Given below are two statements:

Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.

Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.

In the light of the above statements, choose the most appropriate answer from the options given below:

The correct option is Statement I is incorrect but statement II is correct.

Let's analyze both statements step-by-step to understand the biological mechanisms behind them:

Analysis of Statement I: "Transfer RNAs and ribosomal RNA do not interact with mRNA."
During the process of translation (protein synthesis), both transfer RNA (tRNA) and ribosomal RNA (rRNA) must interact directly with messenger RNA (mRNA):
- tRNA-mRNA Interaction: Each tRNA molecule carries a specific amino acid and contains an anticodon loop. This anticodon base-pairs specifically with the complementary codon on the mRNA template, ensuring the correct sequence of amino acids is added to the growing peptide chain.
- rRNA-mRNA Interaction: Ribosomes consist of proteins and ribosomal RNA (rRNA). The rRNA in the small ribosomal subunit plays a critical role in binding and aligning the mRNA. For example, in prokaryotes, the 16S rRNA binds directly to the Shine-Dalgarno sequence on the mRNA to initiate translation. In eukaryotes, the rRNA-containing subunit is crucial for scanning and positioning the mRNA during initiation.
Since both tRNA and rRNA actively interact with mRNA, Statement I is incorrect.

Analysis of Statement II: "RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence."
RNA interference (RNAi) is a gene-silencing process where double-stranded RNA molecules mediate the degradation of homologous single-stranded mRNAs. This process is a highly conserved eukaryotic mechanism that serves as a vital method of cellular defense against viral infection and the transposition of parasitic mobile genetic elements (transposons).
Since this mechanism is universal across eukaryotes for defense, Statement II is correct.

Therefore, Statement I is incorrect but Statement II is correct.