Steroid hormones are a type of hormone that are derived from cholesterol and are known for their ability to pass through the cell membrane and bind to specific receptors inside the cell. Once inside the cell, steroid hormones influence cellular activities by binding to DNA and forming a gene-hormone complex.

The process by which steroid hormones influence cellular activities can be summarized in the following steps:

1. Diffusion through the cell membrane: Steroid hormones are lipophilic molecules, meaning they can easily pass through the lipid bilayer of the cell membrane. This allows them to enter the cell and interact with their target receptors.

2. Binding to intracellular receptors: Once inside the cell, steroid hormones bind to specific intracellular receptors, which are typically found in the cytoplasm or nucleus. These receptors are specific to each type of steroid hormone.

3. Formation of a gene-hormone complex: The binding of the steroid hormone to its receptor triggers a conformational change in the receptor, allowing it to interact with specific DNA sequences. The hormone-receptor complex then binds to these DNA sequences, known as hormone response elements, on the target genes.

4. Transcriptional regulation: The binding of the gene-hormone complex to the hormone response elements on the DNA regulates the transcription of the target genes. This can result in either an increase or decrease in the expression of these genes.

5. Protein synthesis: The altered gene expression leads to the synthesis of specific proteins, which are responsible for carrying out various cellular activities. These proteins can be enzymes, transporters, receptors, or structural proteins, among others.

By directly influencing gene expression, steroid hormones have the ability to regulate a wide range of cellular activities, including metabolism, growth and development, reproduction, and immune function. The effects of steroid hormones are generally slow and long-lasting, as they involve changes in gene expression and protein synthesis.

In summary, steroid hormones influence cellular activities by binding to specific receptors inside the cell, forming a gene-hormone complex, and regulating gene expression. This allows them to control various cellular processes and contribute to the overall physiological functions of the body.