You have been given a plant sample and asked to identify a specific tissue. Upon investigation, you find the cells are all long in length and some of them have small pores. They all contain fluid. You test the fluid using various biochemical tests and discover the fluid contains an abundance of disaccharides. What type of tissue are you looking at?

Question

A.  xylem
B.  phloem
C.  root hair cells
D.  sclerenchyma
E.  meristematic

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 cellular compostition of different types of plant cells? 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

Answer 1

B.  phloem

Clarify Question
· What is the key concept addressed by the question?
        o Plant tissues can be identified by looking at their cellular composition.
· What type of thinking is required?
        o You must apply what you know about plant tissues to identify an unknown sample.
· What key words does the question contain and what do they mean?
        o Biochemical tests, which include tests that can be used to detect macromolecules such as carbohydrates, proteins, lipids, etc.
        o Monosaccharides, which are carbohydrates that are composed of one sugar building block.

Gather Content
· What do you already know about the cellular compostition of different types of plant cells? How does it relate to the question?
        o Glucose, a product of photosynthesis, is a monosaccharide.
        o Phloem transports nutrients, including monosaccharides.
        o Phloem cells are long and have small pores.

Consider Possibilities
· What other information is related to the question? Which information is most useful?
        o Xylem transports water.
        o Root hair cells are tubular and occur just behind the roots.
        o Sclerenchyma cells have tough, thick walls.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The abundance of monosaccharides is an important clue to the identification of this phloem tissue.  Also, the physical characteristics noted in the question are only found in phloem.

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where
 
· Apply level:
o This question asked you to deduce an unknown tissue type.  Answering this question correctly depended on your ability to use known characteristics of 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 phloem carries monosaccharides, or that phloem cells tend to be long with small pores? Did you have trouble extending the characteristics of the tissues to determine the correct answer?