It is important for an IV solution to have salts in it so the water and solute can be equal to create an isotonic environment. If there wasn’t, there would either be a hypotonic causing the cell to burst, or there would be hypertonic causing the cell to shrink. We created models of living cells by using dialysis tubing. The dialysis tube represented the cell membrane to act as selectively permeable to water and some solutes. We observed different solutes (NaCl, Ovalbumin, Glucose, Sucrose, and Water) in the dialysis tubing.
Osmolarity involves the movement of water across a cell membrane which is osmosis, this movement of water can be hypertonic; a higher concentration of a solute inside the cell which means the cell loses mass, hypotonic; a lower solute concentration inside the cell than outside which means the cell gains mass, or isotonic; a solute concentration the same as the outside of the cell which means there is no net movement of water. In a hypertonic solution in a cell water will leave the cell in order to balance the solute concentration making the cell shrink, in a hypotonic solution however water will enter the cell to balance the concentration. In an isotonic solution water will not move since both sides are equal in concentration. b. Purpose-The purpose of this lab was to determine the osmolarity of plant cells by using potato cores as the cells and sugar as the solute. c. Hypothesis-My hypothesis was that if the amount of solute increases then the then potato core’s weight decreases.
Both flask’s pH went up 4. Which substance, water or the buffer does a better job of maintaining pH when small amounts of strong base are added? Water does a better job at maintaining pH under these circumstances, but only slightly 5. Write equations for the reactions taking place in each of the flasks. For an equilibrium arrow ( ) is an equals sign (=) (Unless you know how to do equilibrium arrows).
If the concentration of water in a cell is lower than the concentration of water in the solute the solution is said to be hypotonic and the cells swell because they will take up water. It is possible for animal cells to swell to the point of bursting because they do not have cell walls to limit the amount of water that enters. Plant cells hold the excess water in their large vacuoles and have cell walls so they remain rigid and further uptake of water will not happen. When the concentration of water in a cell is higher than the concentration of water in the solute the solution is said to be hypertonic and the cells will shrink because the water will diffuse from the cell into the solution. A plant whose cells are in a hypertonic solution will appear droopy because there is a loss of turgor pressure in each cell.
IB Biology Cytology Laboratory 12/12/12 Osmosis in Red Onion Cells WRITE-UP Background Information: Osmosis is the diffusion of water from an area of low concentration to an area of high concentration across a semi-permeable membrane. The purpose of this lab is to compare the four different types of solutions effect on the size of the vacuole. Hypothesis # 1: If distilled water is added to the membrane of the red onion cell then that vacuole will grow that most or stay the same because is that same concentration inside and outside the cell which mean no net movement and that cell will stay the same. Hypothesis # 2: If 1 % of saline solution is added to the membrane of the red onion cell then, that vacuole will start to slowly decrease size because water will start to move towards that higher solute. But it won’t be as strong as if that solute were higher.
The cell membrane is selectively permeable so that a cell would lose water when placed in a higher solute concentrated environment and gain water when placed in a lower solute concentrated environment because of osmosis. Osmosis does not occur when there is no concentration gradient, meaning that the solute concentration of inside and outside of the cell is the same. The solution is called isotonic when the concentration of the solution is the same as the concentration inside the cell. Hypothesis * As the sucrose concentration of the solution decreases, the percentage change in mass solanum turberosum discs will increase because the greater concentration gradient results in more rapid and intense osmosis. In the solution of isotonic sucrose concentration, solanum turberosum discs will not gain or lose any mass since osmosis would not occur.
This is a diffusion where the movement of water from an area of high water concentration is moved to an area of low concentration. This experiment takes place to measure the diffusion of small molecules throughout dialysis tubing. This tubing acts as a selectively permeable membrane, allowing the larger molecules to pass through, but slowly. When the two solutions on either sides of the membrane are equal and no net movement is detected, the solutions are isotonic. This means that the solutions have the same concentration of solutes.
1 mark AND Enzymes function best at their optimum pH, which in this case has been found to be (whatever their results indicate). When enzymes are acting at their optimum level the maximum amount of oxygen gas will be produced. 1 mark AND Enzymes begin to be denatured when the pH of the surrounding environment moves away from the optimum pH. The rate and extent of denaturation increases as the pH value moves away from the optimum pH. 1 mark AND Extreme pH denatures the enzyme, altering the shape of the active site and preventing the enzyme and substrate forming a complex, thereby decreasing the rate of the reactions.
Smaller solutes and fluid pass through the membrane, but the membrane blocks the passage of larger substances (for example, red blood cells, large proteins). This replicates the filtering process that takes place in the kidneys, when the blood enters the kidneys and the larger substances are separated from the smaller ones in the glomerulus. a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. In this lab, one will observe the properties of diffusion and osmosis and model the data one receives on a standard curve. With knowledge of water potentials, one can chart the gains and losses of water to find the molarity of a specific solution.
1.2- Important factors affecting osmosis and diffusion would be how concentrated the solution or solute is, the temperature that the environment or the solution is. What your using and also how large the particle is. 1.3- Aim: The aim of the experiment is to document a rhubarb cell under a microscope, using different concentrations of salt-water solution to determine how much the cell decreases in size, volume and shape and to record the difference in cell reduction. (2) 1.4- Hypothesis: This experiment we expect that the rhubarb cells will drastically shrink with the higher concentrations of salt-water solutions. 1.5- Before starting this experiment we didn’t know how drastically the rhubarb cell would shrink, or if this experiment would actually be a success.