Can your employer make you do something not in your job description?

Short answer is yes. You are en employee of the company and they are paying you for your time. Besides, most actual job descriptions also say something to the effect of "and all other things as assigned by management".

It is a poor employee that has to go to the job description defense. Look at it as the company making sure you have something to do and keeping you employed. I am sure that there are thousands of people that would love to be in the position of having a job and not worried about being asked to do something out of the ordinary.

Add together the hours of all of the people in position doing something that is out of the ordinary in your department. Does it add up to more than one person per week? Many managers will take on additional roles for people in their department in an attempt to save jobs. I am not saying this is the case, but it is typical for people to jump to the "its not my job" defense - when it may be your job that is lost if it does not get done.