Transcription and translation are two important processes involved in protein synthesis.
Transcription:
- Transcription is the process by which DNA is used as a template to synthesize RNA.
- The first step in transcription is the binding of RNA polymerase to a specific region of DNA called the promoter.
- RNA polymerase unwinds the DNA double helix and adds complementary RNA nucleotides to the growing RNA strand.
- Transcription continues until RNA polymerase reaches the end of the DNA template or encounters a termination sequence.
- The resulting RNA molecule, called messenger RNA (mRNA), carries the genetic information from DNA to the ribosome, where it will be used to synthesize a protein.
Translation:
- Translation is the process by which mRNA is used as a template to synthesize a protein.
- The process begins when the ribosome binds to the mRNA and the first tRNA molecule carrying the amino acid methionine binds to the start codon (AUG).
- The ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain as it reads each codon (three nucleotides).
- Each tRNA molecule carries a specific amino acid that matches the codon on the mRNA.
- The process continues until the ribosome encounters a stop codon (UAA, UAG, or UGA), at which point the polypeptide chain is released and the ribosome dissociates from the mRNA.
Overall, transcription and translation are key processes in protein synthesis. Transcription converts the genetic information stored in DNA into RNA, which is then used to direct the synthesis of a protein during translation. These processes are tightly regulated and involve a complex interplay of enzymes, RNA molecules, and ribosomes.