Question

Genes in eukaryotic cells often have intron sequences coded for within the DNA. These sequences are ultimately not translated into proteins. Why?

A) Intron sequences are removed from RNA molecules by the spliceosome, which works in the nucleus.
B) Introns are not transcribed by RNA polymerase.
C) Introns are removed by catalytic RNAs in the cytoplasm.
D) The ribosome will skip over intron sequences when translating RNA into protein.

Answer 1

Intron sequences are not translated into proteins because they are removed by the spliceosome within the nucleus, ensuring only the coding sequences (exons) are joined together to form functional proteins.

Step-by-step explanation:

In eukaryotic cells, intron sequences coded within the DNA are ultimately not translated into proteins because intron sequences are removed from RNA molecules by the spliceosome. This removal occurs in the nucleus, ensuring that only the exons, which are the coding sequences, are expressed.

If introns were not precisely and completely removed, the exon sequences would be misjoined, leading to a dysfunctional polypeptide. This precise process is crucial for the proper synthesis of proteins, which is vital for the functionality of any cell. Introns may also play roles in gene regulation and mRNA transport, highlighting their importance beyond just being non-coding sequences.