Question

Wait, if the steroids can enter any cell, how is specificity of action possible?

(A) Steroids will only cause an effect in cells with their intracellular receptors expressed.
(B) Steroids will only cause an effect in cells with their intracellular receptors coded for in the cell's DNA.
(C) Steroids are meant to cause an effect in all cells, so specificity is not an issue.
(D) This is false. Only certain cell membranes are permeable to steroids.

Answer 1

Steroid hormones are specific in their action because they only affect cells that have the corresponding intracellular receptors. These receptors allow the steroid hormone to regulate the transcription of specific genes within the target cell. The correct option is b.

Step-by-step explanation:

The specificity of action in steroid hormones is achieved because steroids will only cause an effect in cells that have the appropriate intracellular receptors expressed within them. Once a steroid hormone crosses the plasma membrane, it binds with its specific intracellular receptor, forming a hormone-receptor complex. This complex then moves to the cell nucleus where it binds to certain segments of the cell's DNA, regulating the transcription of specific genes and hence affecting protein synthesis. This mechanism ensures that each steroid hormone exerts its influence only on target cells equipped with the necessary receptor proteins. The correct answer to the original question is (A) Steroids will only cause an effect in cells with their intracellular receptors expressed because this is how specificity of action is maintained.