Protein synthesis - Transcription, Translation & Function

Protein synthesis is a vital biological process where cells produce proteins, which are essential for nearly all cellular functions.
This process is directed by genetic information in DNA and occurs in two main stages: transcription and translation.

Transcription of Protein synthesis:

Protein synthesis enzyme RNA polymerase binds to the DNA at a specific site called the promoter, initiating the unwinding of the DNA helix.
RNA polymerase synthesizes a complementary mRNA strand using the DNA template (adenine pairs with uracil, and cytosine pairs with guanine).
The newly formed mRNA undergoes processing, including the addition of a 5′ cap and a 3′ poly-A tail.
The processed mRNA is then transported to the cytoplasm for the next stage.

Ribosomes read the mRNA sequence in sets of three nucleotides (codons), each specifying an amino acid.
Transfer RNA (tRNA), with its attached amino acid, recognizes specific codons via its anticodon and pairs with the mRNA.
The ribosome catalyzes the formation of peptide bonds, linking amino acids into a polypeptide chain.
Translation continues until a stop codon is reached, signaling the completion of the polypeptide.
The polypeptide then undergoes folding and modifications to become a fully functional protein.

Proteins play crucial roles in:
- Structural support (e.g., in cells and tissues).
- Acting as enzymes to speed up biochemical reactions.
- Transporting molecules across cell membranes.
- Involvement in cell signaling and immune defense.
The function of a protein is determined by its 3D structure, which is dictated by its amino acid sequence, directly linking genes to protein function.