Select the BEST answer from the given options. Only one answer is correct. (Tip: treat each option as a true/false statement and read each question carefully!)

1. Physiological roles of hormones include:

   1.   ?    control of the synthesis & secretion of other hormones
   2.   ?    modulation of muscle contraction & relaxation
   3.   ?    control of reproductive processes
   4.   ?    all of the above
   5.   ?    none of the above

2. Which statement provides the best physiological definition of "half-life"?

   1.   ?    a video game in which you fight off an alien invasion of Earth
   2.   ?    the time it takes for the concentration of a hormone to fall to ½ of its initial levels
   3.   ?    the concentration of the hormone that produces a half-maximal response
   4.   ?    all of the above
   5.   ?    none of the above

3. A dose-response curve:

   1.   ?    illustrates how the hormone response changes with varying concentrations of the hormone
   2.   ?    will shift to the right with a decrease in tissue sensitivity to a hormone
   3.   ?    will have a lower maximal level with increased tissue responsiveness to a hormone
   4.   ?    two of the above
   5.   ?    all of the above

4. Peptide hormones:

   1.   ?    are synthesized on demand
   2.   ?    bind to receptors on target cell membranes
   3.   ?    usually require a transporter to travel through the blood
   4.   ?    all of the above
   5.   ?    none of the above

5. Peptide hormones are not capable of activating genes to stimulate or inhibit protein synthesis.

   1.   ?    true
   2.   ?    false

6. Steroid hormones:

   1.   ?    are derived form cholesterol by enzymatic modifications
   2.   ?    may activate second messenger systems to increase or decrease protein activity
   3.   ?    usually bind to receptors located in cytoplasm or nucleus of target cell
   4.   ?    all of the above
   5.   ?    none of the above

7. To create a standard curve for a radioimmunoassay to measure a hormone you need:

   1.   ?    an antibody specific to the hormone
   2.   ?    known amounts of radioactively labeled hormone
   3.   ?    known amounts of non-radioactively labeled hormone
   4.   ?    two of the above
   5.   ?    all of the above

8. Which of the following are shared characteristics of the nervous system and the endocrine system?

   1.   ?    some peptides are released both by neurons and endocrine cells
   2.   ?    both systems can secrete compounds into the blood
   3.   ?    both neurons and endocrine cells exhibit electrical activity
   4.   ?    all of the above
   5.   ?    none of the above

9. Synergism occurs when :

   1.   ?    a hormone opposes the actions of another hormone
   2.   ?    when the interaction of two hormones produces a response that is greater than the sum of the effects of the two hormones individually
   3.   ?    one hormone controls the secretion of another hormone
   4.   ?    full activation by a hormone requires the presence of a second hormone
   5.   ?    none of the above

10. The hormone melatonin is derived from:

    1.   ?    tyrosine
    2.   ?    tryptophan
    3.   ?    arginine
    4.   ?    arachidonic acid
    5.   ?    cholesterol

11. The catecholamines are derived from:

    1.   ?    tyrosine
    2.   ?    cholesterol
    3.   ?    linolenic acid
    4.   ?    opiods
    5.   ?    none of the above

12. External stimuli such as temperature do not have effects on hormone secretion.

    1.   ?    true
    2.   ?    false

13. The regular oscillatory cycles that produce circadian rhythms are generated by cells in the suprachiasmatic nucleus of the hypothalamus.

    1.   ?    true
    2.   ?    false

14. Regarding the genetic basis of the circadian rhythm in cells of the SCN:

    1.   ?    the genes period and time are expressed only at night
    2.   ?    the protein product of the genes dclock and cycle activates transcription of period and time genes
    3.   ?    the protein product of the genes period and time activates transcription of dclock and cycle genes
    4.   ?    all of the above
    5.   ?    none of the above

15. Sensitivity refers to the concentration of a hormone that produces a half-maximal response.

    1.   ?    true
    2.   ?    false