Notesale: Turn your study into money

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Living vs non living are not distinguable by the chemicals that compose them but by the
realtive abondance of these elements

2
...
Oligo-elements : Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, I : vitale roles

Carbon: key element in molecules diversity
Carbon bounds(2,3,4) : Affect the geometry (Bound length, strength, electronegativity) =
Activity of biomolecule
***Unique prpt of C: Build molecules of differnet shapes: Chains, branched chains, Cyclic
strs
...
) or to build up other molecules (Anabolism)
Metabolism = Anabolism + Catabolism
Classification

Energy : Source of energy
Carbon: Source of carbon atoms to build complex mol

The flow of matter is cyclical : Autotophs generate
organic mol and O2 : Used by Heterotrophs
Heterotrophs produce H2O and CO2 : Used by
Autotrophs
*The flow of ennergy is irreversible: Most of it is from
the sun : Part of it is captured by photosynthetic
organism
*Other autotrophs receive energy from chemical
compounds
*** This energy is converted into chemical energy
usable by both auto/heterotrophs
This energy can not be used totaly : Some of it is lost as
a heat
What is Energy
Energy : The capacity to do Work
Living organism = Obey the laws of thermodynamics
#1st law: The universe contain a constant amount of energy : Energy is not created nor
destroyed but it can change form
#2nd law: Energy is transfered the way increases the randomness (Entropy) of the univers
Entropy change = Change of various forms of energy into thermal energy

Question: Since our bodies r highly organized, aren't we breaking the second law of
thermodynamics
Answer: No, the entropy complies for the whole universe not on an isolated system, besides
the heat produced during metabolism contibutes to increase the entropy
Gibb's free energy equation : Fundamental to describe thermodynamics
G: Free energy available to do work : Usable
H: Total energy of the system (Energy of chemical bounds of
all the reagents + energy of the envirement)
T: Temperature
S: Quentitaive expression of the randomness of the system
TS: The disorder of the system(can not do work) : Inc in T
intensify S (Inc random motion of mol)

Free energy = FE
Reaction
= Rec
Equilibrium
= Equi
What drives a bio molecule to be transformed (envolved in a reaction)
a sys rich of FE is unstable and spontaneously evolves to a more stable state(lower FE)
*Spontaneous(Exergonic) Rec is characterized by Dec in FE = Thermodynamically favorable

Substrate with high potential energy is converted into a
production with low potential energy
Thus : the change in FE is negative ΔG<0
Exothermic reaction if produces heat
Endothermic reaction if consumes heat
and vice versa for Endergonic (non spontaneous re action)
Characteristics of biochemical Rec
1
...
Equilibrium Cte
o The net change of sub and products is null
o the velocity of direct=velocity of indirect Rec
o Equilibrium Cte = The ratio of [Prod]/[Sub]=Cte
3
...
Velocity
NB: almost all cellular reactions are prevented from equi state (maintained near equil)

Relation between equi and FE

*Standard free energy change
*Actual free energy change
* Relation between equi and FE (at equil delta-G=0)



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