When the concentration of the surfactant solution exceeds the critical micelle concentration (CMC) whereby the surface of the solution is full of surfactant molecules, the remaining surfactant molecules self-assemble into groups called micelle. The hydrophilic head of the surfactant molecules would be at the outer side of the micelle in contact with water, leaving the hydrophobic tail of the molecules in the interior of the micelle as shown in the diagram below. In order to increase surface area of a solution, the work required is proportional to the amount of molecules at the surface of the liquid, following the equation below where dA is the difference in surface area and γ is the surface tension. δW = γ . dA When a drop of liquid is released on to a solid surface, it rests and forms a lens-shape which is controlled by three forces: the surface tension at the solid/vapor interface γSV, surface tension at the solid/liquid interface γSL, and the surface tension at the liquid/vapor interface γLV.
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.
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.
Dialysis Lab Background: Dialysis works on the principles of the diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane. Diffusion is a property of substances in water; substances in water tend to move from an area of high concentration to an area of low concentration. Blood flows by one side of a semi-permeable membrane, and a dialysate, or special dialysis fluid, flows by the opposite side. A semipermeable membrane is a thin layer of material that contains holes of various sizes, or pores. 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 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.
A plant whose cells are in a hypertonic solution will appear droopy because there is a loss of turgor pressure in each cell. When the concentration of water is the same in the cell and the solute the cell is said to be isotonic and is at equilibrium. There is no net movement of water across the membrane. (Biology Department, 2010). Surface area to volume ratio has a direct effect on the amount of water (as well as nutrients and waste) that can diffuse through the plasma membrane.
The nephron itself will then restore the vital nutrients and water back into the blood, while retaining the waste products the needs to eliminate, through the proximal and distal tubules. When there are no diuretics in the blood, when tubular reabsorption occurs through the proximal tubule, selective reabsorption of nutrients, such a sodium ions, from the filtrate go back into the blood. So, when sodium ions are reabsorbed by the blood, negative ions such as chloride ions follow due to the charge attraction. The highly concentrated solutes create an osmotic force, so water is also reabsorbed and is also reabsorbed. Then the filtrate goes through the descending loop of Henle, which is permeable to water (water retained back), and then through the ascending loop of Henle, which is permeable to salt (salt is retained back).
Use your answers to Questions 1 and 2 to explain how a water-insoluble organic acid might be freed of non-acidic impurities. Water-insoluble organic acid can be freed of non-acidic impurities by adding strong base into it during fractional distillation. The water-insoluble organic acid will react with the strong to produce an ionic salt which is soluble in water. On the other hand, water-insoluble organic acid which are slightly soluble in water can be extracted by aqueous base from solution in an organic solvent. The fact that organic acid are weak acids and only partially dissociates in
If a cell is in contact with a solution of lower water concentration than its own contents, then water leaves the cell by osmosis, through the cell membrane. Water is lost first from the cytoplasm, then the vacuole through the tonoplast. The living contents of the cell contracts and eventually pulls away from the cell wall and shrinks, this is known as Plasmolysis. If you put a plant cell in water, water enters by osmosis, then swells up. However, the cell will not burst.
Title: Osmosis in quail eggs Introduction: Osmosis is the net movement of solvent molecules through a partially permeable membrane into a region of higher solute concentration, in order to equalize the solute concentrations on the two sides. Net movement of solvent is from the less concentrated (hypotonic) to the more concentrated (hypertonic) solution, which tends to reduce the difference in concentrations. This effect can be countered by increasing the pressure of the hypertonic solution, with respect to the hypotonic. The osmotic pressure is defined to be the pressure required to maintain equilibrium, with no net movement of solvent. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity.