Question

The fully processed hnRNA is called as (i) and its transported out of the (ii) into the (iii) for translation.
A. (i)mRNA, (ii)nucleus, (iii)cytoplasm.
B. (i) mRNA, (ii) cytoplasm, (iii) nucleus.
C. (i) tRNA, (ii) cytoplasm, (iii) nucleus.
D. (i) tRNA, (ii) nucleus, (iii) cytoplasm.

Answer 1

Hint: An extrachromosomal RNA molecule or unprocessed mRNA refers to the large pre-mRNAs of different nucleotide sequences produced by RNA Polymerase II that serve as the primary transcript of DNA.

Complete answer:
Option A is correct. A term that encompasses different types and sizes of RNAs found in the eukaryotic cell nucleus is heterogeneous nuclear RNA or hnRNA. As this is modified and processed, the mature mRNA that has the inherent protein synthesis code (amino acid code) can give rise to this. In the nucleus, the mRNA in eukaryotes is synthesised and should therefore be transported through the translation mechanism to the cytoplasm and into the ribosome for protein synthesis.
Option B is incorrect. There are both introns and exons present in the nucleus in the precursor of mRNA, i.e., hnRNA. The transport of mRNA via the translation process to the cytoplasm from the nucleus to the cytoplasm and into the protein synthesis ribosome.
Option C is incorrect. tRNA (Transfer ribonucleic acid) is a type of RNA molecule that helps decode a sequence of messenger RNA (mRNA) into a protein. During translation, tRNAs act at specific sites in the ribosome, which is a mechanism that synthesises a protein from an mRNA molecule. A special protein that reads the DNA code and makes a copy of the RNA, or pre-tRNA, is made. This method is called transcription, and it is performed by RNA polymerase III to make tRNA. When they leave the nucleus, Pre-tRNA is stored.
Option D is incorrect. In the fluid within cells (the cytoplasm), cytoplasmic tRNAs are contained. These tRNAs help generate proteins in the nucleus of the cell (nuclear DNA) from genes that are located in the DNA. Cellular structures called mitochondria have a limited amount of their own DNA, called mitochondrial DNA, while most DNA is nuclear.

So, the correct answer is Option A.

Note: The pre-mRNA molecules that need extensive processing to become mature mRNA molecules are largely composed of hnRNA. The heterogeneous nuclear ribonucleoprotein (hnRNP) is formed by the protein-associated hnRNA. By allowing them to form a special secondary structure, HnRNP proteins stabilise pre-mRNAs. Throughout the pre-mRNA, various hnRNP proteins identify and bind to various sequences.