All organisms are composed of cells (prokaryotes or eukaryotes). Plant cells and animal cells are two different types of eukaryotic cells. Both are also made of cell membranes and vacuoles, but only plant cells involve a cell wall as a supporting structure. Vacuoles are larger in plant cells and result in 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, drive the movement of water across the membrane. Osmosis, water diffusion and a type of passive transport, allows water to move in and out of a cell. Cells control turgor pressure by osmosis. Say no to plagiarism. Get a tailor-made essay on "Why violent video games should not be banned"? Get the original essay The term "hypertonic" is used to describe a solution composed of a greater amount of solutes than the amount of solutes at the inside the cell. This results in plasmolysis of the cell; Plasmolysis occurs when the cell shrinks due to loss of water from the process of osmosis. The term "isotonic" is used to describe a solution composed of an equivalent amount of solutes inside the cell. Onion cells, a type of plant cell, were used to conduct this experiment. When the cells were enlarged and examined carefully, the hypertonic and isotonic solutions brought a very large change to 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 surface area was used as the dependent variable to compare the effects of hypertonic and isotonic solutions on cell size. I hypothesized that if salt water is applied to the onion cell, it will shrink because the solution will be more concentrated than the cell. The salt water and the cell are not equally concentrated. Water will flow out of the cell to balance the amount of solutes in the cell and the solution. A slide and slide cover were used to safely place the onion skin and solutions under the microscope. The microscope was used to visualize the onion skin under 400x magnification. The onion skin was used to compare the areas of the cells after application of the solutions. The control variable, fresh water, and the independent variable, salt water, were used to be applied to the onion cell. The constant laboratory variables were microscope, magnification, cell field diameter, and onion skin. First, the onion skin was placed on the blade. Then a drop of fresh or salt water was applied to the onion skin. The sliding lid was placed over the skin of the onion and helped to hold it in place. Observation: It was more difficult to focus and visualize the onion cell with an isotonic solution under the microscope. The amount of light emitted from the microscope affected the details of the onion skin when viewed. 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 compared. Data showed that salt water and fresh water had a major effect.