Osmosis lab Essay

Custom Student Mr. Teacher ENG 1001-04 22 August 2016

Osmosis lab

The Measurement of the Rate of Osmosis by using “Deshelled” Chicken Eggs (Effect of Solute Concentration upon Rate/Degree of Osmosis in Chicken Eggs)

Introduction

Every cell needs a mechanism that it uses in the maintenance of a constant internal environment. This is important in the control of the ever changing external environment to the cell. The transfer of materials to and from the cell thus needs a very stable mechanism to achieve this status. Cells are therefore bound a membrane that acts the selective controller of the movement of different substances to and from the cell. This is especially when dealing with the solutes both to and from the cell. Some solutes must be allowed to move into and out of the cell depending on the need and urgency of the very solutes.

This membrane is considered to selectively permeable to different solutes and thus will only allow the passage of specific solutes to and from the cell. This implies that the membrane to most cells is selectively permeable or has a differential permeability to different solutes. Both the internal and the external environment to the cell are composed an aqueous solution that is made of dissolved organic and inorganic substances.

The gradual or spontaneous movement of these substances in and out the cell are guided by a mechanism called diffusion. This is a movement by molecules to a region of lower concentration from that of higher concentration. A good number of studies have been used in the biology field that are related to the use and importance of such passive movements in the cells and the entire organisms. There exist a number of passive movements that are vital to the functioning of several organisms. These include movements like diffusion, osmosis and others. However, the paper will be pegged onto the factors related to osmosis. The experiment will try to underscore the importance of osmosis using the shelled eggs cells. This will also encompass the effects of several salt concentrations to the egg cells.

Research Questions

The paper tires to answer a number of questions related to osmosis. First, it seeks to understand and illustrate the importance of osmosis to the cellular life of an organism. It will also seek to underscore the vitality of the osmosis process to the mode of transport in the egg cells. It will go ahead to explain the relevance of different solutions to the eggs cells. It then explains the role and importance of osmosis to the tissues and cells in the body.

When dealing with osmosis, we use several terms. These are the hypertonic, hypotonic and the isotonic. These are used in relation to the relative concentrations of such solutions to the cell sap being investigated. Curtis defined these terms as illustrated below. Hypotonic is the solution that contains a low concentration of the solutes particles. Water will always move away from the hypotonic solution. In a typical cell, the hypotonic solution becomes the reference point or the control in the experiment just like in this experiment. This implies that the solution has lesser particles in comparison to that of intracellular space.

The hypertonic solution on the other hand, refers to the solution that contains higher concentration of particles. It refers to the solution that has a higher concentration s compared to that of the intracellular space. Water will always move across the semi permeable membrane into the hypertonic solution in the cellular setting. This simply implies that the hypertonic solution has more concentration of the particles than the intracellular space. Finally, the isotonic solution contains the solutes with the same concentration as those of the other solution in comparison. When these two isotonic solutions are separated by a semi permeable membrane, then there will be a net flow of water across the membranes.

Research Hypothesis

It is right to pre-empt that the eggs cells will react to the different solutions used in the experiment. This will be in the three different ways discussed above as hypotonic, hypertonic or isotonic solutions. The solutions will have a relative concentration in comparison to that of the eggs cells sap.

Materials and Methods

Part I: Effect of the Solute Concentration

Each group of students were given 2 chicken eggs from which the shell had been dissolved away. The remaining membrane that was the shell membrane was considered to be differentially permeable. Each egg was assumed to have approximately the same concentration of solute in the membrane. Based on the rate of osmosis, the experiment attempted to determine what the concentration must have been. Each egg was then weighed separately to the nearest 0.1g and results recorded the weights in a Table at time “0.”Each egg was again placed into separate beakers containing solutions of either distilled water (0%), 10% sucrose, 20% sucrose, 30% sucrose, 40% sucrose and an unknown sucrose solution.

