In a mammalian cell, the protein is synthesized by

Ribosomes are the primary sites of protein synthesis in all living cells, including mammalian cells. They are often referred to as the "protein factories" of the cell because they facilitate the translation of genetic information from messenger RNA (mRNA) into polypeptide chains.

• Ribosomes: These can be found floating freely in the cytoplasm or attached to the Rough Endoplasmic Reticulum (RER).
• Golgi Apparatus: This organelle is involved in the modification, sorting, and packaging of proteins after they have been synthesized.
• Lysosomes: These are membrane-bound organelles containing digestive enzymes used to break down waste materials and cellular debris.
• Smooth Endoplasmic Reticulum (SER): This is primarily responsible for the synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs, rather than protein synthesis.