Where does protein production occur in relation to DNA?

Protein production occurs primarily in the cytosol, where ribosomes synthesize proteins based on the instructions provided by messenger RNA (mRNA), which is transcribed from DNA. Once the DNA in the nucleus is transcribed into mRNA, this mRNA is then transported out of the nucleus into the cytosol. Here, ribosomes read the sequence of the mRNA and translate it into a polypeptide chain that eventually folds into a functional protein.

While some cellular components involved in protein synthesis, such as ribosomes, can also be found bound to the endoplasmic reticulum, the ribosomes that float freely in the cytosol are responsible for producing many types of proteins, particularly those that function within the cell itself.

Other options refer to different organelles or structural components of the cell. The mitochondria are involved in energy production and have their own unique set of proteins, but they are not the primary site for general protein synthesis. The nucleus houses the DNA and is the site of transcription, but it does not directly produce proteins. The plasma membrane plays a role in signaling and transport but is not involved in the synthesis of proteins themselves.