Module 3 Diffusion Osmosis Tonicity

A solution consists of a solute and a solvent.

What does a solution consist of?

The solvent in a saltwater solution is water.

What is the solvent in a saltwater solution?

Osmosis is the net movement of a solvent from an area of low solute concentration to high solute concentration across a semipermeable membrane.

Define osmosis.

Tonicity refers to the measure of osmotic pressure and how the concentration of solute molecules affects the movement of water across a semipermeable membrane.

What does the term tonicity refer to?

In a hypotonic solution, water moves into the cell, potentially causing it to swell.

What is the effect of hypotonicity on a cell?

In a hypertonic solution, water moves out of the cell, potentially causing it to shrink.

What happens in a hypertonic solution?

Fick’s law relates to the rate of diffusion and how it is affected by different factors.

What is Fick’s law related to?

Increasing the temperature increases the rate of diffusion.

List one factor that increases the rate of diffusion.

The potato should be left in the salt solution for 60 minutes.

How long should the potato be left in the salt solution for measurement?

The saline solutions used are 0.4%, 0.9%, and 10% NaCl.

What is the concentration of a saline solution used in the osmosis experiment?

Higher solute concentration leads to higher osmotic pressure.

What is the relationship between solute concentration and osmotic pressure?

Place the potato in a graduated cylinder filled with water and measure the rise in water level to determine the volume.

What is the procedure to measure potato volume by water displacement?

Eye protection must be worn when working with liquids.

What should be worn for eye protection during lab work?

The main driving force for diffusion is the concentration gradient.

What is the main driving force for diffusion?

Gloves are optional in the lab.

What safety equipment is optional in the lab?

The initial volume is necessary to calculate the percent change in volume after osmosis.

Why is the initial volume of the potato needed for the experiment?

Test tubes should be rinsed and set upside down in the rack to dry.

What should be done with test tubes after the lab?

Diffusion is the net movement of a solute from an area of high concentration to an area of low concentration driven by a concentration gradient.

Define diffusion.

Permeability of the cell membrane and temperature affect the rate of diffusion.

List two factors that affect the rate of diffusion.

Red blood cells have a normal concentration of 0.9% NaCl, which is considered isotonic.

What concentrations are considered isotonic for red blood cells?

Percent change = (Change in volume (ml) / Original volume (ml)) x 100.

What is the mathematical formula for percent change?

Equilibrium refers to the state when the concentration of molecules is equal on both sides of the membrane.

What is meant by 'equilibrium' in terms of diffusion?

Using both hands ensures stability and prevents spills or accidents.

What is the importance of using both hands to carry test tube racks?

Food coloring should be dumped down the sink and the test tubes rinsed.

How should food coloring be disposed of after the experiment?

A stopwatch or phone is used to time diffusion experiments.

What apparatus is used to time diffusion experiments?

Temperature affects the speed of molecules, thus affecting the rate of diffusion.

What are the effects of temperature on diffusion according to the lab notes?

The types of solutions are deionized water, 0.4% NaCl, 0.9% NaCl, and 10% NaCl.

List the types of solutions used in Part Two: Osmosis.

A semipermeable membrane is a barrier that allows certain substances to pass while blocking others.

What is a semipermeable membrane?

Foot enclosing shoes are required as a safety precaution.

What item must be worn on feet as a safety precaution?