Why are enzymes required for so many biochemical reactions?

The question was closed as being “too broad,” but it specifically intended to be a big picture question. Any more specificity loses the thrust of the question. I’ve already received three answers (originally 4 but one was removed), all of which answer the question quite clearly - and each answer contributes in its own way towards a greater understanding. With all due respect, what could possibly be the point of choking off inquiry in an area of knowledge where curiosity is typically celebrated? Why not err on the side of “clearly there are people that understand the question, so why not let people decide for themselves if the question is to broad?” Thanks


2 Answers 2


In a way I am of a different opinion than orthocresol, I agree with the closure; here's my take.

Even after reading the question again and again, then reading all the answers, and reading the question again, I still cannot really figure out what you actually want to know; something I already pointed out in a comment. To me the question boils down to: why did enzymes evolve? That is my own personal opinion and take-away from it, and precisely for that reason I have left the comment. And in that context I agree that it is not focused enough.

Often such questions (in the context how I perceived it) might be closed as duplicates of Resources for learning Chemistry, as a standard textbook may do a better job in explaining the fundamental concepts. You are very welcome to ask questions to clarify these concepts.

Maybe I am too hung up on the wording. I just cannot understand what you mean with the following:

Given that the probability of three molecules coexisting and colliding is less than two, [...]

The probability of three molecules coexisting is close to one; all probabilities are at most one, so I don't understand what you mean with 'less than two'.

In an enzymatic reaction there is no collision between three molecules to begin with; I cannot think of any reaction, where three molecules collide to form a product, except for a few gas phase model reactions.

[...] I’d have thought that evolution would have selected for “simpler” pathways.

I just don't understand what you mean with simpler. Just because a molecule is more complex, it doesn't mean the pathway has to be more complex, too. Like an electric screwdriver is a lot more complex than a regular one, but the process of using the tool is similar, and the same result is achieved faster, and I would argue much simpler.

However, I am just one person, and, as is evident, there are some people who understood your question perfectly fine. Even as well as that they posted an answer to it. It is not the first time where this happens, and it will not be the last. That is why we have majority decisions and meta discussions.

Now back to meta:

With all due respect, what could possibly be the point of choking off inquiry in an area of knowledge where curiosity is typically celebrated?

First of all, nothing is set in stone here. Your question has been closed to allow it to be improved. It wasn't deleted, it doesn't even have a negative score. So I would say your inquiry wasn't choked off.

The Stack Exchange model is to be used as somewhat of a last resort. The more research went into asking a question, the better they are received by the community.
Chemistry.se doesn't aim to replicate content that is available in a more concise form somewhere else. It really is more for the hard to find stuff.

So while we do encourage curiosity, and sometimes even celebrate it, we also would like to make a strong case for self-study. If you are really curious, you have to help along with putting in some work yourself.

Why not err on the side of “clearly there are people that understand the question, so why not let people decide for themselves if the question is to broad?”

I am all for erring on the side of letting a question open. I have often voiced my concern that some questions get shut down prematurely.

Broad questions often attract broad answers, they often attract follow up questions, which will often be posted as answers by users unfamiliar with our site. All of which has to be dealt with down the line. If a question can be improved in a way that these things may be avoided, especially while all participants are still active, I am all for it.

I am sure your meta post will lead to some of our community members reconsider your question; maybe you'd even consider rewording it a bit. If all of that leads to a better findable and understandable Q&A, I'd say the system works fine.

meta-meta: If you want to notify the participants in the comments, prepend @ to their display name.

