All organisms are composed of cells (prokaryotic or eukaryotic). Plant cells and animal cells are two different types of eukaryotic cells. Both are similarly made up of cell membranes and vacuoles, but only plant cells involve a cell wall as a support structure. Vacuoles are larger in plant cells and cause turgor pressure when water is moved from outside the cell [low solute concentration] into a vacuole [high solute concentration]. Cell membranes are composed of phospholipid bilayers. Aquaporins are found in the cell membrane; these passive transporters, or proteins, conduct the movement of water across the membrane. Osmosis, the diffusion of water and a type of passive transport, allows water to move in and out of a cell. Cells control turgor pressure through osmosis. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay The term “hypertonic” is used to describe a solution composed of a greater amount of solutes than the amount of solutes inside the cell. This results in plasimolysis of the cell; plasimolysis occurs when the cell shrinks due to the loss of water through the process of osmosis. The term “isotonic” is used to describe a solution composed of the equivalent amount of solutes present within the cell. Onion cells, a type of plant cell, were used to conduct this experiment. When the cells were enlarged and observed carefully, the hypertonic and isotonic solutions made a large change on the cells. The hypertonic solution [salt water] was used as the independent variable, while the isotonic solution [fresh water] was used as the control. variable. Cell area was used as a dependent variable to compare the effects of hypertonic and isotonic solution on cell size. I hypothesized that if you apply salt water to the onion cell, the onion cell will shrink because the solution will be more concentrated than the cell. The salt water and the cell are not equally concentrated. Water will move out of the cell to balance the amount of solutes in the cell and in the solution. A glass slide and lid were used to safely place the onion peel and solutions under the microscope. The microscope was used to view the onion peel at 400x magnification. Onion peel was used to compare cell areas after application of the solutions. The control variable, fresh water, and the independent variable, salt water, were used for the onion cell application. The constant laboratory variables were the microscope, magnification, cell field diameter, and onion skin. First, the onion peel was placed on the slide. Then, a drop of fresh or salt water was applied to the onion peel. The slide lid was placed over the onion skin and helped secure it in place. Observation: It was more difficult to focus and visualize the onion cell with the isotonic solution under the microscope. The amount of light coming from the microscope affected the details of the onion skin when it was observed. When the cells were magnified 400x, the microscope was blurry and took time to adjust. The hypothesis was supported by the data as shown in Figure 2. After conducting the experiment, the data was.