DNA - So how does it ACTUALLY work?

[Dean Watson]

Hello all, genuine question as Im curious to understand the mechanism (just been reading Sagans 'Shadows of Forgotten Ancestors') and haven't yet been able to get an explanation, let alone one I understand.  Now, of course I get all the stuff about it being a 'code' for a given lifeform etc etc, and the composition of it from the four nucleotides (GATC), double helix form and whatnot.

 

What ive yet to understand (and I concede the answer may in fact involve in taking a prolonged course in genetics, although to coin Feynman, any concept should be easily explainable to a layman in a few sentences otherwise its not really understood) is how the actual PHYSICAL (for that is what it is) structure of the four nucleotides making up the DNA molecule, other than being of course a form of code, ACTUALLY go about creating and/or being part of the again PHYSICAL structures and by extension encode, the individual cells of an organism, not only so that those cells perform different tasks but also contain in their nucleus a copy of that DNA.

 

As I say, the code bit I get, what I don't understand is how it goes about creating the actual physical structures its encoding for as a result. Because its not just code in the computer sense, its actual complex molecules and they must logically have a physical/chemical way of creating the 'higher' structures they go on to form.

 

My initial thought is that the structure of the code becomes the actual physical proteins that themselves become tools for building higher structures but that's just an educated guess inferred from what Ive been reading?

 

Thanks all - A little curiosity is a dangerous thing! Oh and, hate to sound prissy but if you actually don't know, please don't guess here, I would genuinely like to understand it but don't know enough to tell the difference between supposition and actual fact.

 

Ta all!  I suspect this wont be a long thread!

 

 

[Brantuk]

There was a great article on the origin and development of life including an excellent explanation of dna sequencing on the BBC website a couple of weeks ago. It was long but really easy reading and highly explanatory - had me riveted for hours it did cos I've always sought a decent understandable account of this myself. I'll see if I can find a link for you - but not looking good so far - dunno if it's still there or not.

(It was in the science section)

Edited January 19, 2017 by Brantuk

[Dean Watson]

47 minutes ago, Brantuk said:

There was a great article on the origin and development of life including an excellent explanation of dna sequencing on the BBC website a couple of weeks ago. It was long but really easy reading and highly explanatory - had me riveted for hours it did cos I've always sought a decent understandable account of this myself. I'll see if I can find a link for you - but not looking good so far - dunno if it's still there or not.

(It was in the science section)

I think I saw that myself Kim - thing is, ive seen much of that elsewhere- what I wanted to understand was the actual physical/chemical mechanism whereby that code translated itself from its own physical structure/code into that of the cell/organism.  I suspect it is to understate, rather complex...

[Brantuk]

Ahh... just as well you saw it already - I can't find it anywhere on the Beeb website now. I agree though - the bit that described how the helix splits and bits join up like a jigsaw to go specific, didn't really describe the precise mechanism that initiates and sustains it all. But it's always been a keen interest of mine so do please let me know if you come up with anything.

[Sheila]

yes you are correct, you would need to go into a higher biology course to go through all this.  It is quite complex and involves three types of RNA,

plus loads of other mechanisms and enzymes to code for all the other stuff.  It is not a short answer    DNA codes for everything and can replicate itself.  Sections can be copied by RNA for

other stuff.  That's as simple as it gets (and simple quite often is not enough) but does not give you the whole story nor all the bits in between

 

Sheila

[Dean Watson]

1 hour ago, Sheila said:

yes you are correct, you would need to go into a higher biology course to go through all this.  It is quite complex and involves three types of RNA,

plus loads of other mechanisms and enzymes to code for all the other stuff.  It is not a short answer    DNA codes for everything and can replicate itself.  Sections can be copied by RNA for

other stuff.  That's as simple as it gets (and simple quite often is not enough) but does not give you the whole story nor all the bits in between

 

Sheila

Thanks Sheila - So from what I read (and I accept that I may be using the wrong terms, language, possibly even reasoning) would I be sort of along the right lines to suggest that the inherent composition of the code (and by which I mean the nucleotides its composed of) in effect are tools in their own right that go on to make more complex tools and functionality for whatever purpose that code is 'intended' (Intelligent design! Don't get me started, we'll be on moon landing hoax before you know it!) for and that leads by inevitable progression to the cell/organism?

 

Now get me on imaging with a DSLR and I know what I'm talking about!

[Sheila]

in a simple nutshell yes    I will not get started on intelligent design either  

[Smithysteve]

You might find this book by Nick Lane, interesting Dean, 'Life Ascending - The Ten great inventions of Evolution'.

 

It covers the conditions for start up of life and builds up to RNA DNA etc. It's a fascinating read. It gives you a handle on lots of the basic terminology too!

 

i am interested in physics and stuff so not really covered the biology side. This is a good place to start... its filling a good few gaps for me!

 

i also have bought the latest book by Nick - The Vital Question ... cannot wait to read it - see what you think. ?

 

[Dean Watson]

On 08 February 2017 at 14:22, Smithysteve said:

You might find this book by Nick Lane, interesting Dean, 'Life Ascending - The Ten great inventions of Evolution'.

 

It covers the conditions for start up of life and builds up to RNA DNA etc. It's a fascinating read. It gives you a handle on lots of the basic terminology too!

 

i am interested in physics and stuff so not really covered the biology side. This is a good place to start... its filling a good few gaps for me!

 

i also have bought the latest book by Nick - The Vital Question ... cannot wait to read it - see what you think. ?

 

Thanks Steve.  I'll look - See, I was aware of the double helix, nucleotides and whatnot but what I was curious as to was given that DNA is an actual physical structure, as well as being a code, how does that structure, as it were, upgrade itself to become the actual cell and then from there organism.  The chemicals it is composed of have an actual physical effect and I was wondering how that physical effect 'unzipped'  (in the same sense as winzip, not the unzipping of the helix!) to become the structure it codes for.

 

The thing I love about astronomy though is that it takes you in all sorts of directions.  Consequently I'm interested in anything from evolutionary biology to the Wars of the Roses,  human and other animal behaviour to British sitcoms.  The world is fascinating.  Impossible to be bored.