Bioenergetics Flashcards
What is metabolism?
A co-ordinated set of chemical reactions catalysed by enzymes
What do energetics dictate?
The rates & equilibrium positions of reactions
What does a closed system eventually reach?
Equilibrium
What does an open system eventually reach?
A steady state
What is the 1st law of thermodynamics?
The law of conservation of energy.
Total amount of energy in a system stays the same but can be found in different forms.
What is enthalpy?
The heat absorbed during a reaction at constant pressure
What affect does adding heat (Q) or work (W) to a closed system have?
Increases enthalpy/total energy of system
What is the total change in enthalpy from initial to final state independent of?
The path taken
What is a reaction that gives out heat called?
What will the enthalpy of this reaction be?
Exothermic
Negative
What is a reaction that takes up heat called?
Endothermic
What is assumed during thermochemistry?
How is this different to biological reactions?
The reaction is at constant pressure and does no work
Some can convert chemical reactions to work
What are some examples of work being carried out in biological systems?
Mechanical work performed by muscles
Electrical work required to transmit nerve impulses
Chemical work to synthesise molecules (anabolism)
What is the 2nd law of thermodynamics?
When energy is converted from 1 form to another, some of the energy becomes unavailable to do work
E.g. heat energy dissipated into the environment cannot be re-used
What is entropy?
A measure of the disorder or unavailable energy in a system
What alone can drive reaction?
Entropy