Are mutations truly random or are they guided?

Happens all the time, just look at many of the serendipitous advancements in science and technology. Wikipedia has quite a list.
Some examples on the list:
1. LSD
2. Silly Putty
3. Discovery of Helium
4. Penicillin
5. Viagra
6. Mechanism for inkjet printers
7. Microwave ovenGranted, most of the time, if you make a mistake while doing science, you'll probably just end up ruining your experiment. However, there will be the occasional time when you accidentally put B in with C instead of A and you get something no one has seen before. The chance of this happening to an individual at any given point in time is small, but the number of scientists and experiments is high enough that accidental advancements have been made numerous times. The same is true for mutations in DNA. The cellular machinery is remarkably good at what it does, but those few mistakes it makes, when you look at an entire population over the amount of time life has been around adds up to a LOT of mistakes. And the thing about beneficial ones is that once they arise they tend to stick around. How exactly would this work? How could a cell know to direct mutation? The only instance I can think of that is anything like this is bacteria that have increased mutation rates during stressful times. The idea is that with a higher mutation rate, the chance of coming across a beneficial mutation is higher. However, the mutation is still undirected and relies on chance. The ability to induce mutation is also, in an of itself mutation that arose by chance and the was selected for.When you say "it makes more sense..." have you really thought about it? How would an individual cell possess the forethought to make the correct mutations? I think it makes more sense that mutations arise randomly.

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We have many intuitions in our life and the point is that many of these intuitions are wrong. The question is, are we going to test those intuitions?
-Dan Ariely

Yes, but if that's all you have, that's all you can do. Individual cells do not possess the capacity for invention, they have no creative ability, so they rely on chance. It doesn't "know". The processes of the cell occur spontaneously. All of the reactions that happen in the cell are either thermodynamically favorable (exergonic) or are fueled by an outside source of energy. Either way, they occur simply as a consortium of biochemical reactions without any conscious thought. Cognitive function is an emergent property of groups of cells. It cannot exist within a single cell. I have a pretty good understanding, I am currently working towards my PhD in biology. Because, as I said, individual cells do not have knowledge, much less the creative capacity to guess at what they'll need. What you're implying is that a single cell has the ability not only to recognize that it needs to adapt, but has the knowledge of how a change in nucleotide sequence will alter the function of a protein. We can't even make those predictions.However, as I alluded to in my previous post, it is possible for mutations to occur nonrandomly, in a sense. For example,

quote:

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Molecular biology has demonstrated, however, that the rate and spectrum of mutations is in large part under the control of genetic factors. Because genetic factors are themselves the subject of adaptive evolution, this discovery has brought into question the random nature of mutagenesis. It would be highly adaptive for organisms inhabiting variable environments to modulate mutational dynamics in ways likely to produce necessary adaptive mutations in a timely fashion while limiting the generation of other, probably deleterious, mutations [. . .] Here, we review recent evidence for the existence of adaptively tuned mutation rates. We conclude that these mechanisms do not require any special foresight. Instead, they must have been selected for repeatedly in the past for their ability to generate genetic change. Mutational tuning does not require the specific generation of adaptive mutations (nonrandomness with respect to function) but rather the concentration of mutations under specific environmental conditions or in particular regions of the genome (nonrandomness with respect to time or location). Given a predictably variable environment, adaptively tuned mutation rates can evolve in ways completely consistent with the modern synthetic theory of evolution.

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SourceAs you can see in the text I've highlighted, cells can have control over where or when they increase mutation rates, but they still rely on the random chance that the mutations that happen are beneficial.So to sum up: cells cannot influence the kind of adaptation that a mutation presents, they can only sometimes influence the location in the genome or the rate at which they occur.

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We have many intuitions in our life and the point is that many of these intuitions are wrong. The question is, are we going to test those intuitions?
-Dan Ariely

True, which is why I originally said, A big component determining the difference between life and non-life (and, to be clear, I'm not saying it's the only difference) is controlled conversion and use of energy. The ATP used to fuel cellular reactions initially came from some outside source. But unless you're implying that there is some mysterious life-force, the reactions in a living cell are no different at the basic chemical level than they are in a test tube.
I'm not saying that cellular processes are not incredibly complex, because they are. They are also directed and regulated by cell proteins. But at the most fundamental level, the interactions between molecules, e.g. between enzymes and reagents, is random. An enzyme does not "seek" out it's target they same way we would. It floats around until it makes contact with it's reagents and then catalyzes a reaction. The probability of this chance meeting can be increased a number of ways, an example of which would be compartmentalization. The development of a cell is indeed deterministic, and most cells do it very well, with very few mistakes. But that doesn't mean a cell can direct itself to mutate in a particular way. As I stated before in reference to that paper on nonrandom mutation, the only way a cell can direct mutation is to change mutation rate or differ mutation rates in various regions of the genome. However, though a cell contains information, it does not have the ability to UNDERSTAND how everything works. A cell cannot know that changing A to C or G to T in a sequence will change the resulting peptide in a particular way. It's just not possible. So, a cell cannot pick and choose the mutations it will get. If they get a mutation that is lethal, the cell will die; if it's deleterious, it will be outcompeted. What's left will be the lucky cells that got beneficial or neutral mutations. That's evolution.

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We have many intuitions in our life and the point is that many of these intuitions are wrong. The question is, are we going to test those intuitions?
-Dan Ariely