Question

Which pre-mRNA processing step is important for initiating translation?

a. poly-A tail

b. RNA editing

c. splicing

d. 7-methylguanosine cap

Short answer

After transcription, eukaryotic pre-mRNAs must go through numerous rounds of processing before they can be translated. TRNAs and rRNAs are also processed because they are essential components of the protein production machinery. As a result, option is the proper response (d).

Step-by-step solution

step-1: Introduction

mRNA is produced during the transcription process, when an enzyme called RNA polymerase turns the gene into main transcript mRNA (also known as pre-mRNA). Introns, or sections of the pre-mRNA that will not code for the final amino acid sequence, are generally still present.

step-2: Explanation of correct answer

'7-methylguanosine cap' is the option (d). Every mRNA molecule has a 7-methylguanosine cap, which shields the molecule from exonucleases that breakdown it. The cap is recognized by protein synthesis factors that aid in the initiation of the translation process in ribosomes. As a result, this choice is right.

step-3: Explanation of incorrect answers

'Poly-A tail' is the name given to option (a). The ploy-A tail yields a single mRNA molecule that can be translated. The production of the tail is not a stage in the translation process. As a result, this choice is incorrect.

'RNA editing' is the option (b). If multiple U nucleotides are missing from the mRNA, the cell performs an additional RNA processing step known as RNA editing. This is the incorrect option.

Option (c) is referred to as 'splicing.' Splicing is the process of removing introns and linking exons. It is carried out after the RNA has been transcribed. This is the incorrect option.