Most bioorganic substances (proteins, nucleic acids) contain electron-donor groups, including nitrogen, sulfur, oxygen. These groups form hydrogen bonds forming the tertiary structure of the protein. Heavy metals, interacting with these groups, destroy hydrogen bonds in protein molecules and disrupt the tertiary protein structure. The biological properties of the substance (activity, transport properties, processes of transcription and translation of nucleic acids) are changing. This is the carcinogenic and mutagenic effect of heavy metals.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.