Anatomy & Physiology 34A
Labs 5A - Cell Transport Mechanisms
Lab Objectives
A. Define differential permeability, solute, solvent, solution, diffusion, osmosis, isotonic,
hypertonic, hypotonic, active transport, endocytosis, and exocytosis.
B. Describe the processes that allow movement across the plasma membrane.
C. Determine which way substances will move passively through a plasma membrane (given
information on concentration differences), and which require active transport.
Activity 1: Observing Diffusion of Dye through agar gel (work in groups of 4)
- Follow the directions in the lab manual to determine the relative diffusion rates of
potassium permanganate (KMnO4) and methylene blue in agar gel.
- Answer the questions in the exercise.
Activity 2: Observing Diffusion of Dye Through Water – follow directions in the lab manual
and answer the questions in the exercise.
Activity 3: Observing diffusion (osmosis) through nonliving membranes (dialysis tubing)
- Work in groups of four students, with each student doing one of the experiments in the
activity.
- When the experiments are complete, share your data with your lab partners, and answer the
questions posed.
Activity 4: Observing Osmometer Results (demonstration) – follow directions in the lab
manual and answer the question.
Activity 5: Observing diffusion through living membranes (eggs and blood cells in
solutions)
Experiment 1 - Class Demonstration (substitution) – Compare each of the 3 eggs in different
solutions. Name which container contains an isotonic solution, which egg is in a hypotonic
solution, and which is in a hypertonic solution. Describe how you know which solutions are
present by the condition of the eggs in the solutions.
Egg 1 in distilled water: ______________________________________________________
Egg 2 in 30% sucrose solution: ________________________________________________
Egg 3 in physiological saline solution: ___________________________________________
Experiment 2 – Blood Cells in Different Solutions
- Prepare slide 1 of sheep’s blood in physiological saline solution and observe under microscope.
- Prepare slide 2 of sheep’s blood and a more concentrated saline solution and observe.
- Prepare slide 3 of sheep’s blood and distilled water and observe.
- How do the blood cells on slides 2 and 3 compare with those on slide 1?
__________________________________________________________________________
- Explain what happened to the blood cells on slides 2 and 3.
__________________________________________________________________________
PhysioEx Lab 5B – Insert the PhysioEx CD-Rom in a computer, select “Cell Transport” from
the drop down menu, and complete lab activities 1-5.
Define the following terms used in this lab:
Solute ________________________________________________________________________
Solvent _______________________________________________________________________
Solution ______________________________________________________________________
Hypotonic solution ______________________________________________________________
______________________________________________________________________________
Isotonic solution ________________________________________________________________
______________________________________________________________________________
Hypertonic solution _____________________________________________________________
______________________________________________________________________________
Homework: Complete the Lab 5A & 5B Review Sheets.