Describe the primary mechanism by which antibiotic resistance genes are transferred between bacterial cells.

The primary mechanism for the transfer of antibiotic resistance genes between bacterial cells is horizontal gene transfer, which can occur via conjugation, transformation, or transduction: 1. Conjugation: Direct transfer of genetic material, typically plasmids carrying resistance genes, between two bacteria through a sex pilus. 2. Transformation: Uptake of free DNA containing resistance genes from the environment. 3. Transduction: Transfer of resistance genes from one bacterium to another via a bacteriophage (virus).