Metabolism - Lecture Twenty-Seven Flashcards
Overview of Metabolism: Bioenergetics
Fuel molecules
Nutrients such as glucose, fats and protein
Why do we have fuel molecule intake?
To do our cellular work through ATP energy
What does the ∆G of a reaction tell us?
The relative abundance of the substrates and products and the energy stored in the chemical bonds of the products and substrates
∆G < 0 for A ➝ B
The reaction is spontaneous, energy is released and is energetically favourable
∆G = 0 for A ➝ B
The reaction is at equilibrium, and there is no change in energy
∆G > 0 for A ➝ B
The reaction is not spontaneous, energy is required and is energetically unfavourable
∆G
Specific conditions
∆G˚
Standard conditions - all reactants 1M
∆G˚’
At pH 7
When is ATP hydrolysis energetically favourable?
At ∆G˚’ = -30kJ/mol
When is ATP synthesis energetically unfavourable?
ΔG˚’ = 30 kJ/mol
Why do enzymes often couple reactions?
To drive necessary unfavourable reactions?
Two key types of reactions
Phosphorylation of ADP to ATP and redox reactions
Coenzymes NAD and FAD
Interact with various enzymes to accept and donate reducing equivalents (hydrogen)
What do biological redox reactions often involve?
The transfer of hydrogen atoms (includes an electron)
