1. Transcription:
* DNA unwinds: The DNA double helix unwinds and separates in the nucleus.
* RNA polymerase binds: An enzyme called RNA polymerase binds to a specific region on the DNA called the promoter.
* mRNA synthesis: RNA polymerase uses one strand of the DNA as a template to synthesize a complementary strand of messenger RNA (mRNA). This mRNA molecule carries the genetic code from the nucleus to the cytoplasm.
* mRNA processing: The newly synthesized mRNA undergoes processing, including capping, splicing, and polyadenylation, to become a functional molecule.
2. Translation:
* mRNA exits the nucleus: The processed mRNA molecule moves from the nucleus into the cytoplasm through nuclear pores.
* mRNA binds to ribosomes: In the cytoplasm, the mRNA molecule binds to ribosomes, which are the protein synthesis machinery.
* tRNA brings amino acids: Transfer RNA (tRNA) molecules, each carrying a specific amino acid, bind to the mRNA according to the genetic code.
* Polypeptide formation: The ribosome moves along the mRNA, bringing the amino acids into the correct order, forming a polypeptide chain.
* Protein folding: The polypeptide chain folds into a specific three-dimensional structure, forming a functional protein.
In summary:
The genetic code is first transcribed from DNA into mRNA in the nucleus. The mRNA then travels to the cytoplasm and binds to ribosomes, where it is translated into a protein. This process is essential for gene expression and the production of all the proteins required for cellular function.
