Steroid hormones can enter a cell by simple diffusion. Therefore, steroids __________.

• A. are not an example of signaling molecules
• B. do not bind to receptors
• C. directly bind to DNA
• D. act by phosphorylating DNA
• E. do not initiate cell signaling by interacting with a receptor in the plasma membrane

Answer: (E)

Verified step by step guidance

1. Understand the nature of steroid hormones: Steroid hormones are lipophilic, meaning they can easily pass through the lipid bilayer of cell membranes by simple diffusion.
2. Recognize the mechanism of action: Unlike peptide hormones, which bind to receptors on the cell surface, steroid hormones typically enter the cell and bind to intracellular receptors.
3. Identify the location of action: Once inside the cell, steroid hormones often bind to receptors in the cytoplasm or nucleus, forming a hormone-receptor complex.
4. Explore the function of the hormone-receptor complex: This complex can directly interact with DNA, influencing gene expression by acting as a transcription factor.
5. Clarify the signaling process: Since steroid hormones do not require a receptor on the plasma membrane to initiate signaling, they do not initiate cell signaling by interacting with a receptor in the plasma membrane.