4

What happened to the cell to cause it to shrink?

Due to the hypertonic solution, water is leaving the cell.

Why is this called a selectively permeable membrane?

It allows small molecules, such as water, to pass through but not larger molecules, such as those in corn syrup.

How are you going to determine if iodine and/or starch diffuse across the dialysis tubing?

A.In this situation the iodine would diffuse from the beaker into the dialysis tubing with the starch. C.If both starch and iodine are able to diffuse across the dialysis tubing they would mix on both sides of the membrane turning both solutions dark purple.

Why does blood become clear in distilled water?

Because distilled water is hypotonic, the cells have burst and no longer block light passing through the fluid.

What happened to the cell to cause it to swell?

Due to the hypotonic solution, water is entering the cell.

Did diffusion across the membrane occur for the starch solution?

NO

What is happening to the cell since there seems to be no change?

Since the solution is isotonic, there is no net movement of water.

Did diffusion across the membrane occur for the glucose solution?

YES

Did diffusion across the membrane occur for the iodine solution?

YES

Elodea cells

have a rigid cell wall that helps them keep their shape even when water moves into or out of them.

An isotonic environment

is balanced so water enters and leaves cells at the same rate.

A hypertonic environment

tends to cause a cell to shrivel or collapse as water exits the cell.

A hypotonic environment

tends to cause a cell to swell or burst as water enters the cell.