Sequence of DNA that is not involved in coding for a protein is called:

• A. Introns
• B. Exons
• C. Promoters
• D. Operators

Answer: (A)

Introns are the parts of a gene that are transcribed into RNA but not used to make the protein. They are removed during RNA processing (splicing) before the final mRNA is translated, so they don’t contribute to the amino acid sequence of the protein. Exons, on the other hand, are the sequences that remain in the mature mRNA and are translated into protein. Promoters are DNA regions that help start transcription by recruiting RNA polymerase, but they are not themselves translated into protein. Operators are regulatory DNA sequences in operons that bind repressors or activators to control transcription, also not translated. So introns are the sequences not involved in coding for a protein.