Are all bacteria competent for transformation?

No, not all bacteria are naturally competent for transformation. Only specific species, such as Streptococcus pneumoniae, Bacillus subtilis, and Neisseria gonorrhoeae, have the genetic machinery and regulatory pathways for natural competence. However, bacteria that are not naturally competent can often be made artificially competent in the laboratory using chemical treatments (e.g., CaCl₂) or physical methods (e.g., electroporation).