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Venom!

Instructional Objectives
Background Information
Activity
Procedures
Evaluation
Extension for Lower Grades


Topic: Neutralizing a Venom

Instructional Objectives:

Students will:

  1. Learn about the nature of venom and the treatment of envenomation.
  2. Conduct an experiment to demonstrate how proteins such as venoms can be denatured.

Background Information:

Toxicologists report that venoms represent some of the most complex chemical compounds in nature.

There are many fish species with spines capable of injecting venom. This ability is nearly always a protective mechanism, but is occasionally used for incapacitating prey. The spines may be concealed, as in the stonefish, or displayed, as in the lionfish, as a warning to predators.

Many venoms are actually proteins and as such can be denatured through special techniques including heat treatment.

Please refer to the Secrets of the Ocean Realm episode "Venom!" for more information about venomous fish.

Activity: Denaturing a Protein

Time Needed For Activity: One 20-minute period

Target Grade Level: High School

Materials:

  • raw eggs
  • glass beakers
  • table spoons
  • heated water
  • compresses

Procedures:

  1. Break an egg into a beaker and remove the yolk using a table spoon. (Tilt the beaker in order to make removal easier).
  2. Save the white in the beaker. This white, a protein compound, will be used to represent the venom of a marine animal.
  3. Now, using volunteers from among the students, carefully pour the "venom" onto the backs of hands or arms. (These limbs are the ones most commonly envenomated during accidental contact with marine animals.)
  4. After soaking the compresses in hot water (not scalding!) apply the hot compresses to the envenomated areas. After a few moments, remove the compresses and observe the results. What has happened to the "venom?" Is it now more readily removed from the limb?

Evaluation:

What the students have succeeded in demonstrating is the recommended treatment for a marine envenomation. Most fish venoms, being proteins, are readily denatured by the application of heat. In much the same way the egg white solidifies when heated, venoms coagulate under heat treatment. This coagulation inhibits their circulation under the skin, in the case of punctures by spines or injections by fangs, and allows their ready removal in the case of surface stings such as delivered by jellyfish and corals.


Extension for Lower Grades:

Venomous animals are common among insects, fishes, amphibians, and reptiles. There are no venomous birds, and only one venomous mammal-the duckbill platypus of Australia. (The latter has venom glands in its hind legs and delivers its venom by scratching with specially adapted claws.) Assign students into groups for each of the four groups of animals mentioned in the first sentence. Let each student choose an example or examples from these groups to report on. (Allow up to one week for library or other research.) Have students consider the potency of venoms, how the animals deliver them, and what their purposes are.


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