Protein synthesis is the process of creating protein molecules. DNA replication is the synthesis of a new DNA molecule from an existing DNA molecule. There are several similarities between protein synthesis and DNA replication: 

• Both processes occur inside the cell
• Double-stranded DNA molecules are involved in both processes
• An unwound DNA molecule acts as the initial template in both processes
• Both processes are essential for organisms to grow, develop, and function 
• Incorporation of wrong precursor molecules can cause errors to develop in both processes