BIOC2000 Lecture Notes - Lecture 6: Ribose, Adenine, Cytosine
Lecture 6
HIGH ENERGY MOLECULES
How can we force a reaction with a +ΔG to proceed?
ΔG = ΔH - T ΔS
The T value in the Gibbs Free Energy equation is limited by the
temperatures under which a system can exist.
This means that we can’t rely on extreme temperatures to drive or facilitate
reactions in our bodies. Therefore we have to rely on changes in enthalpy
(ΔH) and entropy (ΔS)
ATP – the grand master of energy carriers
- Drawing ‘engine-part’ of ATP : “OPOPOPO”
** Oxygen circled is the
difference between DNA and
RNA – in DNA it’s just an H
** Could draw ‘Ribose’ and
adenine in boxes [Ribose]-
[Adenine] – fine
Not all enzymes use ATP, some
use GTP or CTP (guanine
triphosphate, cytosine
triphosphate)
• ATP is commonly found in
cells – not necessarily for
energy – to make DNA, RNA also
• This structure doesn’t have any ‘particular bond’ that is a ‘high
energy bond’
• Energy is in the arrangement of the structure – and the release of
that arrangement because it is thermodynamically unstable – high
energy group - because when broken, a lot happens that causes a
negative ΔG
• unsatisfied O - P
does not have enough to
give every O 1 electron – O
on P are pulling on the
electrons – mixture of
negative charge around
structure – all negative
charges are close together
– like charges repel
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Document Summary
The t value in the gibbs free energy equation is limited by the temperatures under which a system can exist. This means that we can"t rely on extreme temperatures to drive or facilitate reactions in our bodies. Therefore we have to rely on changes in enthalpy ( h) and entropy ( s) Atp the grand master of energy carriers. ** oxygen circled is the difference between dna and. Rna in dna it"s just an h. ** could draw ribose" and adenine in boxes [ribose]- Low resonance (in a p group by itself, electron shared back and forth) thus low entropy. Q: what do you notice about the electronic arrangement on po4. Resonance (electron-sharing) occurs a lot when phosphate group is released. Disorder of electrons from triphosphate to mono-phosphate increases. O pulling on electrons off of p (which has pretty much lost use of its electrons to these o around it) p is in the middle naked" exposed nucleus.
