In pBR322 cloning vector, rop codes for the proteins involved in the __________ of the plasmid.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Replication
pBR322 is an E. coli cloning vector, a plasmid used to carry a foreign gene into a host cell. It has an origin of replication (ori), two antibiotic resistance genes (ampR and tetR) used as selectable markers, several restriction sites, and the rop gene. The rop gene codes for proteins that help the plasmid replicate.
(1) Translation — Incorrect. Translation is the making of protein on the ribosome. rop codes for proteins, but these do not carry out translation.
(2) Transcription — Incorrect. Transcription is the making of RNA from DNA. It is not the job of the Rop proteins.
(3) Replication — Correct. The Rop proteins are involved in copying the plasmid.
(4) Transduction — Incorrect. This is the transfer of bacterial genes by a virus. The plasmid proteins have no such role.
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