Procedure Bosmosis

1. Review a textbook section on osmosis.

2. To demonstrate osmosis, refer to figure 5.2 as you follow these steps:

a. One person plugs the tube end of a thistle tube with a finger.

b. Another person then fills the bulb with molasses until it is about to overflow at the top of the bulb. Note that air remains trapped in the stem.

c. Cover the bulb opening with a single-thickness piece of moist selectively permeable (semipermeable) membrane. Dialysis tubing that has been soaked for 30 minutes can easily be cut open because it becomes pliable.

d. Tightly secure the membrane in place with several wrappings of a rubber band.

e. Immerse the bulb end of the tube in a beaker of water. If leaks are noted, repeat the procedures.

Figure 5.2 (a) Fill the bulb of the thistle tube with molasses; (b) tightly secure a piece of selectively permeable (semipermeable) membrane over the bulb opening; and (c) immerse the bulb in a beaker of water. Note: These procedures require participation of two people.

Figure 5.2 (a) Fill the bulb of the thistle tube with molasses; (b) tightly secure a piece of selectively permeable (semipermeable) membrane over the bulb opening; and (c) immerse the bulb in a beaker of water. Note: These procedures require participation of two people.

Selectively Semipermeable Membrane
(a) (b) (c)

f. Support the upright portion of the tube with a clamp on a ring stand. Folded paper under the clamp will protect the thistle tube stem from breakage.

g. Mark the meniscus level of the molasses in the tube. Note: The best results will occur if the mark of the molasses is a short distance up the stem of the thistle tube when the experiment starts.

h. Measure the level changes after 10 minutes and 30 minutes.

3. Complete Part B of the laboratory report.

three separate microscope slides marked 1, 2, and 3.

e. Cover the drops with coverslips and observe the blood cells, using the high power of the microscope.

3. Complete Part C of the laboratory report.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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