Final answer:
Steroid hormones are synthesized in the smooth endoplasmic reticulum and mitochondria. They diffuse through plasma membranes due to their lipid-soluble nature and bind to intracellular receptors, influencing gene expression.
Step-by-step explanation:
Steroid hormones are synthesized in the smooth endoplasmic reticulum (smooth ER) and mitochondria of intracellular compartments. These hormones are fat soluble and derived from cholesterol, allowing them to readily diffuse through the lipid bilayer of cell membranes. Once they have crossed the plasma membrane, they bind with intracellular receptors either in the cytoplasm or directly in the nucleus.
Upon entering the cell, a steroid hormone and its receptor form a complex that can move into the nucleus where it influences the expression of genes. This action essentially turns the complex into a transcription factor, regulating gene expression and affecting protein synthesis. This process is vital for the regulation of numerous physiological processes, making steroid hormones crucial for maintaining homeostasis within the body.