Briefly describe the process of building the protein polymer. Which macromolecular component of the enzyme catalyzes the chemical reaction that forms that bond?
The correct answer and explanation is:
The process of building a protein polymer, or polypeptide chain, is known as protein synthesis. It occurs in two main stages: transcription and translation.
- Transcription: This process occurs in the nucleus, where the DNA sequence of a gene is copied into messenger RNA (mRNA). The mRNA serves as a template for the next stage of protein synthesis.
- Translation: The mRNA travels from the nucleus to the cytoplasm, where ribosomes read the mRNA code and use it to assemble a specific sequence of amino acids, creating the protein polymer. Transfer RNA (tRNA) molecules bring amino acids to the ribosome, where the ribosome forms peptide bonds between the amino acids.
The bond that forms between amino acids is a peptide bond, and this bond is created through a dehydration synthesis reaction. In this reaction, the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water and forming a peptide bond.
The macromolecular component that catalyzes this chemical reaction is the ribosome. The ribosome is made up of ribosomal RNA (rRNA) and proteins. The rRNA within the ribosome has catalytic properties, and it is responsible for the formation of peptide bonds between amino acids during translation. This process is known as peptidyl transferase activity, where the ribosome facilitates the formation of the peptide bond by aligning the amino acids in the correct orientation and catalyzing the removal of water to form the bond.
Thus, the key to protein polymerization is the ribosome and its rRNA, which act as the enzyme responsible for catalyzing the bond formation in the peptide chain.