Final answer:
The transcription and translation of introns by mistake generally lead to the production of non-functional proteins due to reading frame disruptions and the potential inclusion of damaging amino acid sequences. Rare exceptions exist but are not typical. Mutations in other areas of translation machinery, like ribosomal RNA or transfer RNA, often result in defective or decreased protein production.
Step-by-step explanation:
If a cell transcribed and translated an intron by mistake, it would likely lead to the production of non-functional proteins. Introns are sequences within a gene that are removed during RNA splicing before translation. Including these normally non-coding regions in the final mRNA can disrupt the reading frame and result in a protein with a different amino acid sequence, potentially interfering with the protein's normal function. In the cases where the transcribed introns do not disrupt the reading frame, they may still lead to the incorporation of unnecessary and sometimes harmful sequences into the protein.
However, in rare instances, such as a transversion mutation in the introns leading to alternative splicing, a functional protein could potentially be produced. This is not the norm and is considered an exception to the standard process of gene expression.
Mutations affecting other components of the protein synthesis process, such as the ribosomal RNA (rRNA) or transfer RNA (tRNA), usually lead to defective proteins or decreased protein production. For example, a mutation rendering the 60S ribosomal subunit nonfunctional, or not adding the 5' methyl guanosine cap to an mRNA, could impede translation, affecting the overall protein synthesis within the cell.