Osmosis and Diffusion Lab

A model cell has a 20% solute concentration and is in a 95% water solution.Assume the membrane is impermeable to solute but is permeable to water. Will the cell shrink, swell, or not change in size? A. Shrink B. Swell C. Not change D. Impossible to determine

B. Swell Since the solution in the beaker is 95% water, and the solution in the cell is 80% water, water will flow into the cell and the cell will swell.

What color is visible if iodine is in the presence of starch? A. Violet B. Orange-gold C. Blue-black D. Red

Blue Black

How is the plasmolysis of a plant cell in a hypertonic solution different from what would happen to an animal cell in the same solution?

Both plant and animal cells would shrink in hypertonic solutions, but while the whole animal cell would shrink, plant cells would shrink only within the boundary of the cell wall.

If the cell membrane of a model cell is impermeable to solute, but is fully permeable to water, which process causes that cell use to shrink, swell, or stay the same in size? A. Diffusion B. Facilitated diffusion C. Osmosis D. Active transport

C. Osmosis Water is the solvent in this example, and osmosis is the movement of a solvent from high to low concentration.

A model cell has a 20% solute concentration and is in a 95% water solution.Is the cell hypertonic, hypotonic, or isotonic to the solution it is in? A. Isotonic B. Hypertonic C. Hypotonic D. Impossible to know

Hypertonic

If a membrane allows some molecules to pass, it is called semi or differentially _________

Permeable

Which variables affect the rate of diffusion? Solubility of Molecules Size of molecules concentration of molecules Polarity of molecules

ALL OF THE ABOVE The speed at which diffusion occurs is influenced by the size, polarity, solubility, and especially by the concentration gradient of molecules.

True or False Brownian movement moves molecules from low to high concentration.

False Brownian Movement is random

True or False If the water potential in an environment is higher, water will flow into that environment.

False Water moves from high to low potential

What is the difference between osmosis and diffusion? A. There is no difference between osmosis and diffusion. B. Osmosis moves materials from low to high concentration, diffusion does the opposite. C. Osmosis moves materials from high to low concentration, diffusion does the opposite. D. Osmosis involves the movement of water; diffusion involves the movement of a solute.

D. Osmosis involves the movement of water; diffusion involves the movement of a solute. Diffusion is the movement of material from high concentration to low concentration. Osmosis is a specific type of diffusion. Osmosis specifically refers to the flow of a solvent (usually water) from high to low concentration.

As solute concentration increases, water potential _________ A. Increases B. Decreases C. Stays the same D. Change unpredictably

Decreases If we increase the amount of solute, the proportion of water would decrease. Solute concentration and water potential are inversely proportional. As solute increases, water potential decreases.

The material used in this lab to simulate the permeability of a cell membrane is _________

Dialysis Dialysis tubing is differentially permeable

If you were given an IV in the hospital that was hypertonic to your blood, would your red blood cells shrink, swell, or not change? A. Shrink B. Swell C. Not change D. It is impossible to determine.

Shrink In a hypertonic environment, there is more solute and less water. Water will move from a higher concentration inside of the cell to a lower concentration outside of the cell, causing the cell to shrink.

Hypotonic

The concentration of the solute ( Cell ) is less than the solution is in ( Water ) Causes the cell to Swell

Imagine a bunch of cut flowers in a vase of water. For water to travel up the stems to the leaves, where is the water potential higher, in the stem or in the leaves? A.Stem B. Leaves C. water potential would be equal in leaves and stem.

Stem Water flows from high water potential to low water potential.

Substance #1: 212 mg Substance #2: 1918 mg Substance #3: 50 mg Substance #4: 4 mg If the substances are allowed to diffuse for one hour, what can you predict about the rate of diffusion?

Substance #4 will diffuse farthest because the molecular weight is least.

Hypertonic

The Concentration of the Solute ( Cell ) is greater than the solution is in (Water) Causes the cell to shrink

In the lab, imagine that you are given a section of the aquatic plant, Elodea, to observe. As part of your observation, you prepare a wet mount of Elodea and add a 20% NaCl solution to your slide. What should you expect to see when you observe this slide through the microscope?

The cell will shrink, but the cell wall will be unchanged.

Isotonic

The concentration of both the Solute and the Solution are the same The cell stays the same. NO OSMOSIS

How will the distribution of molecules occur when diffusion is complete in a solution?

The molecules will be distributed evenly in a solution. Diffusion is the movement of material from high to low concentration. This will occur until a uniform distribution of the material is present.

True or False Phenolphthalein turns red in a basic solution.

True Phenolphthalein is used as a pH indicator because it turns red in basic conditions.

True or False A nonpolar molecule will move across a semi-permeable membrane more rapidly than a polar molecule.

True The membrane interior is nonpolar, so nonpolar molecules move across readily.