Messenger RNA

Definition

Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosome, where proteins are synthesized. It acts as a template for translation, guiding the assembly of amino acids into proteins based on the sequence of nucleotides. This process is essential for gene expression and the functioning of cells.

5 Must Know Facts For Your Next Test

1. mRNA is synthesized during transcription, where a specific segment of DNA is copied into RNA by RNA polymerase.
2. mRNA undergoes processing before translation, which includes capping, polyadenylation, and splicing to remove introns and join exons.
3. Each mRNA molecule has a specific sequence of codons that correspond to particular amino acids in the protein being produced.
4. In eukaryotic cells, mRNA is transported from the nucleus to the cytoplasm where translation occurs.
5. The lifespan of mRNA can vary greatly, influencing how long a gene is expressed; some mRNAs are quickly degraded while others persist for longer periods.

Review Questions

• How does messenger RNA contribute to the process of protein synthesis?
  • Messenger RNA plays a critical role in protein synthesis by serving as the template that carries genetic instructions from DNA to ribosomes. During translation, ribosomes read the sequence of codons in the mRNA, which specifies the order of amino acids to be linked together to form a protein. This ensures that proteins are made accurately according to the genetic code.
• What are the key steps involved in the processing of messenger RNA before it can be translated?
  • Before mRNA can be translated into protein, it undergoes several key processing steps. First, a 5' cap is added to protect the mRNA and assist in ribosome binding. Next, a poly-A tail is added to the 3' end for stability and export from the nucleus. Finally, introns are removed through splicing, allowing exons to be joined together. This processed mRNA is then ready for translation in the cytoplasm.
• Evaluate the implications of mRNA degradation on gene expression regulation in eukaryotic cells.
  • The degradation of messenger RNA has significant implications for regulating gene expression in eukaryotic cells. The lifespan of mRNA molecules can vary widely; those that are rapidly degraded lead to transient protein production, while longer-lived mRNAs can result in sustained expression levels. This dynamic control allows cells to respond quickly to changes in their environment or developmental cues by modulating protein synthesis according to current needs.

Related terms

DNA: Deoxyribonucleic acid, the molecule that carries the genetic instructions used in growth, development, functioning, and reproduction of all living organisms.

Ribosome: A cellular structure that serves as the site of protein synthesis, where mRNA is translated into polypeptide chains.

Translation: The process by which ribosomes synthesize proteins using the information encoded in mRNA.