roy

Since plant species evolved for survival in different environments, their internal solute concentrations should be different from their marine ancestors. Which hypothesis do you think is more likely to be true? PART III: DESIGN YOUR OWN EXPERIMENT Do plants living in a freshwater pond have the same solute concentrations inside their cells as plants living […]

Red blood cells will burst if placed in distilled water (0% salt). Why didn’t the onion cells burst? The number of plasmolyzed and unplasmolyzed onion cells in different concentrations of salt solution. Salt concentration Number of cells plasmolyzed Number of cells counted Percent of cells plasmolyzed 0% 1% 2% 3% 4% 5% 6% 7% 8%

Using the plasmolysis threshold to estimate the concentration of solutes and water inside living cells Under your compound microscope, the cell membrane of a turgid cell is invisible because it is pressed up against the inner surface of the cell wall. But in a plasmolyzed cell, the cell membrane is visible because it has pulled

  PART II: WATER CONTENT OF CELLS Although living tissue is about 75-85% water, the effective concentration of solutes inside cells is not 15- 25%. Most of the non-water components of cells are bound into cell structures and are not in solution, so do not influence osmotic pressure. It is the concentration of solutes (substances

why does the fluid level in the osmometer rise, at least at first? Analysis and Discussion 1. In terms of water molecules and solute concentration gradients, why does the fluid level in the osmometer rise, at least at first? (Hint: Think about the concentration gradient and the net movement of water at the molecular level.)

at what height did the column of fluid in the tube stop rising? Immediately mark the level of the solution in the glass tube by wrapping a second piece of wet string twice around the tube. Move the string to mark the starting level of the fluid in the glass tube. At 5 minute intervals,

Movement of water into a model cell In Exercise 1, as water moves by osmosis into a dialysis bag (our “model cell”), the pressure in the bag increases. You will quantify this pressure change by measuring the height of the water in a glass tube inserted into the bag (See Figure 1). A taller column

The Osmometer Osmotic pressure is the tendency of water to move into a cell. An osmometer is a device designed to measure osmotic pressure by measuring the amount of internal hydrostatic pressure needed to stop the movement of water into a cell. The osmotic pressure experienced by a cell differs under different environmental conditions. Figure

One of the principal ways molecules get in and out of cells is diffusion. Diffusion is defined as the net movement of molecules from areas of higher concentration to areas of lower concentration. For example, if you place a crystal of a purple dye in a glass of water, the purple color spreads out as

Lab 3 – Cell Membranes and Water Balance 8 PLAN AHEAD! This lab requires working with a partner and writing a lab report. Osmosis is the vitally important process by which water moves in and out of cells. Overall, the cells of living organisms are composed of about 75-85% water. The concentration of water is