?Cell Membrane Transport Lab Report Essay
Cells are the most significant building blocks of all living things. They are also the tiniest living organisms in the human body which provides structure for the body and intake nutrients that become energy. Cell membranes control what goes in and out the cell, it protects it. The lipid bilayer describes the membrane of both animal and plant cells where the properties that make up phospholipids are very important to the cell membrane function, it has protein which is dispersed properly and it mainly functions in the selective transport of molecules both in and out of the cell. Just like transport of many molecules and water are very vital processes for many living organisms.
There is active and passive transport; active transport includes functions of a cell membrane to selectively push specific types of molecules across the membrane and there is passive transport in which it does not have need of an active role for the membrane. Osmosis and dialysis are also occasionally called passive transports because they too do not require an active role for the membrane. Osmosis is movement of water across a semipermeable membrane of low concentration to a solution of high concentration. On the other hand diffusion is movement of molecules from a high concentration to a low concentration. Osmosis is a form of diffusion but a distinction would be that it deals essentially with water. Tonicity is what makes the cells either shrink or grow depending on the environment it is placed at, it is an osmotic pressure and it is influenced by the different concentrations of solutes in and out of the cell. Filtration is what is used to remove solid particles and they can be removed by passing through a liquid and gas. The information above is very important because it is exactly what everything in this lab will be about. It explains in detail what every single little definition and important information means. It is relevant to what the lab is trying to describe and the human body needs it in order to function the way it supposed to. Osmosis helps by the cells not dying, if a cell has too much water osmosis will occur and will withdraw some of it to keep it from overflowing and vice versa if it’s hypertonic it
will move some water in to keep it from shriveling up.
Filtration helps the body by filtering blood vessels and refunding clean blood into the body and exerting harmful substances in water and later on urine. There are five experiments that are going to be tested which are Experiment one, two, three, four and five. Experiment one deals with osmosis and biochemical testing, the independent variable for osmosis will be the tonicity and the dependent variable is the cell mass. Experiment two, three, four all have to do with diffusion; Experiment two is diffusion of gel in which the independent variable is particle size or temperature and the dependent variable is the diffusion rate. Experiment three is looking for the diffusion of air its independent variable is the distance and the dependent variable is also the diffusion rate. Experiment four is testing diffusion in a liquid and the independent variable is temperature and the dependent variable is the same as experiment one and two which is the diffusion rate. And experiment five is testing filtration its independent variable is time and its dependent variable is filtration rate. It is hypothesized that tonicity will affect osmosis by either making osmosis go at a high speed or low speed. It is hypothesized that the rate of diffusion will be fast in room temperature rather than in cold temperature. It is hypothesis that the rate of diffusion will vary with the state of matter. It is hypothesized that the bigger the particle the slower diffusion will happen throughout a selectively permeable membrane. It is hypothesized that the farther the distance the longer it will take to notice diffusion in air rather than having a proximal distance of the starting point. A. Methods and Materials:
Table 1: Results for Osmosis
Cell Mass (g)
Table 1 displays diffusion of water through a selectively preamble membrane.
Table 2: Biochemical Transport
Table 2 represents the results of biochemical testing “+” indicates it was positive “-“indicates that the test was negative. Table 3: Diffusion in a Gel
Potassium Permanganate (KMnO4)
Diffusion Rate (mm/hr.)
Potassium Permanganate (KMnO4)
Diffusion Rate (mm/hr.)
Table 3 demonstrates diffusion rate in a gel as the solutions Methylene blue and Potassium Permanganate diffuse throughout a gel for an hour in different temperatures. Table 4: Diffusion in a Liquid
13 minutes 37 seconds
Table 4 illustrates diffusion rate in a liquid of 1 ml dye solution to diffuse completely in 100 ml deionized water in two different temperatures one being cold and the other room temperature.
Table 5: Diffusion in Air
Table 5 shows the rate of diffusion of air as a scent travels across the room and is first identified. Graph 1: Filtration
Number of Drops
Graph 1 demonstrates filtration rate as copper crystals try to pass through a filter.
C. Discussion/ Conclusion
In the first experiment which was the osmosis and biochemical testing the hypothesize was correct. The tonicity and diffusion rate was affected by the state of matter. In osmosis the cell increased in sized because the tonicity was hypotonic it changed the mass of the cell after an hour. For biochemical testing the environment affected the outcome of weather the transportation of diffusion had taken place. Glucose was tested with benedict to try to find the presence of sugar. The environment had a negative outcome making the water turn dark brown but in the cell it had a positive outcome showing that the presence of sugar was there therefore having the color turn from clear to dark orange. Albumine was tested with biuret to find protein; both the environment and the cell had a positive outcome causing it to go from clear to a light purple color. NaCI was an AgCI precipitate test to discover CI¯ ions. The environment and cell had the same results indicating there was presence of CI¯ ions due to the color change of clear to white. The last test was starch and it was tested with lugols iodide. In this experiment the environment had a negative outcome but the cell had a positive outcome showing it had the presence of starch due to the color change of a bluish color. The second experiment which was diffusion in gel the hypothesis was incorrect. It was hypothesized that the room temperature plate would have a higher diffusion rate but it actually was not the only one. Diffusion occurred at a higher speed for both room and cold temperature but only with potassium permanganate, methylene blue had little to no diffusion throughout the hour calculations; it had no errors. For the third experiment, diffusion in a liquid, the hypothesis was correct it was hypothesized that the rate of diffusion would be greater at room temperature and the results did follow through with that. At room temperature the rate was impressively
greater than at cold temperature, within the first few seconds the blue dye diffuse completely in the deionized water however it took up to thirteen minute to diffuse completely throughout the deionized water. For the fourth experiment which was the diffusion in air the hypothesis was correct, the farther you are from where the Lysol is sprayed the longer it takes the person to detect the smell unlike someone who is closer to where it was initially sprayed. At last for the fifth experiment the hypothesis was correct. The size of material trying to pass through a filter does affect the outcome as to what is let passed through and what is not. The charcoal was not able to pass through the filter because the size of it was too big to be able to. Overall diffusion rate is affected by every single thing from size of particles to the temperature of what the experiment is being tested in. The data and experiments can be related to many everyday life situations. For example the human body filters out waste and unnecessary things that can harm the body; it also cleans out blood to bring in clean blood. A way to improve this experiment is by allowing more time to be able to test each hypothesis at slower pace to get better results and more accurate data.
Allen C., Harper V. 2009. Laboratory manual for anatomy and physiology. New Jersey: Jon Wiley & Sons. p 31-50. Cell Membrane Transport. Fall 2013 Protocol – Department of Biology, Zoology Laboratories. 2013. Available from: Texas Woman’s University, Denton, Texas. Grabowski SR, Tortora GJ. 2003. Principles of anatomy and physiology. Von Hoffman Press, Inc.10th ed. New Jersey: John Wiley & Sons, Inc. p 60-102.