16/11/18
Dr Rosalind Hannen
Energy and The Creation of Order
Bioenergetics – like thermodynamics e.g. entropy and enthalpy
• Difference between living and abiotic
• Open system – energy can be added or lost to surrounding
• Closed system – energy remains in a system
1st Law of Thermodynamics – conservation of energy
2nd Law of Thermodynamics – entropy must increase
Cells tend toward order, not the other way around so therefore need energy
However, they still obey these rules as heat loss creates disorder in the surroundings
• This can help maintain temperature so very useful
• Can sacrifice energy to create order
Chemical Bond Energy
• Organisms need a constant supply
• Digestion and oxidation uses proteins, lipids and
carbohydrates
Enzymes
• Even when ΔG is negative, energy is needed to
overcome activation energy
• Enzymes lower activation energy
EA
• Usually very high in biochemistry
o This prevents the reaction from happening spontaneously
• States –
o Metastable – without activation energy
o Active state – when substrate is bound to the enzyme
• Consensus – sequence specific to enzyme and substrate
Dr Rosalind Hannen
Energy and The Creation of Order
Bioenergetics – like thermodynamics e.g. entropy and enthalpy
• Difference between living and abiotic
• Open system – energy can be added or lost to surrounding
• Closed system – energy remains in a system
1st Law of Thermodynamics – conservation of energy
2nd Law of Thermodynamics – entropy must increase
Cells tend toward order, not the other way around so therefore need energy
However, they still obey these rules as heat loss creates disorder in the surroundings
• This can help maintain temperature so very useful
• Can sacrifice energy to create order
Chemical Bond Energy
• Organisms need a constant supply
• Digestion and oxidation uses proteins, lipids and
carbohydrates
Enzymes
• Even when ΔG is negative, energy is needed to
overcome activation energy
• Enzymes lower activation energy
EA
• Usually very high in biochemistry
o This prevents the reaction from happening spontaneously
• States –
o Metastable – without activation energy
o Active state – when substrate is bound to the enzyme
• Consensus – sequence specific to enzyme and substrate
