In eukaryotes, the regulation could be exerted at -
(A) Transcriptional level (formation of primary transcript)
(B) Processing level (regulation of splicing)
(C) Transport of mRNA from nucleus to the cytoplasm
(D) Translational level
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A), (B), (C) and (D)
Gene expression is the making of a polypeptide from the information in a gene. In eukaryotes this passes through several stages, and the cell can control it at each of them.
(A) Transcriptional level (formation of primary transcript) Correct. The cell controls whether and how much a gene is copied into RNA.
(B) Processing level (regulation of splicing) Correct. The primary transcript (hnRNA) is processed: introns are removed and exons are joined (splicing). Control here decides which mRNA is formed.
(C) Transport of mRNA from nucleus to the cytoplasm Correct. In eukaryotes the mRNA is made in the nucleus but used in the cytoplasm. Controlling its exit controls how much protein is made.
(D) Translational level Correct. Even after mRNA reaches the cytoplasm, the cell can control its translation into protein on the ribosomes.
NCERT Extract:
Regulation of Gene Expression –
