Biochem Basics Flashcards
Thermodynamics
The study of energetics of chemical reactions
Kinetic energy
Movement of molecules
Potential energy
Energy stored in chemical bonds
First Law of Thermodynamics (alt. name)
The Law of Conservation of Energy
First Law of Thermodynamics (def.)
Energy of the universe is constant. This implies that when the energy go a system decreases, the energy of the surroundings/rest of the universe must increase, or vice versa
Second Law of Thermodynamics (def.)
The disorder, or entropy, of the universe tends to increase; spontaneous reactions tend to increase the disorder in the universe
Entropy Symbol/Letter
S
Change in Entropy Denotation
Delta S
Entropy Equation
Delta S = S (final) - S (initial)
If the Delta S of a system is negative, has the disorder of that system increased or decreased?
If Delta S is negative, then the system has lost entropy, which means disorder has decreased
Gibbs free energy Equation
Delta G = Delta H - T(Delta S)
What does Delta H stand for?
Enthalpy
Enthalpy Equation
Delta H = Delta E + P(Delta V)
E represents the bond energy of products or reactants in a system
Delta G relationship to Delta H
Delta G increases with increasing enthalpy (Delta H)
Directly proportional
Delta G relationship with Delta S
Delta G decreases with increasing entropy (Delta S)
Indirectly proportional
What kind of Delta G do favorable reactions have?
Delta G < 0
This is a decrease in free energy, which makes reactions more favorable because Gibb’s Free Energy Equation tells us that increasing entropy (S) makes a reaction more favorable
Delta G in Spontaneous reactions
Delta G < 0 (negative)
Exergonic (def.)
Energy exits the system; spontaneous
Delta G in Exergonic Reactions
Delta G < 0 (negative)
Delta G in non spontaneous Reactions
Delta G > 0 (positive)
Endergonic (def.)
Endergonic reactions only occur if energy is added to the system; energy input is required; nonspontaneous
Delta G in Endergonic reactions
Delta G > 0 (positive)
Exothermic (def.)
Heat is liberated/ released from the system
Most metabolic reactions in the body are exothermic or endothermic?
Exothermic
Delta H in Exothermic reactions
Delta H < 0 (negative)
Endothermic (def.)
Heat is added/ input to the system
Delta H in Endothermic reactions
Delta H > 0 (positive)
What free energy state does the system go into with a negative Delta G? (Higher or Lower)
Lower - Think of a spinning top slowing down and moving towards a lower energy state; negative delta G means energy is leaving the system, and therefore there is lower free energy
