<p>You can’t declare Biochem as your major until you are a junior. How difficult it is to do that depends on how well you do in the preparatory courses (the bio core, chem, ochem, ect). They take 24 people a year so I’ll assume it’s competitive. The requirements are detailed here:</p>
<p>[UCI</a> Change of Major Criteria: School of Biological Sciences](<a href=“http://www.changeofmajor.uci.edu/CoM_BioSci.html#biochem]UCI”>http://www.changeofmajor.uci.edu/CoM_BioSci.html#biochem)</p>