A research laboratory is attempting to collect the content of human red blood cells. The type of solution researchers should use to cause blood cells to lyse (burst) would be

Question

A.  hyperosmotic.
B.  isosmotic.
C.  hypoosmotic.
D.  osmotic.

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 know about osmotic concentration? 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.  hypoosmotic.

Clarify Question
· What is the key concept addressed by the question?
     o The question asks about osmotic concentration.
· What type of thinking is required?
     o You are being asked to apply your knowledge of osmotic concentration to choose what solution would cause a red blood cell to lyse.
· What key words does the question contain and what do they mean?
     o Type of solution – the question is specifically asking about the osmotic concentration of the solution.
     o Cell lysis – this requires enough water to enter the cell to cause it to swell until it bursts.

Gather Content
· What do you know about osmotic concentration? How does it relate to the question?
     o Hyperosmotic solutions would contain more salt than the cells, hyper is the root for more.
     o Hypoosmotic solutions would contain less salt than the cells, hypo is the root for less.
     o Isoosmotic solutions would contain the same salt concentration as the cells, iso is the root for same.

Consider Possibilities
· What other information is related to the question? Which information is most useful?
     o Water moves across membranes by osmosis. Water will move from an area of lower salt concentration to an area of higher salt concentration until the salt concentration on both sides is equal.

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 want red blood cells to swell, you want water to move into the blood cells. For this to happen the cells need to have more salt inside them than the surrounding solution. The solution would then be hypo osmotic relative to the cells, and contain less salt than the cells.

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?
     o This question asked you to apply the definition of osmotic concentration to determine what type of solution would cause a red blood cell to lyse. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you recall that for a cell to swell up it would need to be in a solution with a lower salt concentration than the inside of the cell? Did you remember what the roots hyper, hypo and iso mean? Did you understand that in osmosis water moves from an area of lower salt to higher salt?