Question

In split genes, the coding sequences are called

• A. Operons
• B. Introns
• C. Cistrons
• D. Exon

Answer 1

The correct option is D Exon

Introduction to split genes
1) In eukaryotes, both introns and exons are present in a gene. This arrangement is called split gene.
2) During the formation of a functional mRNA molecule, the introns are spliced off.

Exons
Exons are the coding sequences of a split gene. During transcription, exons are transcribed into the RNA transcript.

Introns
Introns are non-coding sequences which are also transcribed into the primary RNA transcript or hnRNA. However, before transporting the hnRNA to the cytoplasm, the introns are removed and exons are joined by the process of splicing.

Cistron
Cistron is a part of a gene that codes for a polypeptide.
In prokaryotic cells, it is made up of exons (coding segments). In eukaryotic cells it is made up of both exons and introns (non-coding segments).

Operon
Operon is a coordinated group of regulatory and structural genes that function together as a unit to control the formation of protein.

Final answer
(A) Exons