An Interactive Introduction to Organismal and Molecular Biology, 2021
An Interactive Introduction to Organismal and Molecular Biology, 2021
An Interactive Introduction to Organismal and Molecular Biology, 2021
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18.<br />
PROTEIN SYNTHESIS II: RNA PROCESSING<br />
<strong>An</strong>drea Bierema<br />
Learning Objectives<br />
Students will be able <strong>to</strong>:<br />
• Describe the molecular ana<strong>to</strong>my of genes <strong>and</strong> genomes.<br />
• Describe exons <strong>and</strong> introns.<br />
• Explain how splicing occurs during mRNA processing.<br />
• Explain the process of alternative splicing.<br />
• Describe how alternative splicing contributes <strong>to</strong> cells having different functions.<br />
• Identify additional steps that take place during mRNA processing.<br />
Overview<br />
At the end of transcription, once the polymerase releases the RNA molecule, the RNA is not quite ready for<br />
translation <strong>and</strong> is not technically an “mRNA” yet. It still needs <strong>to</strong> be “processed,” which means that certain<br />
nucleotides are removed <strong>and</strong> others are added—at the end of this, it is an mRNA molecule, but before that, it is<br />
a pre-mRNA molecule. This occurs as the RNA molecule is leaving the nucleus. After it is processed, it is then<br />
ready for translation, which is covered in a future chapter. This chapter focuses on the different steps that take<br />
place during mRNA processing <strong>and</strong> how some of these steps allow for cells within a single organism <strong>to</strong> have<br />
different functions. Please see the previous chapter for a review of transcription.
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