Osmosis Lab
Background:
Sucrose also known as Table Sugar is present in many natural foods and added to many foods today. Human Red Blood Cells, at 0% sucrose concentration, are hypotonic to much of the sugar concentrations of other foods. Observe the table below to understand the concentration of sucrose in some common foods.
Bread - 11% Sucrose
Non-Fat Yogurt - 18% Sucrose
Red Delicous Apple - 11-15% Sucrose
Mountain Dew 12% Sucrose
Osmosis is the movement of a solvent across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
The water (the solvent) can move across the membrane but the dissolved sucrose cannot.
In such situations, water will move across the membrane to balance the concentration of the solutes on both sides. Cells tend to lose water (their solvent) in hypertonic environments (where there are more solutes outside than inside the cell) and gain water in hypotonic environments (where there are fewer solutes outside than inside the cell). When solute concentrations are the same on both sides of the cell, there is no net water movement, and the cell is said to be in an isotonic environment.
In this lab we will test samples of potato or carrot tissue to see how much water they absorb or release in sucrose solutions of varying concentrations. This gives us an indirect way to measure the osmotic concentration within living cells.
Hypo=under, iso=equal, hyper=over
Problem/Purpose: What is the concentration of sucrose in a potato/carrot cell?