Identify the correct statement

To identify the correct statement, let us analyze each of the given options step-by-step:

1. Statement 1: "In capping, methyl guanosine triphosphate is added to the 3' end of hnRNA"
During the post-transcriptional processing of eukaryotic heterogeneous nuclear RNA (hnRNA), capping occurs at the 5' end. Specifically, an unusual nucleotide, methyl guanosine triphosphate (7-methylguanosine or 7-mG), is added to the 5' end of hnRNA, not the 3' end. The 3' end undergoes tailing (polyadenylation). Therefore, this statement is incorrect.

2. Statement 2: "RNA polymerase binds with Rho factor to terminate the process of transcription in bacteria."
In bacteria (prokaryotes), transcription termination can be dependent on a specific protein called the Rho (ρ) factor. The RNA polymerase enzyme associates transiently with the Rho factor, which helps in terminating transcription and releasing the newly synthesized RNA transcript. Therefore, this statement is correct.

3. Statement 3: "The coding strand in a transcription unit is copied to an mRNA."
During transcription, the template strand (which runs in the 3' to 5' direction) is read by RNA polymerase to synthesize mRNA. The coding strand (which runs in the 5' to 3' direction) has the same sequence as the newly synthesized mRNA (except with thymine instead of uracil) and is not directly copied. Therefore, this statement is incorrect.

4. Statement 4: "Split gene arrangement is characteristic of prokaryotes."
Split gene arrangement, where genes contain both coding regions (exons) and non-coding regions (introns), is a characteristic feature of eukaryotes, not prokaryotes. Prokaryotic genes are typically continuous and lack introns. Therefore, this statement is incorrect.

Conclusion: The only biologically accurate statement is that RNA polymerase binds with the Rho factor to terminate the process of transcription in bacteria.