the genetic code is nearly universal, which means that a specific codon (such as UUU) codes for the same amino acid (such as Phenylalanine) in almost all organisms, from bacteria to humans . This fundamental property allows the cellular machinery of a bacterium to correctly translate human genetic sequences into the intended protein . A prime example of this is the large-scale production of human insulin in E. coli bacteria . It is important to note that bacterial cells cannot carry out RNA splicing (the removal of introns), so for genetic engineering to work, scientists must use DNA sequences where introns are already absent . Understanding these core molecular principles is a high-priority strategy for medical aspirants, as NCERT textbooks serve as the definitive source for approximately 95% of NEET Biology questions .