Messenger RNA

Definition

Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosomes, where proteins are synthesized. It acts as a template for translating the genetic code into amino acids, ultimately forming proteins that perform various functions in the cell. mRNA is crucial in the process of gene expression, ensuring that the information stored in DNA is accurately translated into functional proteins.

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. After synthesis, mRNA undergoes processing, including splicing, capping, and polyadenylation, to become mature mRNA ready for translation.
3. In eukaryotic cells, mRNA is transported from the nucleus to the cytoplasm, where ribosomes translate it into proteins.
4. Each mRNA molecule contains codons, which are sequences of three nucleotides that specify particular amino acids during protein synthesis.
5. The lifespan of mRNA varies; some mRNA molecules are quickly degraded after translation, while others can persist for longer periods to produce multiple protein copies.

Review Questions

• How does messenger RNA contribute to the process of protein synthesis at the ribosome?
  • Messenger RNA plays a key role in protein synthesis by acting as a template for ribosomes. Once the mRNA is transcribed from DNA and processed, it travels to the ribosome in the cytoplasm. The ribosome reads the sequence of codons on the mRNA and translates this information into a specific sequence of amino acids, leading to protein formation.
• Compare and contrast transcription and translation in terms of their roles in gene expression and how they relate to messenger RNA.
  • Transcription and translation are two crucial steps in gene expression. Transcription involves creating an mRNA copy from DNA in the nucleus, while translation occurs in the cytoplasm where ribosomes use the mRNA template to synthesize proteins. Both processes are interdependent; without transcription, there would be no mRNA available for translation, and thus no proteins could be produced.
• Evaluate the impact of mutations in messenger RNA on protein synthesis and potential cellular consequences.
  • Mutations in messenger RNA can significantly affect protein synthesis by altering codon sequences. This can lead to changes in amino acid composition, resulting in dysfunctional proteins that may lose their normal function or gain harmful properties. Such mutations could contribute to various diseases, including genetic disorders and cancers, highlighting the importance of accurate mRNA synthesis and translation.

Related terms

Ribosome: A cellular structure that synthesizes proteins by translating the mRNA sequence into a polypeptide chain, consisting of ribosomal RNA (rRNA) and proteins.

Translation:

The process in which the ribosome reads the sequence of mRNA and assembles amino acids into a polypeptide chain, forming a protein.

Transcription: The process of copying a segment of DNA into mRNA, allowing the genetic code to be transferred from DNA to mRNA.