If normal cells (300 mOsm) are placed in a 0.9% solution of NaCl, their shape is

Question

If normal cells (300 mOsm) are placed in a 0.9% solution of NaCl, their shape is unchanged. Which of the following would you expect to be true? The correct answer is C but I dont understand why the rest are wrong, Please Explain! Thanks :)

A. Placing the cells in a 1.0% NaCl solution would cause lysis.

B. Placing the cells in a 0.5% MgSO4 solution would cause crenation.

C. Placing the cells in a 0.9% solution of glucose would cause lysis. (glucose does not dissociate)

D. Placing the cells in a 0.9% solution of glucose would cause crenation.

E. None of these are true.

Explanation / Answer

Answer and Explanation .

If cell is in Hypotonic environment, i.e. its inside solute concentration is more to outside,
Then, water will flow from Cell to outside.
Resulting in Lysis.

If cell is in Hypertonic environment, i.e. its inside solute concentration is less to outside,
Then, water will flow into Cell from outside.
Resulting in Crenation.

Now, Given,
Cell is Isotonic to 0.9% NaCl
Isotonic, i.e, it is in Equilibrium state,
and water will not flow

So, that means,
if NaCl concentration > 0.9 % = will cause Crenation.
< 0.9 % = will cause Lysis.
So, now
Reasons for the Options Given,

A. 1 % NaCl will cause Crenation. Therefore Wrong.
B. 0.5 % of MgSO4 concentration is less to concentration inside. It should cause Lysis not Crenation. Therefore, Wrong.
C. 0.9 % of Glucsose concentration is less to Concentration Inside.
Therefore, Water will flow in and cause Lysis.
Therefore, Right Option.
D. 0.9 % of Glucsose concentration is less to Concentration Inside.
Therefore, Water will flow in and cause Lysis.
And not Crenation. Therefore, Wrong.

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