Don't make an essay out of your answer. Talk about your schooling as it relates to the position. Tell them things you have done outside of your classes that are related to the position.

Maybe even a part time job that is somehow related plus things you have written about that are related. Also briefly talk about your personal interest in this position and how you feel passionate about your career and future line of work. As a general rule, you should not discuss your personal life, hobbies, family, etc. Because that's not what they are looking for.