Table of ContentsPurposeMaterialsMethodDiscussionConclusionCells have been loosely defined as the building blocks of all living things. All cells are contained by cell membranes, which provide structure to the cell (Cooper. G, 2000). The cell membrane is a semi-permeable membrane that surrounds the cytoplasm of a cell and is made up of a phospholipid bilayer (Cell Membrane, 2014). Cellular diffusion occurs across the cell membrane as a means of transport for substances entering and exiting the cell (Nave R, n.d.). Cell Diffusion According to the Biology Corner, diffusion is the process by which molecules diffuse from areas of high concentration to areas of low concentration (2012). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay There are three main types of cell spreading, these are; simple, channeled and facilitated. Simple diffusion occurs when a particle with a neutral charge and a size small enough to pass through the phospholipid layer passes through the membrane. The molecule must also be hydrophobic, so that the protein can move to the outer side of the membrane without being "repelled" as hydrophilic molecules are. Channel diffusion is a passive transport process in which molecules that do not meet the requirements for simple diffusion use protein channels to pass through the cell membrane. The process of facilitated diffusion requires carrier proteins to move molecules from one side of the membrane to the other (Diffusion, n.d.). Osmosis is the diffusion of water across the cell membrane from areas of lower solute concentration to areas of higher solute concentration (Khan, 2010). “In terms of osmosis, solute refers to all the molecules or ions dissolved in water (the solvent)” (American Society for Microbiology, 2013). Osmoregulation is related to osmosis, as it prevents body fluids from becoming too diluted or concentrated. When the osmotic pressure of a solution is high, the greater the amount of water present that wants to enter that solution (Rybicki, 2009). A hypotonic solution is when the concentration of the solute is lower than that of the outer side of the cell membrane. This is the opposite for hypertonic (All Nurses, 2011). Animals and plants are multicellular and are specialized in their functions and roles in the body or organism. Cells in animals can have roles such as carrying oxygen around the body, and in plants they absorb sunlight, water and materials to carry out processes such as photosynthesis (BBC, 2014). This is the same in humans, as the cells in the body are specialized and each plays its own role. Since a fish contains body fluids and is always surrounded by a fluid environment, it uses the process of osmoregulation to maintain a balance between salt and fresh water in the fish's body. Osmoregulation is also related to osmotic pressure, as this pressure prevents osmosis from occurring in a specific solution when it is separated from the solvent by a semipermeable membrane (Duxbury, 2012). Purpose The purpose of this experiment is to demonstrate the changes in effect in The environment has an osmosis through a semipermeable membrane. Hypothesis: It is hypothesized that distilled water must flow into the beakers and dialysis tubes containing the salt saline solutions to dilute the solute due to osmoregulation (Saladin, 2000). It is also expected that when the solutions are isotonic, the weights should be recurrent (Innovateus, 2006). Materials 4 glasses of 100 ml 4 tubes fordialysis 4 rubber bands Marker Distilled water Salt Method 500 ml of distilled water was placed in a glass and 17.5 grams of salt was added measured on an electronic scale and added. It was stirred until the salt dissolved to create a salt solution to act as the salt water for the experiment. Another 500 mL of distilled water was placed in a separate beaker to serve as fresh water for the experiment. 4The clear dialysis tubes were tied with a knot at one end. 2 dialysis tubes were filled with approximately 10 grams of distilled water and 2 with salt water, then they were weighed on electronic scales and the weight was recorded. The dialysis tubing was placed in 4 smaller containers, 2 containing salt water and 2 with distilled water, with rubber bands holding them in place. One tube of saline and one fresh tube were placed in the beakers with the saline solution and the remaining tubes were placed in the beakers of distilled water. After 48 hours the dialysis tubes were weighed and compared to the original recordings to measure the rate of osmosis that occurred through the dialysis tube. The variables that occurred while conducting the osmosis practice exam and the limitations of these errors/variables. Discussion The Purpose The purpose of this experiment was to demonstrate the effect that environmental changes have on osmosis across a semipermeable membrane. To demonstrate this, the different environments used were saline and distilled water to represent fresh and salt water environments. A dialysis tube was used to represent a semipermeable membrane through which osmosis could occur. Distilled water was hypothesized to flow into the beakers and dialysis tubes containing the salt saline solutions to dilute the solute due to osmoregulation. The results showed that the dialysis glasses and tubes for each of the experiments lost weight. These results contradict research performed before this experiment was conducted. However, these results are likely to be unreliable due to errors in conducting the experiment or unexpected factors such as evaporation. This includes water spilling onto the scales during measurements and water spilling when containers were transported from the practice bench to another bench for examination. Additionally, when dialysis tubes were weighed, they had to be held high so that the water did not escape, and this could have resulted in the weight of the hand holding the tube being measured or the tube being held too high, resulting in less weight to record. This experiment could have been improved by carefully handling the glasses during transportation and when they were placed on the electronic scale to be weighed. When the dialysis tubing was weighed, the other end could be tied off, eliminating the need to hold the dialysis tubing and record the additional or decreased weight. Another limitation to this experiment was that the experiment could only be checked in the next biology theory lesson, and this meant that it was not possible to choose the period of time during which the experiment would remain. The amount of time was also not measured or recorded. This could have been avoided by predicting the remaining time of the experiment and measuring it with a stopwatch. Due to these limitations, the experiment results could have been tampered with during the experiment process. So, even if the results contradict the hypothesis, it is likely that if the experiment were repeated, considering the mentioned adjustments, the results would be different. Further research should be undertaken to see if the hypothesis holds.