Question

MRNA splicing: Which of the following statements is true?

1) Can be used to produce several different proteins at times or in different cell types from a single pre-mRNA
2) Universal step in processing in pre-mRNAs produced by all cell types
3) Mechanism by which exons are removed from eukaryotic pre-mRNAs
4) An auto catalytic process of the pre-mRNA
5) Occurs in the nucleus of eukaryotic cells but in the cytoplasm nucleolus region in prokaryotes

Answer 1

The true statement about mRNA splicing is that it can produce several different proteins from a single pre-mRNA in various cell types or at different times. This is known as alternative RNA splicing and is a common mechanism of gene regulation in eukaryotes.Option A is the correct answer.

Step-by-step explanation:

The process of mRNA splicing can be described as follows:

1. Alternative RNA Splicing: It is a mechanism that allows a single pre-mRNA to be spliced in various ways to produce different proteins. This can depend on the cell type or stage of development, and is a common mechanism of gene regulation in eukaryotes.
2. Splicing is a step in processing pre-mRNAs that is not universal across all cell types, as it occurs in eukaryotic cells but not in prokaryotes.
3. The process involves the removal of introns and precisely rejoining exons. It is not about removing exons, and the order of exons is always conserved.
4. Splicing is conducted by complexes of proteins and RNA molecules called spliceosomes, and is not an autocatalytic process of the pre-mRNA itself.
5. The process of splicing occurs in the nucleus of eukaryotic cells and does not take place in prokaryotes, as they do not have a nucleus.

Therefore, the statement that is true is the first one: mRNA splicing can be used to produce several different proteins from a single pre-mRNA, depending on the time and cell type.