Diffusion Lab Report

Certain substances are able to diffuse across plasma membranes under the right conditions through selective permeability. The selection of these certain substances allows for cells to maintain homeostasis, as these substances move from higher concentration to lower concentration. The purpose of this experiment is to see whether or not Lugol’s will be able to diffuse across dialysis tubing, which acts as a membrane. Lugol’s turns black when it interacts with starch, which will make the diffusion easy to see. This is all based off of a caterpillar eating a plant. The starch present in the leaves causes the caterpillar to produce amylase, which breaks down starch. In one experiment, the tubing will contain starch and amylase, while the other tubing

6. What results would you expect if the experiment started with glucose and Lugol’s Solution

By examining the filtration results, we can predict that the molecular weight of glucose must be

When glucose carriers in the membrane were set to 500, the glucose transport rate for 2.00 mM of glucose was .0008 mM/min. Equilibrium was reached at 43 minutes. At 700 glucose carriers the rate was .0010 mM , and equilibrium was reached at 33 minutes. When the glucose carriers was set at 900 the rate was .012 mM/min, and equilibrium was reached at 27 minutes. After changing the glucose concentration to 8.0 mM, the glucose transport rate with 500 carrier proteins was .0023 mM/min, and equilibrium was reached at 58 minutes. With the simulation set at 700 carrier proteins the rate was .0031mM/min, and equilibrium was reached at 43 minutes. When the simulation was done with 900 carrier proteins the glucose transport rate was .0038, and equilibrium was reached at 35 minutes.

Table 1 shows the contents of the bags and the content of the concentration it was submersed in. Bags 2-4 each contain a solution of both sucrose and water. These bags were each put into beakers containing hypertonic solution. These bags gained weight over time because the water moved from its high concentration inside the beaker to the low concentration inside the membrane of the artificial cell, the membrane being the bags that consisted of dialysis tubing. The

In this lab we found out that the dialysis bag contained more fluids inside it. This can happen because sucrose is small enough to pass through the selectively permeable membrane. Some errors that might have been encountered during the lab could have been the fact that some of the dialysis bags were not tightly tied with the dental floss, or that the wrong substance was used. Another possible source of error was if the carrot strips had been dehydrated from the beginning of the experiment or were already

Three peaks are observed in Figure 1 (concentration of glucose vs. elution volume) which was expected due to the results in table 4 that show intervals of elution. The intervals of the elution are represented as peaks on the graph. The intervals are due to the glucose molecules that enter the beads of the column causing the glucose molecules to elute slowly. Two peaks are observed in Figure 2 (concentration of starch vs. elution volume), which was not expected. One peak was expected for the

The hypothesis states that if the solution is hypotonic the results will decrease, if the solution is hypertonic the results will increase and if the solution is isotonic the solution will vary and or remain constant. In order to test the predictions of the hypotonic, hypertonic, and isotonic hypothesis for the solution  made during the study,  four samples of sucrose were taken and placed into two different beakers each containing a different concentration. Then dialysis tubing A was placed into beaker 1 with B, C, and D placed into beaker 2 for 45 minutes and weighted at 15 minute intervals. My finding in the study was that each of the four samples changed from their initial weight and for the most part accurately proved the hypothesis.

There were several steps completed to prepare for the experiment. Three dialysis tubes were filled with approximately the same volume of distilled water and then were tied shut. The initial mass (in grams) of the tubes was taken using a triple beam scale. I then filled three 500 mL beakers with 400 mL of water each and dissolved different masses of solute (table sugar) in each beaker in order to make 5%, 10%, and 20% solutions. The beakers were labeled accordingly, and then 20 g, 40 g, and 80 g (respectively) of table sugar was weighed out using a digital scale and placed into the corresponding beakers. The sugar was stirred in using a stirring rod until all of the solute was completely dissolved.

The two big sections that all forms of cellular transportation fall into are passive transport and active transport. Passive transport is the moving of material along a concentration gradient (a high concentration to a low concentration). Passive transport requires no use of energy because there is nothing that you need to use energy to work against. Active transport is the moving of material against a concentration gradient (a low concentration to a high concentration). Active transport requires the use of energy because the movement of the material is going against the flow.

Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through

The cell’s energy is used for moving molecules across the cell membrane. This sometimes involves pumping solutes into and out of the cell. This process requires energy so it is known as active transport. During active transport molecules are moved against their concentration from areas of low concentration to ones of high concentration. Examples of active transport occur in the nerve cells and in the intestines. Proteins, ions, large cells, and complex sugars are all types of particles moved by active transport. Active transport uses adenosine triphosphate (ATP) to move molecules from a low concentration to a high concentration. Some proteins are on the inside of the cell while others are on the outside. When they cross the lipid bilayer they can move molecules and ions in and out of the cell.

Active transport requires energy such as ATP (adenosine Triphosphate) to perform its function of moving molecules across a cell membrane to secrete a substance. The Sodium-Potassium Pump is a common mechanism in the body that uses active transport. This pump requires the use of ATP to pump Sodium of the cell as it is working to pump potassium into and across the cell membrane at the same time. Passive transport does not require energy to move molecules throughout the body. This includes diffusion, osmosis, and filtration. Diffusion is the movement of molecules down a concentration gradient. The molecules move from the side of the membrane with a higher concentration to side with the lower concentration. Osmosis is the movement of water across a membrane. The water also moves down a concentration gradient, from the side that is higher to the side that is of less concentration within a cell. Filtration is the movement of water in and out of a cell by

The importance of this computerized simulation study was to gain an understanding of the processes that account for the movement of substances across the plasma membrane, and to indicate the driving force for each. This may also be applied to the study of transport mechanisms in living membrane-bounded cells. Also, understanding of which way substances will move passively through a deferentially permeable membrane depending on the concentration differences. We used PhysioEx software to examine diffusion. In these experiments we used different sized membranes as well as NaCl, urea, glucose, albumin, powdered charcoal, and KCl. The step by step process was used by the software so that we could see the different kinds of

Diffusion is the movement of particles from one high concentration area to a low concentration area. The particles disperse until the entire substance has an identical concentration. Osmosis is the diffusion of a solvent, such as water. The solvent passes from a dilute solution, through a semipermeable membrane, and to a more concentrated solution. Osmosis does not require energy to occur. A semipermeable membrane acts as a barrier, permitting some molecules to pass through and preventing others. Cell membranes and dialysis tubing are types of semipermeable membranes. Dialysis tubing promotes the removal of molecules from a solution. Carbohydrates, lipids, proteins, and nucleic acids are the four types of biomolecules. The biomolecules all serve important functions in living organisms.