Which of the following is a characteristic shared by both steroid hormones and amino acid-based hormones?

• A. They both act exclusively through intracellular receptors.
• B. They are both water-soluble and circulate freely in the bloodstream.
• C. They both bind to specific receptors to initiate a cellular response.
• D. They are both derived from cholesterol.

Answer: (C)

Verified step by step guidance

1. Understand the two main types of hormones: steroid hormones and amino acid-based hormones. Steroid hormones are lipid-soluble and derived from cholesterol, while amino acid-based hormones are typically water-soluble and derived from amino acids or peptides.
2. Recognize the key difference in how these hormones interact with receptors. Steroid hormones usually pass through the cell membrane and bind to intracellular receptors, while amino acid-based hormones bind to receptors on the cell surface.
3. Focus on the shared characteristic mentioned in the problem: both types of hormones bind to specific receptors to initiate a cellular response. This is a universal feature of hormone action, regardless of the type.
4. Eliminate incorrect options based on your understanding: (1) Steroid hormones act through intracellular receptors, but amino acid-based hormones do not exclusively do so. (2) Steroid hormones are not water-soluble, so they do not circulate freely in the bloodstream like amino acid-based hormones. (4) Only steroid hormones are derived from cholesterol, not amino acid-based hormones.
5. Conclude that the correct answer is the shared characteristic: 'They both bind to specific receptors to initiate a cellular response.' This is the fundamental mechanism by which hormones exert their effects on target cells.