<p>The usual Berkeley chemistry sequence for biology majors and pre-meds is:</p>
<p>1A+, 3A<em>, 3B</em>, upper division MCB biochemistry course (with associated labs)</p>
<p>The usual Berkeley chemistry sequence for chemistry and chemical engineering majors is:</p>
<p>4A+, 4B+, 112A<em>, 112B</em> (with associated labs; chemical engineering majors do not need 112B)</p>
<p>The extension courses appear to be for a post-bacc pre-med program, and follow a fairly typical sequence:</p>
<p>X19A+, X19B+, X36A<em>, X36B</em> (with associated labs)</p>
<ul>
<li>= general chemistry courses</li>
<li>= organic chemistry courses</li>
</ul>
<p>The extension courses above may be usable if you want to do pre-med, but do not need chemistry for your major (but then you want to check with medical schools). If you need chemistry for your major, take CC courses that articulate to the needed courses. Taking CC courses avoids the issue of having units from a 4-year school when you need to stay under a unit limit for transfer admission purposes.</p>
<p>The extension courses listed as “introduction”, X16 and X18, are probably for non-majors.</p>