Researchers are able to synthesize any complex molecules

[scott_alexsk]

How is it that researchers are able to synthesize any complex molocuel, and know what it does? I mean is it just through random discoveries that biology is advancing or is there some other way? It is just the complexity of polymers is so great especially in cells. Even for relatively simple polymers like rubber, I just learned, researchers are still debating its form.
Thanks,
-Scott

 

[Monique]

There are many ways, you for instance can look where the molecule localizes in the cell (nucleus vs cytoplasm for instance) and you can look what happens when you inactivate the molecule or bring it to over-expression, also the structure can give you information (if every 7th amino-acid in a protein is hydrophobic, you're likely dealing with a coiled coil).

The development of new drugs is still a large process of chance, companies screen very large libraries of compounds to see whether there is any interaction with the molecule of interest. People are trying whether they can predict what molecule would work as a drug, but they have not been very succesful. I believe there are only very few designed drugs and those have been used for other tasks that originally thought (Gleevec comes to mind).

 

[scott_alexsk]

How are researchers even able to isolate compounds of interest? Or are there even no compounds of interest, just what researchers manage to isolate?
Thanks,
-Scott

 

[Mike H]

If you can isolate it, it's probably interesting somehow. You just need to figure out how.

As for how new things get isolated...same as with any other molecule. You know what it does - so you have some sort of assay - so you can use that to test your purification procedure. Run a column? Does the interesting activity lie with the material that flows right through or does it come off as you elute material from the column? Salt out your solution by adding lots of ammonium chloride? You check and see the precipitate and supernatant at each step. You run a distillation column? You check and see when what you're distilling no longer has the activity and is now condensed out from the fumes up top. It's a matter of trial and error, some scientific common sense (probably best to run things like centrifugations and dialysis steps early, very specific columns later on), and intuition.

But it can be awfully fun, even if you supposedly have a reliable protocol that you should be able to trust. :)

 

[scott_alexsk]

So is that the story of how researchers are able to understand cells better? Is it that they just pull out random molocuels, see what happens if they remove it, or add a bunch of it, determine its purpose from that and then move on? Of the total known chemical pathways within a cell, what percent would you say are known by science?
Thanks,
-Scott

 

[Monique]

There are many different efforts to understand the cell as a whole. There are chips available that contain every single expressed sequence of the genome, with those you can test exactly what genes are expressed in the cell and how that changes over time or under different conditions. You can also look at all the proteins in a cell and what happens to them over time etc.

Then there are efforts that are mapping the interactions of all the different proteins in the cell, to visualize the different networks. You have got worms where you can knockdown different genes and observe the phenotype that appears, for instance that a gene is required for embryonic development.

You can make analyzes across species, to see what genes are conserved. You can look at genotypes and see whether people with a certain mutation have a higher risk for disease.