Agar Jelly Lab Report

The identification of unknown organisms carries important ramifications that can be applied to many real world scenarios. In keeping with quality assurance beverages, food, cosmetics, and other products are frequently inspected for contaminants resulting from a presence of pathogenic bacteria. In medicine, a physician’s diagnosis and consequent treatment is largely determined from samples collected from infection sites that have been analyzed using microbial tests.

The purpose of this experiment was to test diffusion of molecules across the cell membrane to see which factor of time, concentration, and mass took effect of increase or decrease of diffusion over time.

The claim to this Agar Pieces lab is that the cells that have a larger surface area to volume ratio are more efficient at diffusing essential nutrients. Another solution, is the rate of diffusion is related to cell size. Nutrients diffuse at a faster rate through small cells than they do through large cells. In this lab of Agar gel, the purpose of this experiment is to find the surface area and volume of the cell that may affect the ability of the molecule to be able to diffuse the cellular space.

The diffusion occurred because the alkali in the agar cubes reacts to the vinegar causing the the cubes to turn yellow from green. The lab displayed how cells would diffuse materials in their membrane. The agar with largest ratio sized at 0.5 centimeters changed colors at 1.33 minutes while the agar with the smallest ratio with size of 2.0 centimeters changed colors at 38.2 minutes. This data supports my hypothesis because it shows that agar smallest ratio took the longest time for it to change colors. From my observations of the agar in the vinegar, I can conclude that cells with a smaller surface area to volume ratio would be less efficient at diffusing materials than a cell with a larger one.

When isolating the types of bacterium that is gram-positive, motile, halophilic, mannitol fermenters that grow in the presence and absence of oxygen you would use the mannitol salt agar (MSA), mannitol fermentation, and semisolid stab tests. To isolate a halophilic bacterium, mannitol salt agar (MSA) can be used as a test. For a mannitol salt agar (MSA) test, you would need a plate where the agar is mannitol salt and 7.5% NaCl. The 7.5% NaCl mix with mannitol shows the selective and differential part of the test because some bacterium is not able to tolerate the high level, but can be mannitol fermenters.

In this lab, two procedures were done in order to show how different types of solutions diffuse into each other. The use of corn starch and potassium iodide in the first procedure were to indicate how simple diffusion works. Because of the way that potassium iodide interacts with cornstarch, a dark blue color in the solution would indicate that diffusion had taken place. The second procedure used potato samples and a glucose solution. After a while, the potato samples were measured for a difference.

The first part of this three part lab was an investigation that examined the relationship between rate of diffusion and the surface area to volume ratio. To simulate this, we used an agar cube with NaOH and phenolphthalein mixed in, and dropped it in an HCl solution. As the HCL diffused in and reacted with the phenolphthalein, we were visually able to see diffusion at work.

In this experiment, I wanted to find out if vinegar, water, dyed water, and/or salt water can go through the membrane of a chicken egg. Before starting my experiment, I read that the cell membrane controls what goes in and out of the cell and found I also learned that small enough molecules can go in and out of the cell through the process of diffusion. In addition I learned that the two different types of diffusion, passive and active transport, determine whether the process of diffusion is going to use energy or not.

YEAR 11 SACE BIOLOGY    THE EFFECT OF CONCENTRATION GRADIENT ON THE RATE OF OSMOSIS    Introduction:    Water is the most abundant substance in any cell. All the chemical processes of a cell involve water in some way.     Osmosis is diffusion of water between a cell.   The following factors could affect the rate of osmosis: the solute concentration inside and out of the cell.

Cells, the smallest functional unit in an organism, contain several organelles and carry out functions of life. The cell membrane is an organelle that holds the cell’s contents, and it allows for certain molecules to pass through, which is why it is referred to as selectively permeable. Diffusion and osmosis are two main transport methods for moving molecules across a cell’s membrane. Diffusion takes place when molecules move from an area of high concentration to low concentration. The same process occurs with water molecules, only it is called osmosis. By conducting an experiment with four different activities, the goal is to

Objective The objective of this lab was to be able to view the process of diffusion and osmosis through a membrane. This will help to reinforce my knowledge of how diffusion and osmosis work by seeing it in action. The method and materials by which I accomplished this are explained below. Method & Material

The season for fresh fruit is quickly approaching as weather conditions continue to improve. Fresh fruit is a beautiful and exciting way to incorporate important nutrients into the daily diet. Unfortunately, fruit does not stay fresh forever, so it useful to know how to properly preserve fruits to keep them safe and nutritious.

Adriana Alvarez 2/19/16 Diffusion and Osmosis Lab Report Diffusion and Osmosis Lab Report Introduction In this experiment, potatoes and glucose were used in order to simulate the process of cells maintaining a normal state in aqueous solutions. The cell will move certain solutes across the membrane of the cell by a process called diffusion. Diffusion is a process in which molecules from a high concentration to a low concentration in order to reach a state of equilibrium (Lab Manuel 94).

The interpretation of the results led us to believe the organism was Staphylococcus aureus. Although some of the results did have complications: The Mannitol Salt Agar appeared to show no signs of growth, but we assumed the color transition of the medium signified minuscule growth. Moreover, the gram stain had complications as well; at first, it appeared to be gram-negative cocci, then after another gram stain we determined that the Unknown was gram-positive cocci. After concluding the gram reaction of the bacterium, a series of tests were performed to differentiate between different genera of gram-positive cocci. The catalase test was a definite positive, which implied the bacterium belonged to Group VI in the lab manual.

It showed that if the pore of a membrane is not large enough, diffusion will not occur. However, if the pore was large enough and diffusion subsequently occurred, the rate of diffusion was the same even if the molecular weight cut off (pore size) was bigger. The following solutes and their simple diffusion data will be explained in order from smallest to largest, smallest being one that was able to fit through smaller a pore size.