Excellent clips of how some parts of the cell operate. Link
[ame="http://www.youtube.com/watch?v=UB6G9GD2KFk"]Leukocyte[/ame]
[ame="http://www.youtube.com/watch?v=E8NHcQesYl8"]DNA wrapping and replication[/ame]
Nice video showing the mechanism of cell death via apoptosis through tumour necrosis factor (TNF) signaling in a caspase-dependent way. An incredibly complex and controlled process. Apoptosis