Match List-I with List-II
| List-I | List-II |
|---|---|
| Terms | Features |
| (A) Cistron | (I) Intervening sequences absent in processed RNA |
| (B) Monocistronic | (II) Coding sequences or expressed sequences of RNA |
| (C) Exon | (III) Segment of DNA coding for a polypeptide |
| (D) Intron | (IV) Structural gene in a transcription unit |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A) - (III), (B) - (IV), (C) - (II), (D) - (I)
(A) Cistron — this matches (III) Segment of DNA coding for a polypeptide. A cistron is the unit of DNA that carries the information for one polypeptide.
(B) Monocistronic — this matches (IV) Structural gene in a transcription unit. In a monocistronic transcription unit the structural gene has a single cistron, so one polypeptide is made. Most eukaryotic genes are of this kind. Bacterial genes are often polycistronic.
(C) Exon — this matches (II) Coding sequences or expressed sequences of RNA. Exons are the parts that stay in the processed RNA and are expressed.
(D) Intron — this matches (I) Intervening sequences absent in processed RNA. Introns lie between the exons. They are cut out by splicing, so they are absent from the processed RNA.
NCERT Extract:
Transcription Unit and the Gene – “… However by defining a cistron as a segment of DNA coding for a polypeptide, the structural gene in a transcription unit could be said as monocistronic (mostly in eukaryotes) or polycistronic (mostly in bacteria or prokaryotes). In eukaryotes, the monocistronic structural genes have interrupted coding sequences – the genes in eukaryotes are split. The coding sequences or expressed sequences are defined as exons. Exons are said to be those sequence that appear in mature or processed RNA. The exons are interrupted by introns. Introns or intervening sequences do not appear in mature or processed RNA.”