Formulation, Testing of Hypothesis, and Experimental Design

2. Does the rate of diffusion correspond with the molecular weight of the dye? The the density of the medium and the molecular weight of the dye will determine the rate of diffusion.

Cells and molecules in the environment are constantly moving and changing, for cells to function properly there is a need for equilibrium to be met. The size of the cell and the solution outside of the cell affects the rate of diffusion and osmosis in the cell. Cells are constantly trying to reach an equilibrium with the molecules and substances around it, which is why there are such terms as: hypertonic, hypotonic and isotonic. The procedures allowed testing of whether or not surface area or volume increased diffusion and how different substance control diffusion. Cells are constantly moving to reach equilibrium through diffusion and osmosis.

2. Explain your observations in detail in terms of concentration gradient, diffusion, osmosis, osmotic pressure, passive transport, and active transport.

B. The nature of plasma membrane. If the membrane is composed of lipid portion., only lipid soluble molecules can pass through while water molecules cannot.

Two variables that affect the rate of diffusion are the MWCO membrane and the solute concentration. Increasing the membrane size and solute concentration will also increase the average diffusion rate. Decreasing the membrane size and solute concentration will reduce diffusion rates and can even prevent all diffusion.

Hypothesis: I expect to find that when the surface area to volume of a cell reaches a certain level, diffusion alone won't be able to supply

7. Explain how incubation plant tissues in a series of dilutions of sucrose can give an

1. Understand the importance of diffusion to cellular metabolism and the how it constraints the evolution of cell/body size and shape

A major determinant of diffusion in a biological system is membrane permeability. Small, uncharged molecules pass through cellular membranes easily, while most and/or charged molecules cannot pass through the membrane. The movement of water across a selectively permeable membrane, like the plasma membrane

The difference is that along with large molecules, living cells prevent molecules with positive charges and solubility. This is not representing in dialysis tubing, and is only found in living cells because the tubing is only based on molecular size (98). When referring the rate of diffusion, the concentration gradient influences the diffusion rate, based on the factors of temperature. The ability for molecules diffuse from high to low concentrations primarily depends on the concentration gradient between the two areas.(96-99). My hypothesis for the study is that in the hypotonic, hypertonic, and isotonic solutions, the direction and rate of osmosis will determine based on the concentration inside the dialysis tubing. My prediction is 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 assimilate diffusion through a permeable membrane potassium permanganate and methylene blue were used in experiment. The objective was to compare the rates at which the liquid compound of different molecular weight diffused through agar. This was achieved by obtaining agar in a petri dish with two wells to hold the liquid compounds. The rate was measured by time and diameter distance diffused. This process was observed for 60 minutes at 15 minute intervals.

In conclusion, the potato cube with the highest surface area to volume ratio (the 1x1x1 cube) had the fastest rate of diffusion as it had the largest percentage increase in mass. While all the other cubes of potato had larger increases in mass at face value compared to the smallest cube, the smallest cube had the largest overall gain in percentage. The results support my hypothesis that the smallest cube will have a higher rate of osmosis because it has a proportionally larger amount of surface area compared to its volume.

Diffusion is the transfer of molecules from an area that has a higher concentration to an area that has a lower concentration. Osmosis is the diffusion of water. The purpose of this experiment was to study the process of osmosis. In order to test osmosis, eggs that had been soaking in vinegar were taken and placed in four beakers of solution with different levels of glucose. Using this experiment we were able to determine the rate of osmosis of different solutions, with various amounts of glucose, through eggs. In the results of this lab it was found that the eggs were either hypertonic or hypotonic and that the

a. The study was designed as an experimental research by using independent and dependent variables.

Diffusion is the spontaneous movement of particles from where they are more concentrated to where they are less concentrated. For this experiment, a 14 cm glass was filled with cold tap water. A drop of red food coloring was dropped in the cup. A stopwatch was used to measure the time it took for the food coloring to get to the bottom of the cup. The average diffusion rate was .78 cm a second. If a different color was used, I do not think it would have made a difference in the results. The mood of the person experimenting could possibly alter the results. For example, if a person is under stress, they may accidentally squeeze too much altering the rate of diffusion. If the water was warmer, this may have sped the