Biology, Eighth Edition (Raven)

Chapter 16: Control of Gene Expression

Action of Glucocorticoid Hormone

Are genes turned on or off permanently in each cell? Gene expression varies between cells. A muscle cell will express different genes than a white blood cell even though both cells have identical genomes. Gene expression varies over time as well. Signals from other parts of the body can temporarily turn on or off specific genes in response to environmental conditions. By modifying gene expression organisms can respond to changes inside and outside of the body. While some genes may be turned on or off permanently at the time that the basic phenotype of the cell is determined, other genes are dynamic and change expression continuously in response to the local environment.

View the animation below, then complete the quiz to test your knowledge of the concept.


Glucocorticoid hormones activate genes that are involved in which of the following processes?
A)synthesis of glucose
B)mobilization of fats
C)breakdown of proteins
D)A and B
E)A, B and C

Glucocorticoids are ________ hormones secreted by ________ glands.
A)peptide ; endocrine
B)peptide ; exocrine
C)steroid ; endocrine
D)steroid ; exocrine
E)None of the above is true

Arrange the following in the proper order in which they occur during glucocorticoid hormone action.

1. Binding of hormone to receptor
2. Release of HSP90 proteins
3. Entry of hormone into the nucleus
A)1, 2, 3
B)2, 1, 3
C)2, 3, 1
D)3, 2, 1
E)3, 1, 2

Glucocorticoid response elements function as enhancers.

The glucocorticoid receptor is active as a dimer.
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