Protein synthesis in cells occurs through two primary processes: transcription and translation.

This fundamental biological process enables cells to construct proteins, essential for various cellular functions. The process is divided into two main stages: transcription and translation, both of which are governed by the cell’s genetic material, DNA and RNA.

In the first stage, known as transcription, the information encoded in DNA is transcribed into a molecule called messenger RNA (mRNA). This process takes place in the cell’s nucleus. During transcription, the DNA strand unwinds, and one of its two strands serves as a template for synthesizing the mRNA. An enzyme called RNA polymerase facilitates this process. The resulting mRNA molecule is a complementary copy of the DNA strand, with one key difference: it substitutes the base thymine ($T$) with uracil ($U$). Once transcription is complete, the mRNA detaches from the DNA and exits the nucleus.

The second stage, translation, occurs in the cytoplasm, specifically on ribosomes. Here, the mRNA molecule binds to a ribosome, where its sequence is translated into a protein. This translation is carried out by transfer RNA (tRNA) molecules, each of which carries a specific amino acid. Each tRNA molecule contains an anticodon that pairs with a corresponding codon (a sequence of three bases) on the mRNA. As the ribosome progresses along the mRNA, it matches the tRNA anticodons with the mRNA codons, sequentially adding the appropriate amino acids to form a growing protein chain.

This translation process continues until a stop codon is encountered on the mRNA. At this juncture, the completed protein is released, marking the conclusion of protein synthesis. The newly synthesized protein can then perform its designated functions within the cell.

In summary, protein synthesis is a complex yet crucial process that enables cells to produce the proteins necessary for their functionality. It requires the precise coordination of DNA, RNA, and various enzymes working in concert within the cell.