Harvard Online
6 HN recommenders · recommended in 5 months, 2020–2024
7:45 · 3.7M views · Oct 9, 2017
A short Harvard Online animated lesson on how the mitochondrial electron transport chain works. It shows proton pumping and the machinery that drives ATP synthesis.
HN commenters share it to show how cells work as nanoscale machines, which many find mind-blowing.
6 comments from Hacker News
'Molecular machines' is not an overstatement. Here's an example of some of them working in harmony to maintain an essential electrochemical gradient across the lipid bilayer that encapsulates the mitochondria: this video It's a 7 minute video, if you only have a little time, skip around, but make sure you listen to the part starting at 6:17. DNA isn't just the blueprint for the machine or the blueprint for the factory that makes the machine, it's the blueprint for the entire supply chain required to build and operate an entire chemical industry of mind-bending complexity. Like doubling grains of rice on each square of a checkerboard, if you wanted to create a complete catalog of all possible combinations of a string of DNA that's 150 base pairs long, you would have to marshal all of the estimated matter in the observable universe and you'd still end up short. Most of the genes that create these proteins are tens of thousands of base pairs in length and the entire human genome is ~3 billion.
It's a very complex topic (especially if you aren't a chemist). I can't find an accessible video on the topic, but you want to look up photosystem II repair. You need to search up D1 replacement in photosystem II. To get a flavour of the nanomachine aspect of it all, check out this video on electron transport across membranes ( this video ). Electron transport in proteins is crazy complex and actually amounts to molecular circuits where energy is guided to different spots inside proteins complexes in a unidirectional fashion. This guy is the grand daddy of the field ( [LINK] ).
The thing that drove this home for me were the biovisions animations which got me to go back and basically learn high school biology. Seeing the mechanical nature of gene transciption and chemical signaling blew my mind. [LINK] this video On the other hand, I don't buy his thing about wishing his high school teacher had presented it differently. No on else can make you interested in this stuff. The best they can do is provide resources like the ones above.
Here is an animation of the Mitochondria in action. The mitochondria has two cell membranes. The gap in between is called the intermembrane space. It is also positively charged with protons. There are complexes 1-4 which continuously pump protons into this space. The ATP synthase molecule harnesses these protons, similar to a water wheel harnessing the flow of water, to make ATP which is the energy molecule the cell uses. this video
my favorite is this video once you look at microbiology you cannot unsee that it looks just like a massive, complicated stochasticaly-driven computer