Final answer:
Steroid molecules diffuse into the cell via simple diffusion, moving passively from higher to lower concentration without the need for transport proteins or cellular energy.
Step-by-step explanation:
A steroid molecule would diffuse into the cell by simple diffusion. Steroid molecules are hydrophobic and can easily pass through the lipid bilayer of the cell membrane without the assistance of transport proteins, channels, or the expenditure of energy.
This is because they are small and generally nonpolar, which allows them to interact with the hydrophobic tails of the phospholipids in the cell membrane.
During simple diffusion, steroid molecules move from an area of higher concentration to one of lower concentration until equilibrium is reached. This is part of the passive transport processes, in which substances naturally diffuse across the membrane without cellular energy being used.
This process allows steroid hormones to effectively enter cells and mediate their functions, such as regulating gene expression.