First of all, make sure that you indicate on the question itself the directionality of the sequence: which makes this (by convention) 5′ AGCTCAG 3′. We assume that any sequence written without the 5′ and 3′ designations is from the sense strand, and reads from 5′ on the left to 3′ on the right. Therefore, the complementary sequence, which is being asked for, must go from 3′ to 5′ as matched up (because it runs in the opposite direction). So, this is 3′ TCGAGTC 5′. It is true that we often write sequences without the formal directionality indicators, and if so, we do it from 5′ to 3′. However, if you put “CTGAGCT” as your answer, experience tells me that you have a very good chance of getting it marked wrong (unless your instructor is testing you all with a little tricky questioning).
Schemas are used to categorize information and draw conclusions, based on patterns and the relationships between them. In this case, you see your new roommate looking and behaving the way we believe an intellectual person would and you automatically assume that he/she is intellectual.
