http://www.mun.ca/biology/scarr/iGen3_05-03.html

http://www.nature.com/scitable/topicpage/operons-and-prokaryotic-gene-regulation-992

http://www.nature.com/scitable/topicpage/genome-packaging-in-prokaryotes-the-circular-chromosome-9113

In eukaryotes (organisms with a nuclear membrane), DNA undergoes replication and transcription in the nucleus, and proteins are made in the cytoplasm. RNA must therefore travel across the nuclear membrane before it undergoes translation. This means that transcription and translation are physically separated. The primary transcript, heterogeneous nuclear RNA (hnRNA), undergoes extensive post-transcriptional processing to make a messenger RNA (mRNA)molecule that can pass through the nuclear membrane.

http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a2.htmltranscription

http://www.youtube.com/watch?v=MkUgkDLp2iETranscription factors

http://www.youtube.com/watch?v=DoSRu15VtdMCap and tail