<prompt> In drug metabolism, hepatic cytochrome P-450 system is responsible for:Phase I reactions hydrolysis, oxidation, reduction etc. onlyPhase II reactions conjugation, synthesis etc. onlyBoth phase I and II reactionsConverting hydrophilic metabolites to lipophilic metabolites  <response>: Ans. A Phase I reactions hydrolysis, oxidation, reduction etc. onlyRef: Katzung 13the p60; KDT 8the p32Cytochrome P450 enzymes are responsible for phase I reactions only whereas microsomal enzymes can be involved in phase II also glucuronide conjugation 