1. Transcription: The DNA sequence of a gene is transcribed into a messenger RNA (mRNA) molecule. This mRNA molecule carries the genetic code from the DNA to the ribosomes, where protein synthesis occurs.
2. Translation: The mRNA molecule is translated into a polypeptide chain. This process occurs at the ribosomes, which read the mRNA sequence in codons (groups of three nucleotides). Each codon specifies a particular amino acid.
3. Amino Acid Chain Formation: As the ribosome reads the mRNA, it adds the corresponding amino acids to the growing polypeptide chain. This chain is then folded into a specific three-dimensional structure, which determines its function.
In summary:
* DNA contains the genetic code that specifies the amino acid sequence of a polypeptide.
* mRNA acts as a messenger, carrying the code from the DNA to the ribosomes.
* Ribosomes read the mRNA code and assemble the polypeptide chain using the appropriate amino acids.
Therefore, the DNA sequence is the ultimate programmer of the amino acid sequence of a polypeptide.
