Question

Pre Lab 5 - Question 5

5. A group of researchers are interested in a question about the osmolarity of the cells of a particular plant species. The team prepared slabs of tissue of this organism and measured the volumes of these tissue slabs. Then, the slabs were submerged in their own solutions of varying sucrose concentrations. After two hours, the slabs were removed from the sucrose solutions, and the percent difference in volume of the slabs was calculated and graphed. The researchers included on the graph a "best fit" line of the data, shown in red here: 15.00 10.00 5.00 0.00 0.3 Msučros 0.4 M sucrose OM sucrose 0.1 M sucrose 0.2 M sucrose 0.5 M sucrose 0.6 M sucrose -5.00 -10.00 -15.00 20.00 Percent Difference Linear (Percent Difference) A positive percent difference indicates an increase in volume of the cells; a negative percent difference indicates a decrease in the volume of the cells. Based on these findings, the osmolarity of the cells of the plant is approximately ?_ M. Enter answer...

Answer 1

It is given, positive percent difference indicates an increase in cell volume. The movement of water is from a lower solute concentration to a higher solute concentration. Which means cell's osmolarity is higher for all positive percent difference and it us lower for all negative percent difference.

From the figure, between 0.2M and 0.3 M sucrose, the cell's osmolarity is isotonic ( passing through the origin) . Then the cell's osmolarity must be approximately 0.25 M.