I’ve always been amazed and fascinated that in a cell, which is basically a sack of biochemicals in which a gazillion things are happening simultaneously, the actions shown below happen so fast. One of the more striking things is the speed at which DNA replicates and is transcribed into messenger RNA which is then translated into proteins. The videos below show how this happens, but remember that it happens in a milieu in which a lot of other things are happening at the same time, like metabolism and intake of chemicals into cells.
These two videos come from The Walter and Eliza Hall Institute for Medical Research in Australia.
These DNA molecular visualizations were created for the multifaceted ‘DNA’ project, celebrating the 50th anniversary in 2003 of the discovery of the double helix. The ‘DNA’ project includes a five-part documentary series, museum film and ‘DNAi’ online resources for teachers and students.
The dynamics and molecular shapes were based on X-ray crystallographic models and other published scientific data sets. Leading scientists, including many Nobel Laureates, critiqued the animations during their development. Particular effort was made to ensure the relative shapes, sizes and ‘real-time’ dynamics were as accurate as possible.
The second part of this first video, which shows DNA replication—the splitting of a single DNA molecule into two strands, on each of which is built a complementary strand—is particularly fascinating, as it shows the complexity that has resulted from evolution. (This includes the way that one of the strands is copied backwards, since synthesis goes in only one direction.)
The second video partly duplicates some of the first, but is more comprehensive. Particularly fascinating is the real-time speed with which transcription occurs (the synthesis of a messenger RNA strand from a DNA strand; see start at about 3:25). I wish they had a full video of the translation of messenger RNA into proteins, but I can’t seem to find one produced by this organization.
To a biologist like me, watching these videos is a spiritual experience. And by that I don’t mean it invokes visions of a divine creator, but awe before the power of natural selection.
One note: the second video says that each of our ten trillion cells contains 1.8 meters of DNA. If you multiply that out, it comes to 18 billion kilometers of DNA in each human—enough to stretch from the Earth to the Moon 50,000 times. (This is assuming I did my math right). And that is in each person!
Here’s a TEDx Sydney talk by Drew Berry, a prizewinning “biomedical animator” who is the person responsible for these videos, explaining what he does and what the videos show. (There’s some duplication with the animations above as he explains what’s happening.) The animation of how chromosome splitting during cell division (“mitosis”) takes place is fantastic.