Final answer:
Cells synthesizing steroid hormones have a high concentration of smooth endoplasmic reticulum for lipid processing, while cells that secrete proteins have a prominent Golgi apparatus for protein packaging. Steroid hormones diffuse through cell membranes and regulate gene expression by forming hormone-receptor complexes.
Step-by-step explanation:
Cells that synthesize steroid hormones, such as cortisol or sex hormones, differ from cells that synthesize secretory proteins in several ways, primarily in their cellular organelle content. Cells producing steroid hormones will have an increased concentration of smooth endoplasmic reticulum (ER) because steroid hormones are lipid-derived and synthesized through the smooth ER. In contrast, cells that are active in secreting proteins, like those in salivary glands or immune cells, will have a well-developed Golgi apparatus to process and package secretory proteins for export out of the cell.
Once synthesized, steroid hormones freely diffuse across the lipid bilayer of target cells due to their hydrophobic nature. They bind to intracellular receptors in the cytoplasm or nucleus to form a hormone-receptor complex that acts as a transcription regulator. This complex then binds DNA in the nucleus and regulates gene expression, controlling the synthesis of particular mRNA and hence the protein produced.