[Campbell Biology P.427] Based on Figure 18.14 and the accompanying text, which statement ac... | Practice Question

Based on Figure 18.14 and the accompanying text, which statement accurately describes alternative RNA splicing?

  • A: It produces different primary RNA transcripts from a single gene.
  • B: It involves the selective inclusion or exclusion of exons from a primary transcript.
  • C: It occurs exclusively in prokaryotic cells to increase protein diversity.
  • D: It primarily regulates gene expression by modifying chromatin structure.

Explanation

Alternative RNA splicing is a process that occurs in eukaryotic cells, where different combinations of exons from a single primary RNA transcript are joined together to form multiple distinct mRNA molecules. This mechanism significantly expands the protein repertoire of an organism from a limited number of genes. Figure 18.14 clearly illustrates how a single troponin T gene primary transcript can yield two different mRNA molecules by selectively including exon 3 or exon 4, leading to different but related muscle proteins. The text further emphasizes that this regulation occurs at the RNA processing level and is controlled by cell-type-specific regulatory proteins.