This tutorial will help you understand how animals adapt to their habitat. For instance, how animals thrive in aquatic habitat and are able to overcome osmosis.
It also sheds light on the reasons animals adapt Read More. Molecules move within the cell or from one cell to another through different strategies. Transport may be in the form of simple diffusion, facilitated diffusion, active transport, osmosis, endocytosis, exocytosis, epithelial transport, or glandular secretion.
Eventually, the concentration of "stuff" on either side of them will even out. A fish that lives in salt water will have somewhat salty water inside itself. Put it in freshwater, and the freshwater will, through osmosis, enter the fish, causing its cells to swell, and the fish will die. What will happen to a freshwater fish in the ocean? The sugar dissolves and the mixture that is now in the cup is made up of a solute the sugar that is dissolved in the solvent the water.
The mixture of a solute in a solvent is called a solution. Just like the first cup, the sugar is the solute, and the water is the solvent.
But now you have two mixtures of different solute concentrations. In comparing two solutions of unequal solute concentration, the solution with the higher solute concentration is hypertonic , and the solution with the lower solute concentration is hypotonic. Solutions of equal solute concentration are isotonic. The first sugar solution is hypotonic to the second solution.
The second sugar solution is hypertonic to the first. You now add the two solutions to a beaker that has been divided by a semipermeable membrane, with pores that are too small for the sugar molecules to pass through, but are big enough for the water molecules to pass through.
The hypertonic solution is one one side of the membrane and the hypotonic solution on the other. The hypertonic solution has a lower water concentration than the hypotonic solution, so a concentration gradient of water now exists across the membrane. Water molecules will move from the side of higher water concentration to the side of lower concentration until both solutions are isotonic.
At this point, equilibrium is reached. Red blood cells behave the same way see figure below. When red blood cells are in a hypertonic higher concentration solution, water flows out of the cell faster than it comes in.
This results in crenation shriveling of the blood cell. On the other extreme, a red blood cell that is hypotonic lower concentration outside the cell will result in more water flowing into the cell than out. This results in swelling of the cell and potential hemolysis bursting of the cell.
In an isotonic solution, the flow of water in and out of the cell is happening at the same rate. Cells in an isotonic solution retain their shape. Cells in a hypotonic solution swell as water enters the cell, and may burst if the concentration gradient is large enough between the inside and outside of the cell.
Cells in a hypertonic solution shrink as water exits the cell, becoming shriveled. Hypotonic Solutions Three terms—hypotonic, isotonic, and hypertonic—are used to relate the osmolarity of a cell to the osmolarity of the extracellular fluid that contains the cells. Isotonic Solutions In an isotonic solution, the extracellular fluid has the same osmolarity as the cell.
Key Points Osmolarity describes the total solute concentration of a solution; solutions with a low solute concentration have a low osmolarity, while those with a high osmolarity have a high solute concentration. The size of the solute particles does not influence osmosis. Equilibrium is reached once sufficient water has moved to equalize the solute concentration on both sides of the membrane, and at that point, net flow of water ceases. Here is a simple example to illustrate these principles: Two containers of equal volume are separated by a membrane that allows free passage of water, but totally restricts passage of solute molecules.
Solution A has 3 molecules of the protein albumin molecular weight 66, and Solution B contains 15 molecules of glucose molecular weight Into which compartment will water flow, or will there be no net movement of water? When thinking about osmosis, we are always comparing solute concentrations between two solutions, and some standard terminology is commonly used to describe these differences:.
Diffusion of water across a membrane generates a pressure called osmotic pressure. If the pressure in the compartment into which water is flowing is raised to the equivalent of the osmotic pressure, movement of water will stop.
0コメント