The Effects of Sucrose on a Semi Permeable Membrane

The effects of sucrose on a semi permeable membrane

A & P lab section 24

Introduction:

The outside covering of a cell is known as the plasma membrane. This membrane has small proteins that allow some molecules to pass through. Membranes are considered semi permeable because they allow only certain types or sizes of molecules to pass through. Osmosis is the passing of water molecules through a semi permeable cell membrane. When osmosis occurs water molecules will move from an area of high concentration to an area of low concentration by a process called simple diffusion. The semi permeable layer of a cell membrane will let water molecules pass through because they are small, but larger molecules are blocked and not absorbed into the membrane. Certain solutions are considered hypotonic because they have a high concentration of molecules that are small enough to pass through the membrane allowing endocytosis to occur. Endocytosis is the process of moving molecules into a cellular membrane. Certain solutions are considered hypertonic because they do not a high concentration of smaller molecules that can pass through the membrane so the molecules inside the cell will actually experience exocytosis. Exocytosis is the process of molecules moving out of the cellular membrane. Certain solutions are considered isotonic because the consentration of molecules that are small enough to pass through the cellular membrane are approximately equal inside and outside the cell. This type of solution does not allow any exocytosis or endocytosis to occur.

This happens inside the cells of the human body. This experiment was done to help give a visual aide to a process that is going on inside our bodies on a microscopic level. In this experiment eggs were soaked in different amounts of sucrose solution and their weights recorded in fifteen minute intervals to determine the effect of the percentage of sucrose on the amount of osmosis. The independent variable of this experiment is the percentage of sucrose in each solution. The dependant variable of this experiment is the weight of the egg which shows the amount of osmosis.

Hypothesis:

The higher the percentage of sucrose in the solution the less endocytosis will take place causing the egg to have less weight.