All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The process in which molecules of a substance move from an area of high concentration to areas of low concentration is called Diffusion. Whereas Osmosis is the process in which water crosses membranes from regions of high water concentration to areas with low water concentration. While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help. When the concentration of the environment outside of the cell is lower than the inside of the cell, this is called a hypotonic solution. In hypotonic solutions, when water moves into the cell they burst, which is known as lysis. A hypertonic solution is when the concentration of outside the cell is higher than the inside of the cell. In hypertonic solutions, water moves out of the cell, making the cell lose water and shrink; this is called crenation. An isotonic solution is when the concentration of dissolved molecules is the same both inside and outside of the cell. Thus there is no net movement. The purpose of this experiment is to investigate whether osmosis occurs across the membrane of potato cells.
The potato that will be more hypertonic to the sucrose solution will gain weight, whereas the potato when hypotonic to the solution will lose weight. When the potato is most isotonic the osmolarity of the potato will be 0.4.
7 250-mL Beakers
Sucrose Solutions: 0.1,0.2,0.3,0.4,0.5,0.6 (M)
Deionized Water (0 molar)
Balance that weighs to the nearest 0.01
To perform this experiment seven 250-mL beakers were obtained, rinsed thoroughly and dried with a paper towel. Next a small...