Strangely enough, English exams have nothing to do with memorising an essay and more to do with how you can structure your words. They want you to demonstrate everything you have learned about words & sentences over the past however many years, but they need something to "talk about" to get you to do this. They try to make it fruitful and arty, but in typical teacher fashion, fail miserably.
It isn't about how well you understand the topic of power (pre 2003), journeys (2004-2009?) or 'belonging' (2010+), but how well you articulate yourself. The content of the essay is somewhat irrelevant. It's a bit deceitful in this way, because all of your other subject exams are memory tests - how well you remember dot points or formulas. English is a bit more (or less, whatever way you look at it). It's not about how well you can remember a particular text, but how well you articulate what you remember about it and respond to the question.