You will have to prepare just BJT not MOSFET. BJT are important and every year one question covers the spectrum of BJT such as manufacturing of PNP transistors and NPN transistors, Operation of BJT as Common base, Common Emitter and Common Collector, Zener Diode, Transistor as Constant voltage source etc. So you must have to prepare the BJT section. This year in 2014 also, the BJT has one question. most of the candidates sitting nearby my chair attempted this question.