MRNA

Definition

mRNA, or messenger RNA, is a type of RNA that carries genetic information from DNA to the ribosome, where proteins are synthesized. It plays a crucial role in the process of gene expression by serving as a template for translating the genetic code into a functional protein, thereby bridging the gap between the genetic blueprint and the functional products within a cell.

5 Must Know Facts For Your Next Test

1. mRNA is synthesized during transcription, where RNA polymerase reads the DNA template and creates a complementary RNA strand.
2. The sequence of nucleotides in mRNA is read in sets of three called codons, each specifying a particular amino acid to be added to the growing polypeptide chain.
3. After transcription, mRNA undergoes processing, including the addition of a 5' cap and a poly-A tail, which protect it from degradation and assist in translation.
4. In eukaryotic cells, mRNA is exported from the nucleus to the cytoplasm, where ribosomes translate it into proteins.
5. Different types of mRNA can have varying lifespans in a cell, influencing how long they can be translated into proteins and thereby affecting cellular functions.

Review Questions

• How does mRNA play a role in gene expression and what processes are involved from transcription to translation?
  • mRNA plays a central role in gene expression by serving as the intermediary between DNA and protein synthesis. During transcription, RNA polymerase synthesizes mRNA from the DNA template. Once produced, the mRNA undergoes processing before being transported out of the nucleus. In the cytoplasm, ribosomes read the mRNA sequence and translate it into proteins through the help of tRNA.
• What are the key differences between prokaryotic and eukaryotic mRNA processing and how do these differences affect gene expression?
  • In prokaryotic cells, mRNA is often immediately translated as it is transcribed since there is no nucleus to separate transcription from translation. Eukaryotic cells, however, undergo extensive mRNA processing that includes capping, polyadenylation, and splicing before translation can occur. These processes allow for regulation of gene expression and contribute to mRNA stability, impacting how efficiently genes are expressed in eukaryotes.
• Evaluate the implications of mRNA technology in medicine, especially regarding vaccine development and potential treatments for diseases.
  • mRNA technology has transformed modern medicine, particularly in vaccine development. Vaccines using mRNA teach cells to produce a harmless piece of a virus (like the spike protein of SARS-CoV-2), prompting an immune response without using live virus. This innovative approach not only speeds up vaccine production but also has potential applications in treating diseases by instructing cells to produce therapeutic proteins or even targeting specific mutations in cancer cells. As research continues, mRNA technology could lead to more personalized medicine and advanced treatments for various conditions.

Related terms

Transcription: The process by which the information in a segment of DNA is copied into mRNA by RNA polymerase.

Ribosome: A molecular machine found within all living cells that facilitates the translation of mRNA into protein.

tRNA: Transfer RNA, which brings amino acids to the ribosome during protein synthesis, matching them to the corresponding codons in the mRNA.