NOVA scienceNOW: Obesity

Student Handout

Hormones and Receptors

Hormones are the body's chemical messengers. They typically travel through the bloodstream and initiate a response in cells (called target cells) far from where the hormones were made. To enter a target cell, a hormone binds to specific receptors on the cell. In this activity, you will make hormone-receptor models, use them to understand specific mutations, and then assess each model's strengths and limitations.

Procedure

1. Assemble the three hormone-receptor models illustrated on your Model Diagrams handout.

2. For each model, label the following parts: hormone, plasma membrane, cytoplasm, and hormone receptor.

3. Write a possible outcome or consequence of the following mutations or conditions.

   • A mutation alters the amount of hormone produced:

     _________________________________________________________

   • A mutation prevents a hormone from binding to the receptor:

     _________________________________________________________

   • There is no cell or tissue to produce a hormone:

     _________________________________________________________

4. Design your own hormone-receptor model. List your materials and draw and label your model in Box 4 of the Model Diagrams handout.

5. In the table below, write at least two strengths and two limitations of each model system.

   	Model 1	Model 2	Model 3	Model 4
   Strengths
   Limitations

Questions
Write your answers on a separate sheet of paper.

1. Which model best represents a hormone-receptor system? Why?

   For Questions 2-4, refer to the gene mutations and conditions addressed in Step 3 above.

2. Which mutation or condition might be "corrected" by hormone injection?

3. Which mutation or condition might respond to a transplant of the tissue that could produce the needed hormone?

4. Which mutation or condition would most likely respond to gene therapy (i.e., injecting genes that can help the body produce functional products)?