BIOL 211 Summer 2012 NSCC
Due 7/10/12
Pre-lab 3: Diffusion and Osmosis
Answer the following questions after reading this week’s lab handout, and hand in the
completed worksheet prior to lab.
1.
Consider our experiment in Part 1. In this experiment, we’ll place a starch solution in a
membrane packet (a dialysis slide). The membrane in the packet is a selectively permeable
membrane that allows small molecules to diffuse through, but blocks the passage of larger
molecules. We’ll submerge this membrane in an iodine solution. Based on what you know
about the molecular size of starch (composed of chains of glucose) and iodine, generate a
hypothesis (a tentative explanation) and a prediction (an expected observable result) for this
experiment
Hypothesis:
Prediction:
2.
In Part 2, we’ll use an egg as a model cell to think about osmosis. Consider an egg
placed in a hypertonic solution. Again write a good hypothesis and prediction to describe
this experiment.
Hypothesis:
Prediction: