Diffusion And Diffusion Essay

Diffusion and Osmosis

Substances can only move across a cell membrane by active transport or passive transport. Active transport moves molecules from a low concentration to a high concentration area using the body’s energy. Passive transport moves molecules from a high concentration to a low concentration area without using any energy. Furthermore, the main process of passive transport is diffusion, which involves the movement of dissolved particles through a semi-permeable membrane from that of a high concentration to a low concentration. The tonicity of a cell refers to the concentration of the solution that will determine the direction and extent of diffusion. Diffusion comes in another form called facilitated diffusion/transport, which

Osmosis is also another type of diffusion where water is transferred from a higher concentration to a lower concentration. Osmosis will then come into play when a membrane that differs in solute concentration breaks in two; the water will move from the hypotonic solution to a hypertonic solution. Initially, the hypotonic solution has a lower concentration, and the hypertonic solution has a higher concentration. The water will then continue its journey down its concentration gradient until it reaches equilibrium; that means the water will have the same solute concentration on both sides. When the solute reaches equilibrium on both sides of the semipermeable membrane, the solution then becomes isotonic. Isotonic solutions are when the solute concentration is the same on the inside and outside of the cells, and that is the reason most cells live in the isotonic state. Additionally, a semi-permeable membrane only permits specific substances to enter, usually opening for a solvent but not most solutes. The substances dissolved in a solution are referred to as a solute; and the solvent is the substance that dissolves a solute in a solution. Therefore, the mixture of a solvent and a solute

The materials needed are three small beakers (150 or 250 ml), a potato, a knife to cut the potato into pieces, a ruler to measure the potato, something to weigh the potato pieces, a timer, a calculator, and three solutions: distilled water, 10% sucrose, and 50% sucrose. The point of this experiment is to calculate the percent change in the mass before and after soaking the potato in the three different solutions. Create your own hypothesis before beginning the experiment. My hypothesis is that the potato soaked in water will have a higher mass after soaking, and that the potato soaked in the 10% sucrose and 50% sucrose will remain the same. Make sure to keep up with your measurements since they are needed to determine the mass percent change. The best way to accomplish this is to use the table provided at the end of this sheet to record your results. The first thing you need to cut the potato into three pieces of about two cubic centimeters (cm^3) in length. The second step you need to take is weighing each potato piece and writing down its mass. Next, label the three beakers with the three different solutions used. Then, you need to pour distilled water over one piece of potato, 10% sucrose on another, 50% sucrose on the last piece of potato; each solution needs to be poured on each potato piece until they are completely submerged. After they are submerged: set your timer for an