Final answer:
The final three-dimensional shape of a protein is determined by the gene encoding the protein, as the amino acid sequence it dictates is crucial for the protein to fold into its functional shape. Posttranslational modifications also play an important role after protein synthesis. The protein's shape is essential to its specific biological function.
Step-by-step explanation:
The final three-dimensional shape of a protein is determined by the gene encoding that protein. This is because the gene provides the instructions for the sequence of amino acids in the protein, which is known as the primary structure. The sequence of amino acids is fundamental to determining the protein's shape through a series of folding stages, including secondary, tertiary, and sometimes quaternary structures. Interactions like hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges between amino acid residues that can be far apart in the chain all contribute to the final structure. Posttranslational modifications can occur after protein synthesis and are essential for the complete functioning of a protein. These modifications, along with the linear sequence dictated by the gene, are crucial for the protein to take on its functional three-dimensional shape.
Indeed, the shape of proteins is central to their function, similar to how certain utensils are designed for specific uses in eating. If a protein loses its specific three-dimensional shape, it may not be able to perform its intended function. This emphasizes the importance of the precise amino acid sequence and the complex folding that occurs as a result.