to determine the correct answer?