Bioenergetics 2 - Free Energy & Entropy Flashcards
Changes in enthalpy involve ……………….. and ………………… energy.
HINT: an example is that in the change of glucose to lactate, not all of the -50kJmol-1 are used in cellular proccesses and metabolism.
Useful, useless.
What is this equation? What TWO things does it relate to (G and S)?:
ΔG = ΔH - TΔS
Gibbs-Helmholtz equation.
G = free energy.
S = entropy.
In biochemistry, if ΔG (free energy) is less than 0, what happens?
If ΔG is less than 0, reactants convert into products and the forward reaction is favoured.
In biochemistry, if ΔG (free energy) is greater than 0, what happens.
The reverse reaction is favoured and products convert back into reactants.
In biochemistry, what happens if ΔG = 0?
There is equilibrium; the rate of the forward reaction is equal to the rate of the reverse reaction.
In metabolic pathways, do reactions tend to be reversible or irreversible?
Irreversible.
What can be thought of as ‘waste’ or ‘negative’ energy and is related to disorder and probability?
Entropy.
As well as changes in energy, entropy can be thought of as changes in…?
Matter.
In biological reactions, it is important that the amount of entropy is…?
Balanced.
This is an example of entropy…:
If glucose is contained in large sugar crystals, …………….. is happening and entropy is ………… .
If the glucose is in much smaller molecules, there is ………………… chance of a reaction so the entropy is …………….. .
Nothing, low.
More, higher.
State the seond law of thermodynamics.
The entropy of a system will increase if a physical process is irreversible.
In relation to entropy and probability, there is more likely to be ……………….. than ………………..!
Disorder, order.
What equation is this?:
ΔS = k x ln (Wf / Wr)
where W is the probability of a reaction occuring and S is entropy.
The Boltzmann equation.
k is the Boltzmann Constant.
(1.381 x10-323 joules/mole/deg.kelvin)
What does the Boltzmann Equation show?
That entropy is related to the probability of a reaction happening and will increase if a reaction is irreversible.
Does the second law of thermodynamics apply to living things? Why?
Yes. Energy is required to actively keep structures in place.
