If you want to find some random biological stat, the BioNumbers database is your friend. It’s where I go when I want to know how many hairs are on a head, how wide those hairs are, or, more commonly things like how fast a ribosome translates mRNA into protein. The database will give you the numbers as well as information about where that number comes from – it gives credit where credit is due and links you to the paper where scientists reported it. Not only is this good ethically, but it’s also good so you can cite it yourself, etc. and check out the experimental details that you might want to take into account when interpreting the numbers. These details can be really important as growth conditions, etc. can greatly influence various concentrations, rates, sizes, and more. Thankfully too, BioNumbers actually includes some of the experimental details in the number’s entry.
BioNumbers: The Database of Useful Biological Numbers – it looks for published data on your query https://bionumbers.hms.harvard.edu/search.aspx
YouTube to today’s video in case embed isn’t working: https://youtu.be/-ZDTUL-seAU
There’s also an accompanying book, Cell Biology by the Numbers (FREE online). In grad school I got to take an intensive week-long course on Physical Biology of the Cell that I still think about a lot. It was taught by one of the book’s authors, Caltech’s Rob Phillips – the other is Ron Milo. The book does a great job giving an intuitive sense of what concentrations really “look like” and it’s so helpful! For example, 1 nanomolar (1nM) corresponds to about 1 molecule per e. coli cell. So micro molar (1μM) would be about 1000 molecules per e. coli cell. mM about 1 million per e. coli cell, etc. An average-ish human cell is about 2000 times as big as that bacterial cell so you’d need 2000 times as many molecules to get the same concentration.
The book goes into how you can make similar back-of-the-envelope estimates of various molecular sizes and rates. It does a great job helping you always keep things in perspective. There’s a printed version you can buy or you can download a free PDF of it or read it interactively on its website: http://book.bionumbers.org/
In it, you’ll also find some helpful data tables, many of which have a column titled “BNID”. That’s the BioNumbers ID pointing you to where you can find the corresponding entry in the BioNumbers databank which will direct you to the research paper that determined the value in the table.
You can also just search BioNumbers directly for any sort of bio stat you’re looking for. So helpful!
Also helpful is that Ron Milo has a whole course on YouTube as well: https://youtube.com/playlist?list=PLnW9-ausEh9GDI5e728mPN1LXnO0deocP
When we work in test tubes a lot, it can be easy to forget that molecules typically do not! So I highly recommend everyone take some time to check out these resources and start developing a more realistic sense of what is realistic! Because concentrations matter a lot in biochemistry. As do rates. So give them the respect they deserve (it will also help you see which direction a reaction is likely to proceed, whether your concentrations are too high or low to be meaningful, whether you could realistically expect two molecules to be able to find and bind one another in a cell, etc.)
Speaking of resources, I have some content on unit conversions, etc. here: blog: https://bit.ly/metric_calcs ; YouTube: https://youtu.be/A-J7kdLNb8c
And small lengths here: blog: https://bit.ly/talkingsmall ; YouTube: https://youtu.be/-byu5MvrTCo
And molarity here: http://bit.ly/solutionconcentrations
