Question

In split genes, the coding sequences are called as

A. Cistrons

B. Operons

C. Exons

D. Introns

Answer 1

Hint: In an interrupted gene, the total gene is split into a few parts which include the coding region and the non-coding region. The coding region of a gene or DNA is also called the CDS. It is the part of the DNA or RNA of the gene that codes for proteins.

Complete answer: 

The split genes are genes that possess the protein-coding regions known as exons which are interrupted by the presence of non-coding DNA sequence segments known as introns. These are transcribed into RNA or DNA and then translated into proteins. Exons are the actual protein-coding regions in a DNA or an RNA sequence. In such genes, the introns are removed by a process called splicing and the exons are joined together. Such genes can be seen in eukaryotes.

A. A cistron is an alternative term for a gene. It is a segment of DNA that codes for a polypeptide, both the structural sequences and the regulatory sequences.

B. An operon is a group or a system of genes that are regulated by the promoter. It contains the operator gene and the structural gene.

C. An intron is a nucleotide sequence in a gene which is removed from the DNA or RNA sequence by the process of splicing after the maturation of the RNA OR DNA before translation.

So, the correct answer is option (C).

Additional information: An intron is a vital part of a DNA or RNA sequence as the protein quality or type is significantly determined by the splicing process in which the introns play significant roles. Splicing produces many different proteins from a single gene in a eukaryotic cell.

Note: Gene splicing is the method of cutting the DNA using enzymes to add nitrogenous bases to the DNA sequence. The DNA is cut by using specific enzymes known as restriction enzymes. Gene splicing includes the removal of introns from the original sequence of an uneven gene in the process of transcription.