At 15 minute intervals that is after 15, 30, 45, 60, and 75 minutes, the eggs were removed from the beakers. They were then carefully wiped off all excess water; and again each egg weighed separately. Record the weights or masses were then recorded and weight changes placed in the Tables. Plot the changes in weight of each of the eggs were then plotted against time in a graph as shown in the results section. Several questions were then answered based on the results obtained. Which solutions would you say were hypotonic to that of the eggs? Which of them were hypertonic? Isotonic if there were any?

What would you expect to happen if an egg was put into a sixth beaker containing a 50% sucrose solution? Results

Graph 1: Weight of Eggs versus Time

Graph 2: Change in weight of eggs versus Time

Graph 3: Last Minute versus Sucrose Concentration

The osmotic pressure in the cells and tissues usually take the same function and illustration as those in vivo tests. This process is usually attained through the use of some controls in the experiment with known concentrations. The relativity of the solutions could then be detected using a very simple comparison exercise just like illustrated above. Both the vitro and the vivo tests take the same parameters in such experiments. This implies that the same results will be viewed if such experiments are carried out on mammalian cells like the shelled eggs cells used in this experiment.

The fluid under test could be hypertonic, hypotonic or isotonic to the cell sap of the eggs cells used in this experiment in one way or the other. Just as illustrated in the introductory part of this paper, the hypotonic is the solution that contains a low concentration of the solutes particles. Water will always move away from the hypotonic solution. In a typical cell, the hypotonic solution becomes the reference point or the control in the experiment just like in this experiment. This implies that the solution has lesser particles in comparison to that of intracellular space.

The hypertonic solution on the other hand, refers to the solution that contains higher concentration of particles. It refers to the solution that has a higher concentration s compared to that of the intracellular space. Water will always move across the semi permeable membrane into the hypertonic solution in the cellular setting. This simply implies that the hypertonic solution has more concentration of the particles than the intracellular space. Finally, the isotonic solution contains the solutes with the same concentration as those of the other solution in comparison. When these two isotonic solutions are separated by a semi permeable membrane, then there will be a net flow of water across the membranes.

Discussion

From the results in the section above, it is important to underscore the vitality of the biological membranes in the system of most organisms. It is clear that all biological membranes are indeed semi permeable to specific solutes. This implies that they are selectively permeable to water molecules and other important solutes in the functioning of such organisms. However, their great importance comes in when they are impermeable to several other solutes in the body that are neither important to the cells nor the tissues of the body. These solutes that are impermeable to the biological membranes include solutes like the charged molecules that include ions of Na, K, Ca and Cl.

The isotonic solution used in this experiment contained 30 % sucrose and this acted as the control to the experiment. The concentrations below this concentration of the isotonic solution were considered as hypotonic and these incl.ude the 10 and the 20 % sucrose solutions in the experiment. The other concentrations that were above this isotonic value gave the hypertonic solutions and this was the 40 % sucrose solution. Water molecules moved from the hypotonic solution to the inside of the eggs cells to make them swell and become larger and even a god number of these cells were burst due to the excess osmotic pressure built by the effect of the hypotonic solution.

The eggs cells that were placed in the isotonic solution never gave any visible change in their form and structure as the concentrations for the solution and that of the cell sap were similar and equal. Those eggs cells that were placed in the hypertonic solution became flaccid. This was due to the movement of water molecules out of the cell into the hypertonic solution. Indeed, the solution in this case increased in volume as opposed to the hypotonic solution that reduced in volume.

Conclusion

In a nut shell, the experiment proved successful as the objectives of the practical were met to the letter. The hypothesis also proved valid and in line with the objectives. It implies that the different concentrations of sucrose used in the experiment gave varied effects to the cell sap of the eggs cells. The practical clearly demonstrated the effects and process of osmosis to the eggs cells. It also demonstrated the importance of different solutions to the functioning of the cells and tissues in the body of mammals. This was in response to the process of osmosis in the body.

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  • University/College: University of Chicago

  • Type of paper: Thesis/Dissertation Chapter

  • Date: 22 August 2016

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