Which of the following is an example of post-transcriptional control of gene expression?
a. The addition of methyl groups to cytosine bases of DNA
b. The binding of transcription factors to a promoter
c. The removal of introns and alternative splicing of exons
d. Gene amplification contributing to cancer

Verified step by step guidance

1. Understand that post-transcriptional control refers to the regulation of gene expression after the transcription process has occurred.
2. Recall that transcription is the process where the DNA sequence of a gene is copied into RNA.
3. Identify that post-transcriptional modifications include processes that occur to the RNA transcript after it is synthesized, such as splicing, editing, and transport.
4. Recognize that the removal of introns and alternative splicing of exons are processes that modify the RNA transcript after transcription, thus fitting the definition of post-transcriptional control.
5. Conclude that option c, 'the removal of introns and alternative splicing of exons,' is an example of post-transcriptional control of gene expression.

Key Concepts

Post-Transcriptional Control

Post-transcriptional control refers to the regulation of gene expression after the transcription of DNA to mRNA. This includes processes such as RNA splicing, editing, transport, and degradation. These mechanisms allow cells to modify mRNA molecules, influencing which proteins are produced and in what quantities, thus playing a crucial role in cellular function and adaptation.

RNA Splicing

RNA splicing is a process where introns, non-coding regions of a pre-mRNA transcript, are removed, and exons, coding sequences, are joined together. This process is essential for producing a mature mRNA molecule that can be translated into a protein. Alternative splicing allows a single gene to produce multiple protein variants, increasing the diversity of proteins a cell can produce.

Alternative Splicing

Alternative splicing is a mechanism by which different combinations of exons are joined together to produce multiple mRNA variants from a single gene. This process allows for the generation of diverse protein isoforms with potentially different functions from the same genetic sequence, contributing to the complexity of gene expression regulation and protein function in eukaryotic organisms.