Biolab 1208 Lab Report

The corrected cumulative change in weight due to osmosis from different concentrations of sucrose and tap water, are shown in Figure One. This figure shows the weight change in grams for every interval of 10 minutes. Using the corrected cumulative change in weight eliminates bag #1 because its average rate of change will always be zero. Below is a table of the bag weights at 10 minute intervals after being tested for an hour:

I certify that the writing in this assignment is my individual work and is my sole intellectual property. It does not contain the ideas, or writing of other individuals/authors.

I certify that the writing in this assignment is my individual work and is my sole intellectual property. It does not contain the ideas, or writing of other individuals/authors.

Describe the conformation of the phospholipid bilayer of the plasma membrane. What abundant fluid leads to his conformation? Because the phospholipids heads are

The molarity of the solutions in each dialysis bag, and the percent change in mass are both included to best show effect of increasing molarities of sucrose and osmosis. The percent change in mass exhibits the process of osmosis, because osmosis must take place for water molecules to transfer from one side of the semi-permeable (in the surrounding distilled cup) to another (within the dialysis tubing), in order to reach equilibrium.

All cells in the human body are surrounded by a plasma membrane made up of lipids and proteins which form a barrier. The proteins and lipids in the membrane occupy different roles. The lipids create a semipermeable barrier and the proteins are part of a cross membrane transport. To pass through the membrane a substance goes through a transport known as diffusion. Diffusion is movement of molecules from a high area of concentration to an area of low concentration. There are two different forms of diffusion. One example of diffusion is known as simple diffusion, an unassisted movement of dissolved substances through a selectively permeable membrane (Marieb pg. 54). The

out the potato and dry it to ensure excess water is not added to the

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.

The result showed the affects of osmosis, where particles moved to achieve equilibrium. The 0.2 M sucrose had a +8.37% change in mass as a class average and our group and +9.52%. The initial mass for these carrots were 2.1g and became 2.3g when the 2 days had ended. This happened because of the same reason for the 0.0 M sucrose, where the concentration of particles were greater inside the cell compared to the outside of the cell, causing the water molecules moving into the cell through the semi permeable membrane. However, the solution the carrots were dunked into had a 0.2 M sucrose, unlike the first solution. This caused the mass of the carrot to change less because there was already some particles outside of the cell, allowing for equilibrium to become reached a lot faster than 0.0 M sucrose. In 0.4 M sucrose, there was a class average of -2.34% and we had -4.76%. The initial mass was 2.1g with a final mass of 2.0g. This was the first solution to have a negative percentage change in mass from the other six. There was a decrease in mass of the carrot because water had moved from the carrot sticks into the solution around is trying to achieve equilibrium. The water molecules had moved from high concentration into lower concentration, moving our of the carrot cells, causing them to

The Effect of Sodium Chloride, Glucose, and Sucrose on Potato Tissue By Rachel Thurmes ABSTRACT This experiment examined the water potential of white potatoes, and compared them to those previously recorded. The validity of van’t Hoff’s Law was also tested by using different solutes in which to test the potatoes. This was done by measuring potato core weight before and after soaking them in solutions of different dissociations, and determining the percent weight change. Then van’t Hoff’s Law was used to calculate the water potential of the potatoes.

If I was asked to place the potato strips in a solution that would cause them to neither gain or lose mass I would have to place the potato strips back in the 0.2 M sucrose solution because in the experiment the potato strips that were placed in the 0.2 M solution for twenty four hours did not gain or lose weight. The solution was isotonic meaning the extracellular fluid (the solution) had the same osmolarity as the fluid inside the cell.

All cells have membranes that are selectively permeable. Selectively Permeable means that the membrane regulates what goes in and what goes out. For this experiment we learned about osmosis. Osmosis is the movement of water across the membrane, from high concentration to low concentration. We also learned from this experiment about, diffusion. Diffusion is when molecules, like water, move across the membrane from high concentration to low concentration. Our experimental groups were from 0 molarity---0.6 molarity of sucrose. We are using the terms isotonic, hypertonic, and hypotonic in this experiment. Isotonic meaning there is not weight change. Hypertonic meaning that there is weight loss. Hypotonic meaning that there is weight gain. The hypothesis we tested was: if put potato into a isotonic solution, then the mass

If the solution contains only sucrose then the osmotic pressure will increase substantially. This would represent a hypotonic solution because more water molecules are entering the cell meaning the solution contains no invertase. If the osmotic pressure has a slight increase than the solution contains sucrose and invertase due to the rate of the sucrose being broken down, however the cell will overtime begin to shrink. If the osmotic pressure remains close to the same than the solution contains no sucrose, containing only water and invertase. We predicted that because the height of the fluid in the osmometer tubing was increasing only a little bit our blue solution was hypertonic and contained invertase and sucrose. The invertase was able to break down sucrose into glucose and fructose which were small enough to be able to leave the cell membrane. This would reflect a hypertonic solution. We predicted this would cause the cell to shrink in size and the height of the fluid would never increase.

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Introduction: The cell membrane of a cell acts as a protective barrier, while keeping together enzymes and DNA used for metabolic processes. The cell membrane exhibits selective permeability, meaning that it hold back disposable waste products products from the cell and only lets important molecules such as water, and oxygen into the cell. The membrane contains pores that depending on their size will let some molecules to pass. The amount and the type of molecules that pass can affect the concentration of water. By definition, osmosis, is the diffusion of water molecules across a selectively permeable membrane from the region of lower concentration to that of high solute concentration until the solute