Spontaneous uncoded chemical reactions in living systems?

[icakeov]

How easy (or not) is it for spontaneous chemical reactions to occur in a living cell, but particularly reactions that are not a result of and between coded molecules?

For example, when we eat food, in the process while the essential molecules are being taken to be integrated into "coded molecules", aren't they constantly looking to interact with other molecules around them? I am not including invading bacteria or viruses, I am mainly thinking monomers, functional groups, lipids, etc.

For example, could some polymers spontaneously form during that time? And then react with some other simple or complex molecules. Or is the organism's environment so "regulated" that something like this could rarely happen?

Any feedback appreciated!

 

[jim mcnamara]

I think you are asking - can a nutrient change into something else non-nutritive or become a major problem ? or maybe detrimental? yes to both.
The obvious followup is 'what causes this to happen'? Simple answer: environment.

One kind of simple example: way wrong amounts or too long a duration of larger than required amounts (sort of a slow overdose) of a molecule or nutrient.
Selenium, Vitamin D, Vitamin A (retinol) are all required nutrients by humans. In high quantity, i.e., relative to what is required, they all become toxic to humans.
One of the problems here is these molecules get changed into something not useful, because the body does not have the machinery to detoxify the normally transient intermediate storage form. Simply too much: Vitamin D is actually a hormone and can cause rapid buildups of calcium deposits in arteries. Not good.

Another example:
Electrolytes are in a delicate balance (Na, K, Ca, Mg) - when they go wonky for environmental reasons like heat exhaustion or dehydration, it can mean death.

You need to read about homeostasis:
https://en.wikipedia.org/wiki/Homeostasis

 

[icakeov]

Great, Jim, that is so helpful, and great examples. The only one I could think of was flatulence.. :)
Will explore it further now, thanks for the link!

 

[NC_Seattle]

All of the reactions that occur in the cell that are facilitated by coded molecules can also occur naturally in solution. Because the activation barrier (the energy level for the intermediate molecules) is typically high however these reactions occur at a very low rate. That's the whole purpose of enzymes is to greatly accelerate these naturally occurring reactions.

The word 'spontaneous' is typically used to refer to exothermic reactions, which is where the products are more stable than the reactants. The opposite of this is endothermic reactions, where the products are less stable than the reactants. They can also occur naturally in solution, even though they will likely be reversed afterwards. They also typically have high activation barriers just like spontaneous reactions and thus will also occur at a very low rate.

Molecules are also reacting randomly with many other molecules - at a very low rate. Your example of polymerization can occur as well although however there are mechanisms in place however to degrade and get rid of unwanted products. The best example of this would be enzymes that neutralize naturally produced free radicals.

Flatulence is caused by bacterial anaerobic fermentation of human-indigestible carbohydrates, which takes several different reactions working in sequence (a pathway). Again, it's possible for these reactions to occur naturally however there's so many bacteria in our gut and they work so quickly that the natural reactions are vanishingly few compared to the ones facilitated by microbes. The chance that one complex carbohydrate could go through all the necessary reactions naturally to produce methane is vanishingly tiny.

 

[icakeov]

That is so helpful! Thank you NC_Seattle!