Lisa
July 1, 2013
Purpose
To use the properties of diffusion and osmosis to see the effects of either corn syrup or water on a shell-less raw egg over a three day period. While looking to see the effects of these liquids on the raw egg, one can also apply the properties of hypotonic, hypertonic, and isotonic solutions.
Introduction
Cells have an outer covering called the cell membrane. The membrane is selectively permeable meaning that it has tiny pores or holes that allow objects to move across it. The cell membrane controls what moves in and out of the cell. Food and oxygen move into cells across the cell membrane through the process of diffusion. Diffusion is the process by which molecules spread from an area of higher concentration to an area of lower concentration. Diffusion will continue until it reaches equilibrium. “Equilibrium” meaning that both sides of the membrane have an equal concentration. Osmosis is a special type of diffusion where water moves across a membrane and go to a higher concentration of solute (lower concentration of water) from the lower concentration of solute.
Both diffusion and osmosis work with the concentration gradient. In osmosis, water can travel in three different ways. If the molecules outside of the cell are lower than the concentration in the cytosol, the solution is said to by hypotonic to the cytosol, in this process, water diffuses into the cell until the cell is once again at an equilibrium. If the molecules outside of the cell are higher than the concentration in the cytosol, the solution is said to be hypertonic to the cytosol, and water diffuses out until equilibrium exists. If the molecules outside of the cell are equal then it is isotonic to the cytosol and there is no net movement of water.
In my experiment, a shell-less egg was used that was surrounded by vinegar. The membrane was left intact on
References: Enger. E., Ross, F. & Bailey, D. (2012). Concepts in Biology 14th Edition. New York, New York: McGraw-Hill. Print.