Patrick Powers
Jul2-04, 05:32 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n>Hi:\n\n>As is well known - Free energy (G) refers to the maximum amount of\n>energy free to do useful work. It is related to enthalpy (H),\n>temperature (T), and entropy (S) by :\n\n>delta G = delta H - T delta S\n\n>Free energy is also a measure of spontaneity. Negative values of G\n>indicate a spontaneous or forward (reactants make products) reaction.\n>Positive values of G indicate a nonspontaneous or reverse (products\nmake\n>reactants)system. If G = 0, the system is in equilibrium, where there\nis\n>no forward or reverse reaction. At equilibrium, the composition of\nthe\n>system (amount of products and reactants) is constant.\n\n>Now in the context of chirality, I believe it has been experimentally\n>proven that there is a difference in entropy between separate\n>enantomeric forms and the racemic mixture of these two forms and this\n>can quantitatively be expressed in terms of entropic mixing.\n\n>delta S = - R summation Xi ln Xi\n\n>where Xi whole be enantomeric chiral forms.\n\n>I am wondering if such is the reason for the predominance of chiral\n>forms in biological entities (plants, fungi, insects and man).\n\nYes, but there is nothing subtle about it. Carbon chains are chiral\nby nature. An enzyme is a big carbon chain molecule that catalyzes\nreactions by virtue of its shape. It provides a suitable site for a\nreaction to occur and may actually shift to bring the reactants\ntogether in the desired way. An enzyme of different chirality is a\ndifferent shape. So while different chiralities of the same molecule\nmight seem related from the point of view of a chemist, to nature they\nare different shapes and not particularly related.\n\n> The\n>enantomeric chiral form provides a shift in entropy and the\n>corresponding negative free energy for life to proceed in the\nbackground\n>of all things going in increasing entropy direction.\n\n>Just looking for some thoughts in this matter.\n\n>Richard Saam\n\nNow, you could reflect all of biology in a mirror and come up with\nlife of the opposite chirality. The existing chirality for DNA is\nslightly energetically favorable, so we suppose this is why it\ndominates.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>>Hi:
>As is well known - Free energy (G) refers to the maximum amount of
>energy free to do useful work. It is related to enthalpy (H),
>temperature (T), and entropy (S) by :
>\delta G = \delta H - T \delta S
>Free energy is also a measure of spontaneity. Negative values of G
>indicate a spontaneous or forward (reactants make products) reaction.
>Positive values of G indicate a nonspontaneous or reverse (products
make
>reactants)system. If G = 0, the system is in equilibrium, where there
is
>no forward or reverse reaction. At equilibrium, the composition of
the
>system (amount of products and reactants) is constant.
>Now in the context of chirality, I believe it has been experimentally
>proven that there is a difference in entropy between separate
>enantomeric forms and the racemic mixture of these two forms and this
>can quantitatively be expressed in terms of entropic mixing.
>\delta S = - R[/itex] summation [itex]\Xi ln \Xi
>where \Xi whole be enantomeric chiral forms.
>I am wondering if such is the reason for the predominance of chiral
>forms in biological entities (plants, fungi, insects and man).
Yes, but there is nothing subtle about it. Carbon chains are chiral
by nature. An enzyme is a big carbon chain molecule that catalyzes
reactions by virtue of its shape. It provides a suitable site for a
reaction to occur and may actually shift to bring the reactants
together in the desired way. An enzyme of different chirality is a
different shape. So while different chiralities of the same molecule
might seem related from the point of view of a chemist, to nature they
are different shapes and not particularly related.
> The
>enantomeric chiral form provides a shift in entropy and the
>corresponding negative free energy for life to proceed in the
background
>of all things going in increasing entropy direction.
>Just looking for some thoughts in this matter.
>Richard Saam
Now, you could reflect all of biology in a mirror and come up with
life of the opposite chirality. The existing chirality for DNA is
slightly energetically favorable, so we suppose this is why it
dominates.
>As is well known - Free energy (G) refers to the maximum amount of
>energy free to do useful work. It is related to enthalpy (H),
>temperature (T), and entropy (S) by :
>\delta G = \delta H - T \delta S
>Free energy is also a measure of spontaneity. Negative values of G
>indicate a spontaneous or forward (reactants make products) reaction.
>Positive values of G indicate a nonspontaneous or reverse (products
make
>reactants)system. If G = 0, the system is in equilibrium, where there
is
>no forward or reverse reaction. At equilibrium, the composition of
the
>system (amount of products and reactants) is constant.
>Now in the context of chirality, I believe it has been experimentally
>proven that there is a difference in entropy between separate
>enantomeric forms and the racemic mixture of these two forms and this
>can quantitatively be expressed in terms of entropic mixing.
>\delta S = - R[/itex] summation [itex]\Xi ln \Xi
>where \Xi whole be enantomeric chiral forms.
>I am wondering if such is the reason for the predominance of chiral
>forms in biological entities (plants, fungi, insects and man).
Yes, but there is nothing subtle about it. Carbon chains are chiral
by nature. An enzyme is a big carbon chain molecule that catalyzes
reactions by virtue of its shape. It provides a suitable site for a
reaction to occur and may actually shift to bring the reactants
together in the desired way. An enzyme of different chirality is a
different shape. So while different chiralities of the same molecule
might seem related from the point of view of a chemist, to nature they
are different shapes and not particularly related.
> The
>enantomeric chiral form provides a shift in entropy and the
>corresponding negative free energy for life to proceed in the
background
>of all things going in increasing entropy direction.
>Just looking for some thoughts in this matter.
>Richard Saam
Now, you could reflect all of biology in a mirror and come up with
life of the opposite chirality. The existing chirality for DNA is
slightly energetically favorable, so we suppose this is why it
dominates.