Which component of the cell is primarily involved in protein synthesis?

The component of the cell that is primarily involved in protein synthesis is ribosomes. Ribosomes are molecular machines found within all living cells. They serve the crucial function of translating messenger RNA (mRNA) into polypeptide chains, which subsequently fold into functional proteins. This process is known as translation, and it takes place in both the cytoplasm and on the rough endoplasmic reticulum. The ribosome facilitates the binding of transfer RNA (tRNA), which carries specific amino acids, to the corresponding codons on the mRNA strand, thus assembling the amino acids into a polypeptide chain according to the genetic code.

While the nucleus plays an essential role in the synthesis of mRNA by transcription, it is the ribosome that executes the protein synthesis itself. The mitochondria are mainly involved in energy production through cellular respiration, and the Golgi apparatus is responsible for modifying, sorting, and packaging proteins for secretion or delivery to other organelles. Therefore, the ribosomes are the key players in the protein synthesis process, making them the correct choice for this question.