The structure of the cell membrane consists of the phospholipid bilayer organized by the arrangement of hydrophilic heads and hydrophobic tails. Diffusion is the process by which molecules of a substance move from areas of higher concentration of that substance to areas of lower concentration. Diffusion works the same way, as osmosis only it is the passive movement of particles in an rear. Cell Membranes Lab Report Student Name: I. There are two methods of transport which can occur through the plasma membrane. The purpose of this experiment is to investigate whether osmosis occurs across the membrane of potato cells.
Introduction All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The tubing may not have been submerged in the beaker for long enough to reach equilibrium. Fill a 250 mL beaker or. In the final trial fill another dialysis bag with 5% salt solution and place it in the sugar water beaker and measure then record the conductivity for two minutes. Put the following in order from. The hypothesis stated that there was a direct relationship between solute concentration and diffusion rate. Conclusion: The word osmosis refers to the diffusion of water across a selectively permeable membrane in order to evenly distribute concentration levels on both sides of the membrane.
Salt is an electrolyte that induces conductivity of electricity in eater. Dialysis Tubing Experiment We tested the permeability of the dialysis tubing to glucose, starch, and iodine. The independent variables here are the water and the karo syrup, while the independent variable is the rate of change in the size of the raisin due to the direction the water will move; either into or out of the raisin itself. You can download this useful Lab report in three formats i. The solution with the most rapid hemolysis time was 0. Results of this lab do support the proposed hypotheses, as hemolysis did occur to the red blood cells introduced to both hypotonic solutions of NaCl, and the rate at which hemolysis took place was much more rapid as the temperature was increased.
In our lab, we modeled diffusion and osmosis with a. Five different Elodea leaves were placed on microscope slides, and added to each one was a different concentration of salt water. The results were as expected in Part B. Materials and Methods: Our lab procedure. After 15 minutes of submersion in the beaker solution, the baggie had turned a dark purple color.
Set up logger pro device to measure electrical conductivity with probe. Diffusion can be the transfer of anything anywhere. Hypotonic is when the solution has a lower solute concentration compared to the water potential. As it began to diffuse its color changed from dark brown to a lighter brown until it becomes a yellow-like orange color. A statistical analysis was done with the null hypothesis being that molecular weight does not affect the rate of diffusion.
If a cell were put in a hypotonic solution, osmosis will cause water to move through the cell membrane into the cell. At the end of the incubation period the time was recorded. It is possible for error in the ability to seal the tubes so that only solute can move into or out of the tube allowed larger amounts of solution to move into or out of the cell. It also contains the method of performing the practical along with the required apparatus. Each leaf had a 1% higher concentration of salt water added than did the previous one. The tubing was also wet when being sealed thus altering the amount of water inside and outside the tubing. The solution that has less solute is hypotonic.
If a cell were placed in a hypertonic solution, it would lose water. The color of the resulting solution was noted. In the laboratory conditions, tube-shaped dialysis bags are commonly used — from a to solid scientific investigations — as artificial membranes for separating differently sized molecules. This means that the solutions have the same concentration of solutes. The beaker solution remained a clear yellow color throughout the experiment; it can hence be inferred that no polysaccharide was present in the beaker solution at the end of the experiment, and in turn, that no starch diffused out of the baggie and into the beaker solution during the 15-minute soaking. At the end of the incubation, we removed the potato samples, and recorded the time.
This is verified because the weight of the dialysis tubing and the beaker both changed. The presence of air or other foreign contaminants in the tubing could have affected diffusion rate. Click analyze, select curve fit and press linear. The rate at which solutes such as salt diffuse across a cell's semi-permeable membrane is affected by a variety of factors. To confirm the tonicity of unknown solutions A, B and C, a potato strip was placed in 3 separate tubes containing each unknown solution. How did the advent of electron microscopy revolutionize cell biology? The diffusion rate actually increased in the presence of sucrose.
Diffusion Lab Report Word Template is a very useful lab report for Biology and Medical students. One such property is diffusivity. These are all examples of diffusion and osmosis. Living cells consist of chemical particles that are highly organized in a complex system, which behavior can be explained by the law of chemistry and physics. To open the other end of the bag, rub the end between your fingers until the edges separate.