Question

The Mystery Cell contains water, dextrose, and hemoglobin. At equilibrium, the Mystery Cell contains 180 molecules, the extracellular fluid contains 360 molecules, and the membrane position is approximately 13.3.

If you add water permeability to the membrane, you will see that the initial composition of the extracellular fluid is not isotonic to the SimCell.

You want to know the concentration of solutes inside the Mystery Cell (at equilibrium), and you want to know how much of the solute is hemoglobin.

1. First, what is the approximate concentration of solute molecules in the mystery RBC at equilibrium? Explain how you determined this value. [Hint: if all solute molecules have the same effect on pressure, you don’t need to experiment with both solutes to answer this question correctly.]

Answer 1

The starting position of the membrane was 13.3. The position of the membrane alters when it is made permeable to water as the initial composition of the extracellular fluid doesn't remain isotonic to the SimCell.

So, in this the aim is to know the concentration of solutes inside the mystery cell at equilibrium. The calculations for the initial concentrations of dextrose and other solutes are the following: 20/ (200 + 30 + 20)= 20/250= 0.08 x (100)= 8% [Glucose]; 50/(200+30+20)= 50/250= 0.2 x (100)= 20% [Total solute]. The concentration of water in the SimCell is 80%. Total solutes: 50/250= .2 x (100)= 20% [only dextrose]; total water: 200/250=.8 x (100)= 80%.

Given:- There are 180 molecules in the mystery cell and 360 molecules are present in the extracellular fluid. The concentration percent of the solute in the RBC is: 60/180= .333 x (100)= 33.3%. The concentration percent of solute in the extracellular fluid is: 60/360= .167 x (100)= 16.7%: It is predicted that the RBC will expand as the water would diffuse into the cell. Because the extracellular fluid is hypotonic to the RBC, the RBC will grow.

The amount of dextrose and hemoglobin needed to make an isotonic solution for the cell is: 120/180= .666 x (100)= 66.7%. total water: 60/180= 33.3%; wholly making 100%.