Alternative splicing refers to splicing of introns in a pre-mRNA that occurs in different ways, leading to different mRNAs that code for different proteins.

Alternative splicing refers to splicing of introns in a pre-mRNA that occurs in different ways, leading to different mRNAs that code for different proteins.

• A. Splicing of exons in a single way to form one protein.
• B. Splicing of introns in different ways to produce different mRNAs.
• C. Splicing out all introns and exons together.
• D. Splicing mRNA in the nucleus to degrade it.

Answer: (B)

Alternative splicing is the process by which a single gene can produce multiple mRNA transcripts by joining exons in different combinations after transcription. This happens during pre-mRNA processing in the nucleus, where different splice sites can be used, leading to inclusion or skipping of certain exons and sometimes alternative splice sites. The result is multiple mature mRNA molecules from the same gene, each potentially encoding a different protein variant. The option describing splicing introns in different ways to produce different mRNAs captures this idea directly: varying the splicing pattern yields distinct mRNA isoforms, which then code for different proteins. The other descriptions don’t fit. Splicing exons in a single way to form one protein refers to constitutive splicing, not alternative splicing. Splicing out all introns and exons together isn’t how splicing works—introns are removed while exons are joined in specific ways. Splicing mRNA in the nucleus to degrade it describes a degradative process, not the normal production of mature, translatable mRNA.

Alternative splicing is the process by which a single gene can produce multiple mRNA transcripts by joining exons in different combinations after transcription. This happens during pre-mRNA processing in the nucleus, where different splice sites can be used, leading to inclusion or skipping of certain exons and sometimes alternative splice sites. The result is multiple mature mRNA molecules from the same gene, each potentially encoding a different protein variant.

The option describing splicing introns in different ways to produce different mRNAs captures this idea directly: varying the splicing pattern yields distinct mRNA isoforms, which then code for different proteins.

The other descriptions don’t fit. Splicing exons in a single way to form one protein refers to constitutive splicing, not alternative splicing. Splicing out all introns and exons together isn’t how splicing works—introns are removed while exons are joined in specific ways. Splicing mRNA in the nucleus to degrade it describes a degradative process, not the normal production of mature, translatable mRNA.