What is the dependent clause in the sentence? If we are going to make it to the movie on time, we really need to leave right now.

The dependent clause of the sentence is "If we are going to make it to the movie on time," because it depends on the next part of the sentence to make sense. Without the next half of the sentence, the clause left alone wouldn't make any sense. The other clause is independent, meaning that it still makes sense when it stands without the dependent clause.