How does the cell convert DNA into working proteins?

The cell converts DNA into working proteins through the processes of transcription and translation. Transcription occurs in the nucleus of the cell and involves the synthesis of an mRNA molecule complementary to a specific region of DNA. During transcription, the enzyme RNA polymerase binds to a promoter region on the DNA and unwinds the double helix. It then reads the DNA sequence and synthesizes a complementary RNA strand using nucleotide bases (adenine, cytosine, guanine, and uracil) according to the base-pairing rules (A-U, C-G). This newly synthesized mRNA molecule is transported into the cytoplasm in order to be translated into a protein molecule.

Translation occurs in the cell's cytoplasm, where the mRNA interacts with ribosomes. These ribosomes interpret the sequence of nucleotides on the mRNA, with each set of three nucleotides (known as a codon) typically corresponding to a specific amino acid. Transfer RNA (tRNA) molecules carry individual amino acids to the ribosome, where they are assembled into a protein chain. This process continues until the ribosome reaches a "stop" codon, signaling the end of protein synthesis.