Yes, into the question in which you want the video to appear - in the "Question text" box? Such as the description question you mentioned, as long as you know the question will appear on the quiz.
If you however want to re-use the same video in several questions you might keep a single copy in one question and point to it via alias from another. I haven't tested that though. I think re-using one description question with multiple quizzes might be the smartest move here.
Whatever you do, make sure you test the final result from a real student's account to make sure a student has access. And do try with the other formats for the video tag and ask your students if they can view this as conveniently as usual. Maybe you have some silly clips you can use to test everything out.
Wish you best of luck with this