  • $\begingroup$ I read the ‘two’ as ‘two molecules’ in you first quoted extract. Somewhat unclear wording, yes. $\endgroup$
    – Jon Custer
    Commented Apr 15, 2020 at 17:47
  • $\begingroup$ @Jon Oh, I guess I understand; the probability of three molecules colliding is smaller than two molecules colliding; indeed, that is quite correct (in the gas phase). $\endgroup$ Commented Apr 16, 2020 at 1:00
  • $\begingroup$ @martin - I always do considerable research before asking a question (which is why I rarely have to ask a questions). The reason I had to ask this question is specifically because it’s a ”big picture” question that often isn’t answered in textbooks. $\endgroup$
    – Mike
    Commented Apr 17, 2020 at 9:54
  • $\begingroup$ @Mike We don't know what you know if you don't tell us. If you have done considerable research, include some of the key points in your post. It helps taylor answers to the problem at hand. $\endgroup$ Commented Apr 17, 2020 at 10:37
  • $\begingroup$ @martin - I guess my point is that I don’t see what the point is of preventing other people from answering the question by closing it. What does it hurt to leave it open? There are some people who knew exactly what I was asking, so why not let those that do understand the question answer it rather than let those who don’t close it? It makes absolutely no sense and the policy is frankly mind-boggling. What good does closing a question do anyway? What does it achieve? $\endgroup$
    – Mike
    Commented Apr 17, 2020 at 18:47
  • $\begingroup$ @Martin-マーチン, ignoring all the meta discussion (overly meta for my tastes), you may want to see the edited question, I think the phrasing has been considerably improved and Karsten has removed the phrases which you didn't like. chemistry.stackexchange.com/questions/131794/… $\endgroup$ Commented Apr 19, 2020 at 4:08
  • $\begingroup$ @orthocresol thanks for the update. There isn't anything that I can do now (of rather want to do, for the same reasons as you), but I agree that it's a solid candidate to be reopened. We a user I would vote so. $\endgroup$ Commented Apr 19, 2020 at 12:46

I’ve already received three answers (originally 4 but one was removed)

There aren't any deleted answers on your question; not even any deleted comments, as of the time of writing.

Why not err on the side of “clearly there are people that understand the question, so why not let people decide for themselves if the question is to broad?”

Well, that's sort of what happened: the community decided that the question was too broad. I didn't overrule them, nor did any other (diamond) moderator. It turns out that the community consists of quite a few people. Some thought it wasn't too broad and answered your question; some thought it was too broad and voted to close.

Other people's vote to close or reopen is not something that I can dictate. But I will add that in this case I don't personally agree with the closure.

Going back to my point about how the community consists of multiple people: you may well find that, especially after posting on meta, some other members of the community (perhaps including those who answered) may vote to reopen. I think this is quite a likely scenario. Your comment on your question probably won't do you many favours in this regard, though, so I would suggest retracting that. Your meta post is more than sufficient for bringing attention to the closure (and was the right thing to do in this situation).

  • $\begingroup$ I saw too late that one of the “answers” I thought was deleted was actually a comment (that wasn’t deleted). I guess I don’t understand why anyone would close that question (besides the obvious of it being too broad). It’s clearly a serious question not posted by an idiot or a troll. What good does it do anyone to close it? ..... $\endgroup$
    – Mike
    Commented Apr 17, 2020 at 10:04
  • $\begingroup$ Honestly, I’ve avoided joining SE because every time the site comes up in a google search, the answers are closed, or accused of being dupes (when they aren’t), etc. I’ve heard terrible things about the place on Reddit and I kind of see what they were saying (this isn’t aimed at you). The whole culture twists the virtue of precision into something that completely violates the spirit of inquiry in general and science in particular. $\endgroup$
    – Mike
    Commented Apr 17, 2020 at 10:05
  • $\begingroup$ Speaking as somebody who has used both websites for years - Reddit and SE serve very different purposes and consequently have quite different mechanisms for managing content. Question closure on SE serves as a way to maintain quality of questions, as well as answers (the latter perhaps being more important). There's a reason why people tend to copy code from Stack Overflow, not Reddit. Of course, Reddit is much better for open-ended discussions and general conversation. The problem is that many people (on both sites) do not understand that it's not a competition: each has a different niche. $\endgroup$ Commented Apr 19, 2020 at 3:44
  • $\begingroup$ Anyway, this is not the point of this discussion. To get back on track: even if I were to agree with your accusations, there is not much I can do. I only have "power" in a small section of SE, and even this is not real power. For example, I do not want to, and will not, reopen your question unilaterally, even though I can do so and I personally don't find any problem with your question. Quite clearly, multiple people disagree with me over this. It is not my job to overrule them. $\endgroup$ Commented Apr 19, 2020 at 3:51
  • $\begingroup$ Unfortunately, that is pretty much all I can say about it from my side. As a moderator I can't take any executive action on your behalf, even though as a user I would vote to reopen. The only way to get the outcome you want is to try and convince other people that the question has been wrongly closed. I don't think your approach of broadly questioning the policies and characteristics of the SE network are helpful in this regard. These have been argued to death and are unlikely to be fundamentally changed (and fwiw, I agree with them). It is better to focus on your specific question. $\endgroup$ Commented Apr 19, 2020 at 3:54

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