How to apply for internships with poor academic transcript?

I am starting to apply for summer internships, some of which ask for an academic transcript. Unfortunately, during my sophomore year, I was on academic probation for the first semester and just missed it second semester. I want to explain the poor academic performance somewhere in my application packet, but do not know where to do so. Some websites say to include it in the additional statement, but this particular application does not ask for one. What should I do?How to apply for internships with poor academic transcript?
You should be including a cover letter and resume with your applications most likely. In your cover letter I would mention it. Also, don't make many excuses, unless there is a good one. Instead, try and focus on important extracurriculars you were involved in, projects that you worked on, and examples of leadership. To many potential employers, examples of good communication and leadership is much more important than knowing that you can study for a test.