Life is chemistry

Is life a complex bunch of chemical reactions or is there something more? Studying wine production led scientists to some interesting discussions.

Transcript

Sir Paul Nurse: Life is chemistry. This is the idea that you can understand living processes in terms of their chemistry, and for that matter their physics. This is not an idea that we are particularly astonished at today, but of course 150 years ago Vitalism was thought by many to apply to living things. That is, there was something about living cells, living organisms, that was vital or different compared with the normal laws of physics and chemistry.

Well, the notion that chemistry is important for life has its origins with the chemist, Lavoisier. Lavoisier was French, one of the great chemists of all time - he discovered how oxygen works, for example. And being French he was also interested in wine. And he thought about the fermentation process that generated wine and came to the conclusion that the fermentation process that was going on in wine formation had something to do with chemical reactions that were occurring in this process. He lost his head in the French Revolution to the guillotine, so his particular studies stopped at around 1794.

But they were taken up by Louis Pasteur. And in the 1850’s Pasteur was approached by wine growers in France who were concerned about the quality of their wine. Sometimes you would get good alcohol production and sometimes you would get bad fermentation and you would get an acid taste, usually due to acetic acid, to vinegar-like substances. And to investigate this he turned to the microscope in the 1850s to look at the fermentation going on in these two situations. And every time there was a good fermentation, producing decent wine, he saw under the microscope yeast. And every time he saw a bad fermentation, he looked under the microscope and he saw bacteria. So he came to the conclusion that these different chemicals, alcohol or acetic acid, were being generated by different microbes. And it was specific fermentations, which were producing specific chemicals, were being caused by specific microbes.

And he concluded that the generation of these different chemicals was probably a physiological act of the living cell to yield chemical products important for the life of that cell. This is the first clear statement that chemistry was important for the life of a living organism, for these microbes that he was studying. The next step in this was to actually isolate from these microbes what we now know to be enzymes, which could carry out these chemical reactions.