MRNA

Definition

mRNA, or messenger RNA, is a single-stranded molecule that carries genetic information from DNA to the ribosome, where proteins are synthesized. It serves as a template for translating the sequence of nucleotides into a specific amino acid sequence, ultimately determining the structure and function of proteins within cells.

5 Must Know Facts For Your Next Test

1. mRNA is synthesized in the nucleus during transcription, where RNA polymerase reads the DNA template and creates a complementary mRNA strand.
2. After synthesis, mRNA undergoes processing which includes capping, polyadenylation, and splicing before it exits the nucleus.
3. Each mRNA molecule contains codons, which are sequences of three nucleotides that correspond to specific amino acids or stop signals during protein synthesis.
4. mRNA has a relatively short lifespan in the cell, often degraded after translation to regulate protein production and maintain cellular function.
5. The ribosome reads mRNA in a 5' to 3' direction, ensuring that proteins are assembled in the correct order according to the genetic code.

Review Questions

• How does mRNA function as a bridge between DNA and protein synthesis?
  • mRNA acts as a crucial intermediary that transfers genetic information from DNA in the nucleus to the ribosomes in the cytoplasm. During transcription, DNA is used as a template to synthesize mRNA. This mRNA then carries the specific sequence of codons that dictate the order of amino acids during translation, effectively linking genetic instructions with protein formation.
• Discuss the role of mRNA processing and its significance in gene expression regulation.
  • mRNA processing involves several critical steps such as capping, polyadenylation, and splicing. These modifications enhance the stability of mRNA and facilitate its export from the nucleus to the cytoplasm. By regulating how mRNA is processed, cells can control which proteins are produced and when, making this a key aspect of gene expression regulation.
• Evaluate the impact of mutations in mRNA on protein synthesis and potential cellular outcomes.
  • Mutations in mRNA can lead to changes in the amino acid sequence of proteins, potentially altering their function or stability. For instance, if a mutation causes a premature stop codon to appear in an mRNA sequence, it can result in truncated proteins that may be nonfunctional. Such changes can disrupt cellular processes and lead to diseases, emphasizing the importance of accurate mRNA translation in maintaining cellular health.

Related terms

Transcription: The process by which genetic information encoded in DNA is copied into mRNA, allowing for the synthesis of proteins.

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

tRNA: Transfer RNA is responsible for bringing the correct amino acids to the ribosome during protein synthesis, based on the sequence specified by the mRNA.