Question

Which of the following is not correct :-

• A. Heterogeneous nuclear RNA (hn RNA) are the smallest molecules which carry amino acids to the site of protein synthesis.
• B. Temin and Baltimore reported reversal of central dogma, by discovering reverse transcription in some viruses.
• C. In transcription only a segment of DNA and only one of the strands is copied into RNA.
• D. The coding DNA sequence of the gene are called exons and the intervening non-coding DNA sequences are called introns.

Answer 1

The correct option is A Heterogeneous nuclear RNA (hn RNA) are the smallest molecules which carry amino acids to the site of protein synthesis.

A. Split genes are the genes that have protein coding regions (exons) interrupted by the presence of non-coding DNA segments (introns). The exons are transcribed into RNA and finally translated into proteins. Introns are the interrupting sequences that do not code for any protein products.

B. The discovery of reverse transcriptase in retroviruses by David Baltimore and Howard Temin.

C. hnRNA undergoes additional processing called as capping and tailing. In capping an unusual nucleotide (methyl guanosine triphosphate) is added to the 5'-end of hnRNA. In tailing, adenylate residues (200-300) are added at 3'-end in a template independent manner. It is the fully processed hnRNA, called mRNA that is transported out of the nucleus for translation.

D. The process of copying genetic information from one strand of the DNA into RNA is termed as transcription.

So, the correct answer is "option C"