DNA makes protein through a two-step process: transcription and translation.
Transcription: DNA to mRNA
First, DNA's genetic code is transcribed into messenger ribonucleic acid (mRNA). Enzymes, specifically RNA polymerase, read the DNA sequence and create a complementary mRNA molecule. This mRNA molecule carries the genetic information from the nucleus to the ribosomes in the cytoplasm. Essentially, it's like copying a recipe from a cookbook (DNA) onto a smaller card (mRNA) to take to the kitchen.
Translation: mRNA to Protein
Next, the mRNA molecule is translated into a sequence of amino acids, which are the building blocks of proteins. This process occurs at ribosomes. The ribosome reads the mRNA sequence in codons (three-nucleotide sequences), each of which specifies a particular amino acid. Transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome, matching their anticodon sequence to the mRNA codon. The ribosome then joins these amino acids together, forming a polypeptide chain. This polypeptide chain folds into a specific three-dimensional structure, creating a functional protein. It's like using the instructions on the card (mRNA) to gather the ingredients (amino acids) and build the dish (protein).
| Step | Location | Input | Output | Enzyme(s) Involved |
|---|---|---|---|---|
| Transcription | Nucleus | DNA | mRNA | RNA Polymerase |
| Translation | Ribosome (Cytoplasm) | mRNA, tRNA, Amino acids | Protein | Ribosomes, Aminoacyl-tRNA synthetases |
In summary, DNA provides the instructions, mRNA carries those instructions, and ribosomes use those instructions to assemble proteins from amino acids. This intricate process ensures that the genetic information stored in DNA is accurately translated into the diverse array of proteins necessary for life.
