This is the sum of work energy and heat energy in the system
U= w+q
The total energy of a system is its internal energy
Kinetic energy - For a particle with mass and velolicty can use Kinetic energy
Ke= 1/2mv^2
Potential energy - Graviattional potential energy and chemical bond energy, which is the energy stored in chemical bonds that is released when bonds broken and cleaved when bonds made
Open- Both energy and matter can enter and leave the system
Closed- Only energy can enter and leave the system to the surroundings
Isolated - Neither matter nor energy can be transferred from system to the surroundings
The sum of energies in a system and its surroundings is a constant as energy cant be created or destroyed only tranferred as different energy forms
Work is a process in order to lift a weight and when it is perfomed energy is transferred to the surroundings
Work = Force x Distance - where Force = mass x acceleration
Q= M x C x Delta T
A hot system in contact with a colder surrounding will sponteneously get colder but the opposute will not happen
This is called the enthalpy of the reaction
Enthalpy = H = U + pV
Change of enthalpy = Delta U + Delta pV
This simplify relations between measurement of energy and measurable quantity
DeltaH= Delta U + pDeltaV = Delta work + Delta q + pDeltaV
So at constant pressure
DeltaH = -pDeltaV + delta Q + pDeltaV = Delta q
This means Delta q = enthalpy change
Endothermic have a + Delta H so more energy enter the system that leaves it
Exothermic have a -Delta H so more energy leave the system than enters is
Use a Bomb calorimeter due an exothermic reaxction will increase temp so can then use
q=mcDeltaT
Then Delta H = q/n
In an isolated system the entropy can omly ever increase and so a hot system in a cold surrounding wil only gte colder and at the same time the surrounding will get hotter, camt happen other way round
Change of entropy is proportional to the heat transferred from the system to the surroundings
Delta S = DeltaQ/T
at equlibrium Delta S = Delta q/T
However due to Delta Q = Delta H
Then entropy = Delta H / T
In an exothermic reaction the entropy will decrease but surroundings entropy will increase
In an endothermic reaction the entropy of the system wil increase but trhe entropy of the surroudnings will decrease
The entropy has to increase for a reaction to be spontaneous and has to be in btoh the system and the surroundings
A macrostate = Temperature, Volume , Pressure
A microstate = Kinetic energy, force and mainly the number of configurations of all the particles in the system
A macrostate can be described as a collection of microstates
The number of microstates in a system
S= Kb x ln(Microstate number )
Kb= Boltzmann constant
For an isolated system in thermla equilibrium all microstates are equaly likel;y to happen
The equilobrium state is thet state in the system with the most microstates
Obsevred tendency of non-polar substances to aggragtes in aqueous solution
It is used to stabilise the phospholipid bilayer and also will drive proteins to fold inot 3 dimensioanl structure so they can function
It is driven by hydrophobic collapse and so the hydrophobic sdie chains are buried in the 3d structure
The unfolded state has many different conformation so large entropy compared to the folded state
Entropy wil favour the mixing of substances as there are more ways to arrange the molecules so a greater entropy
The enthalpy of the mixing is determined by the intercation between the molecules
= Gain enthalpy of A bonding to B and lose enthalpy of A bonding to A and B bonding to B
Ion- dipole, H bond, Dipole - dipole, Ion inducved dipole, Dipo,e induced dipole and disersion forces
They can all do work or can gain work from them
In a solution of water each molecule will have 4 neighbourghs so a tetrahedral bonding shape
There will be 2 hydrogen bonds formed
We can arrange the molecules of the water in the tetrahedral bonding shspe in 6 different ways to maintain 2 hydorgne bonds to be formed
This means 6 microstates
If replace a water molecule in the solution with a methyl group then does not allow formation of hydrogne bonds so only 3 microstates can be formed for the central water molecule
= 3 microstates
Can use entropy in water - entropy in other environment
Delta S = Kb x (ln microstate in water - ln microstate of other enviornment)
It will minimise the exposure of hydrovarbon chains to the water so then maximise the entropy of water in the presence of phospholipid
The energy from a reaction that is availble to generate work
DeltaG= DeltaH - TdeltaS
For a reaction to be spontaneous then Delta G needs to be a negative number as the gibbrs energy of the product is less then the gibbs free energy of the reactants
At equilibrium the concentration of reactants and products are related by Q which= Kc the equilibrium constant
Kc= [Product]/[Reactants]
If Kc larger than Q then reaction proceed left to right favoruing the products
If Q larger than Kc then reactiom favours the reactants and go right to left
For Q =[A]/[B]
Then at - delta G = A is greater than B
Id Delta G= 0 then at equilibrium
If Delta G is + then B is greater than A so
Delta G = Delta Go(Gibbs free energy) + RT ln(Q)
At equilobrium the Delta G (standard state ) and Q=KC
So Delta G = -RT kn(Kc)
Delta G = reaction mixtured in standard states
Life - The properties that distinguish the living organisms from dead organaims and inaminate objects
Control- The turning on or off of specific genes, cellular pathwasys or the function of enzymes
This occurs when thing intercat with each other in bioloigical systems with receptors, it is controlled by weak non-covalent interaction between the molecuels
Kinetics - The rate at which soemthing appears or disappears
Affinity - The stregnth of the intermolecular forces between the ligand the protein receptor
As the protein receptor and the ligand associate together to get a constant
= [Complex]/ [receptor]x[ligand]
The inverse of the association constant so a constant for when the ligand and protein unbind from each other
[Protein receptor] x [ Ligand ] / [ Complex ]
For association = Delta G = -RT x ln(Ka)
For Dissociation = Delta G = +RT x ln(kd)
Detect a radio labelled lignad
Mix with the unradiolabelled ligand that is chemically indentical to it
Add a sampole and reach the equlibrium in the system
Seperate the bonded ligand from the unbound lingand and measure the total boud with liquid scintillation counter
Ligands with a low Kd will be tightly bound to the protein and Ligand with a high Kd will bind weakly to the protein receptor
When ligand = 4 x Kd then 80% of the receptor are occupied
When liagnd = 9 x Kd then 90% of the receptors are occupied
Takes 99 x Kd to fill all the receptors
[ Bound receptor ] / [Free and bound receptors ]
All receptors are equallty accessible to ligands - they are not
All receptors are either free or bound to the ligand - Ignore state of partial bound in model
Neither ligand or receptor are altered in binding
Binding is reversible
Must be measured at constant temperature and is a regular hyperabola shape
Deviation from the curve due to multiple binding sites or different affinities or allosteric regulation