Venki Ramakrishnan

And yes, it's stochastic in the sense binding is stochastic. But there is a deterministic... direction to it. And that's because energy is used at each step. And that's what thermodynamically drives it forward in the forward direction.

And yes, it's stochastic in the sense binding is stochastic. But there is a deterministic... direction to it. And that's because energy is used at each step. And that's what thermodynamically drives it forward in the forward direction.

Yeah, so the fact that ribosomes can crystallize suggests that ribosomes are largely identical But there's now a debate in the field.

Yeah, so the fact that ribosomes can crystallize suggests that ribosomes are largely identical But there's now a debate in the field.

There are a group of scientists who believe that ribosomes can be specialized, that in some cells you may get subsets of ribosomes which translate particular mRNAs or translate under certain, you know, translate meaning translate the genetic information into protein. So that they work under certain circumstances. And this field of specialized ribosomes is still somewhat controversial.

There are a group of scientists who believe that ribosomes can be specialized, that in some cells you may get subsets of ribosomes which translate particular mRNAs or translate under certain, you know, translate meaning translate the genetic information into protein. So that they work under certain circumstances. And this field of specialized ribosomes is still somewhat controversial.

But it does have some strong advocates. And I think... I would say the jury's still out, but there is some evidence for specialized ribosomes.

But it does have some strong advocates. And I think... I would say the jury's still out, but there is some evidence for specialized ribosomes.

Very similar. They're not exactly the same because there'll be small genetic differences. So just like, you know, for example, a mouse may be well over 95% or so identical to in some ways to humans. But of course, that same degree will apply to ribosomes and ribosomal proteins. But I will tell you one thing, the core of the ribosome, the part where the amino acids are joined,

Very similar. They're not exactly the same because there'll be small genetic differences. So just like, you know, for example, a mouse may be well over 95% or so identical to in some ways to humans. But of course, that same degree will apply to ribosomes and ribosomal proteins. But I will tell you one thing, the core of the ribosome, the part where the amino acids are joined,

to during stitching together a growing protein chain, you're going to add amino acids to the growing protein chain because amino acids are the building blocks. So that part where it's joined or the part where the genetic code is recognized in the ribosome, those parts are highly conserved. They're even conserved across kingdoms.

to during stitching together a growing protein chain, you're going to add amino acids to the growing protein chain because amino acids are the building blocks. So that part where it's joined or the part where the genetic code is recognized in the ribosome, those parts are highly conserved. They're even conserved across kingdoms.

So there are only very small differences in the so-called peptidyl transfer center, which is where the amino acid bond is formed, peptide bond is formed. There are very subtle differences between, say, bacteria and humans. But overall, the ribosomes of bacteria look very different. For example, the human ribosomes are...

So there are only very small differences in the so-called peptidyl transfer center, which is where the amino acid bond is formed, peptide bond is formed. There are very subtle differences between, say, bacteria and humans. But overall, the ribosomes of bacteria look very different. For example, the human ribosomes are...

almost twice as large, and they've expanded both their RNA and protein components considerably.

almost twice as large, and they've expanded both their RNA and protein components considerably.

Environmental factors, viruses. So I think part of the reason that eukaryotic, that is a translation in higher organisms, with a nucleus is more complicated, is because there's more regulation in higher organisms. And Initially, biologists thought that almost all of the regulation of genes had to do with how much and when you made mRNA from a section of DNA.

Environmental factors, viruses. So I think part of the reason that eukaryotic, that is a translation in higher organisms, with a nucleus is more complicated, is because there's more regulation in higher organisms. And Initially, biologists thought that almost all of the regulation of genes had to do with how much and when you made mRNA from a section of DNA.

And that once the mRNA was made, the ribosome inevitably had to just do its thing, almost like a slave. But that's not how it is. It turns out that control exists both... at the mRNA production level, but also at the protein production level. So what we call translational control. And this means that the cell has ways of deciding when to start making proteins.

And that once the mRNA was made, the ribosome inevitably had to just do its thing, almost like a slave. But that's not how it is. It turns out that control exists both... at the mRNA production level, but also at the protein production level. So what we call translational control. And this means that the cell has ways of deciding when to start making proteins.