That's a very interesting post!! Thank you for the enlightenment.

For understanding the idea the lock*key model works very well I think. I mean, it gets hard if you take into acount that most ligands don't bind covalently and attach/detach based on chemical properties that we -for simplicity's sake- call affinity. It brings in a lot of very specific kinetics that aren't usefull for understanding the basic concepts.

If OP goes deeper into biochemistry those factors will start to play a role and will be introduced bit by bit to keep it doable. A reddit post isn't really the place for that level of detail imho.

The way they track these mutations in time is by creating a huge family tree and puzzling the way back up. If a group of people is known to have split up e.g. 5000 years ago and none of them have that mutation, it likely occured less than 5000 years ago in the main population. It's not perfect but with enough samples and meta info we can create accurate philogenetic trees.

It also helps a lot that we have found a couple mummified people with intact DNA from different places and points in time.

Probably not. As in: most of our DNA is (near) identical but our phenotypic traits are determined by more than just the DNA. In a DNA test we don't look at the identical bits, we pinpoint for the more variable regions and repititions.

A funfact, there are animals that look very similar but are genetically extremely far apart. Different genes can result in similar traits in a completely different way. I can't remember the example my prof used in college but it was super interesting.

Short answer: no.

but some mutations are more likely in smokers, others in drinkers, drug users etc etc etc. A whole bunch of statistics can show these patterns.

Back from patterns to the individual; Definite proof that your tumor came from smoking is, again, not possible. But it's a likely factor that had an influence.

One other important factor involved is not based on the severity of the disease, nor the targetability of it. It's cost related. Anything that threatens "the west" gets more attention than diseases in e.g. subsaharan Africa because there is more money to make in richer countries.

I work at a company that develops immuno therapies for (initially) late stage (insert type, I can't tell, sorry) cancer. Our antibodies could be designed against basically anything but we picked a target that's not too crowded on the market and affects enough people that we expect to earn back our research investments and make some profit to invest in new therapies.

>That’s a bit different from what OP was asking.

I'm aware, that's why it was a reply to the mention of that assay and not a direct post towards OP. I work with TM-proteins and do quite a lot of labeled Ab assays to indirectly prove something's there as it's just too small to see;)

You can do this without a microscope as well, I've done this in uni somewhere in my first year. It's very easy and quick indeed.

Also, antibodies bind "somewhere" on their target. That target may be a specific part of one protein found in humans only, but they could be aspecific or bind a protein part wich's the same in another animal. Bioinformatics can help you for your specific antibody but wet lab testing's the way to go

Entropy just is, it's not trying anything. Same for nature.

Cells actively remove proteins which arem't needed anymore. E.g. Ubiquitin gets attached so the proteasome can recognise them and break them down. Protein decay happens over time as well but that's also a good thing for cells. It's part of the waste management to keep cells from getting stuffed with old proteins that can aggregate together.

So no, they are not destroyed faster than they can be built. There's a whole system in place to determine what needs to go when.

Your question's very weird honestly. It's completely unfocused and therefore really hard to answer satisfactory.

First, There are very many different proteins with different functions. They look nothing alike. So yes, some are stretchy or bendable, some are easy to manufacture. Others, not so much.

You learned DNA/RNA, those are like a prescription/recipe on how to form a protein. They're "just a strain of repeated units than can be read by ribosomes" (for simplicity's sake we stick to the highschool explanation here).

The ribosomes "read" the recipe and built the protein strand, which starts out as a long chain of amino acids. Each amino acid has its own unique characteristics like pH or sulpher atoms. When connected into a strand, those characteristics influence nearby amino acids to bend away or towards them. Polarity and Hydrogen and sulpher bridges shape the strand into a 3D structure. This is the "why": interactions make it that way. That kinda answers your question as well.

The last answer is "because it works". Proteins which are useless and cost energy to make or have a cool function but cannot be broken down afterwards affect the cell negatively. Efficient cells on average do better than inefficient ones, so good traits survive in the long run (yes, again, I simplify). Structures that work well are conserved throughout evolution, hence why we can make whole trees based on similarity. Which is also a reason why they're structural (and even more so than based on sequence similarity alone)

Microbiologist here (so no cancer expert!)

Some molecules are more stable than others. As you already mentioned, DNA can be damaged by radiation as energy is taken up by the DNA molecule and then it can fall apart or create new bindings.

Long story short, food molecules can (during their metabolism) turn into highly reactive particles that can damage your cells and DNA. Especially oxygen radicals can cause a lot of damage.

There's gotta be a YT video explaining this a bit more in depth.