Of course! To do this, you will need to open Advanced Options on the question.
You can then edit the Point Value of the question. For example, if you have a total of three questions, two with a weight of 1 and one with a weight of 2, the 2-point question is worth as much as the other two combined. A user who gets both 1-point questions correct but answers the 2-point question incorrectly will receive a grade of 50%.