DNA Interactive (http://www.dnai.org/), in conjunction with DNA Learning Center, is an amazing resource with interactive activities for students: Timeline of discoveries in genes and molecular biology, how DNA and its structure provide the basis for genes and gene expression. The animations on DNA replication, transcription, and translation are SUPERB. I started using these when they came out on DVD. I’m so glad they have these animations available on YouTube now as well. Here’s the one on DNA Transcription.
Teachers can register for a free account with access to resources: teacher’s guide, student worksheets, answer sheets.
One warning: the site does not work on the iPads since it requires Flash to work.