Thermodynamics Flashcards
What are thermodynamics?
Free energy, activation energy, energy coupling, metabolic control via enzymes & substrate reactions
Describe cell metabolism
Food -> ATP -> Heat/Excretion
Where is energy derived from?
Fat, protein, carbs
What purpose do biochemical reactions complete?
Generate heat (60% body heat) and generate chemical energy (40%) to be used
What is free energy?
Spontaneous reactions liberate energy, some of this energy can be used for other purposes and is called free energy
Where does free energy come from?
Chemical bonds of nutrients released by combustion & oxidation
Where is free energy used?
Inside the cell (constant pressure & temperature)
What is the 1st law of thermodynamics?
Energy can be neither created nor destroyed
How to calculate free energy?
Energy(G) of products - Greactants = free energy
Why is free energy important in metabolism
Free energy estimates the likelihood of a metabolic step to occur
Explain positive, negative and equilibiurm free energy
Free energy is 0 at equilibrium, positive free energy means that a reaction requires energy input (non-spontaneous, endothermic), negative free energy means that the reaction produces energy (spontaneous, exothermic)
What is the difference between standard free energy change and non-standard free energy change?
Non-standard free energy (^G) is constant for a certain reaction. Standard free energy change (^G0) allows for comparison of energy change in different reactions
^G = ^G0 + 0.616Ln[B]/[A]
What is the importance of the difference between ^G and ^G0?
The concentration of rectants influences the free energy change and a reaction’s direction
What is the rate of reaction dependent/independent on?
Independent from magnitude of ^G, dependent on energy of activation
Do all reactions require activation energy?
Yes, even spontaneous
