Thermodynamics Flashcards
What is the first law of thermodynamics?
Law of conservation of energy
What is the second law of thermodynamics?
Entropy
What is Gibbs Free Energy?
Energy available to do useful work
What is Enthalpy (H)?
A measure of heat energy that reflects bond formation and breakages
If delta H is greater than 0, the reaction is ___?
Endothermic - heat is absorbed
If delta H is less than 0, the reaction is ___?
Exothermic - heat is released
What is the equation for free energy change during a chemical reaction?
delta G = delta H - T x delta S
When entropy increases, what is the sign for S?
Postitive
If the change is enthalpy is negative, is heat released or absorbed?
Released
When is T negative?
Never. It is in Kelvin
In bioenergetics which reaction is thermodynamically favorable, endergonis or exergonic?
Exergonic
What do endergonic reactions require?
An input of energy (+delta G)
Which reaction releases energy, endergonic or exergonic?
Exergonic (-delta G)
How can a thermodynamically unfavorable process be driven forward?
By coupling endergonic and exergonic reactions, often by coupling to the hydrolysis of ATP
What is the equilibrium constant?
A ration of products/reactants
On what does the reaction rate depend?
Activation energy
Overall free energy change is ___.
Additive
Overall equilibrium constant is ___.
Multiplicative
How much ATP is in the body?
100g
How much ATP does a resting human consume per day?
40 kg
How fast is ATP typically consumed?
Usualy within 1 minute of formation
Catabolic processes are ___ and ___
Exergonic
Oxidative
Anabolic processes are ___ and ___.
Endergonic
Reductive
Catabolic processes, being oxidative, produce what?
NADH/NADPH
Anabolic processes are reductive, meaning they use what?
NADH/NADPH
Oxidation is ___
Loss of electrons
Reduction is ___
Gain of electrons
What drives redox reactions?
Electron transfer
What are the 4 ways that electrons are transferred?
- Directly as electrons
- As hydrogen atoms
- As a hydride ion
- Direct combination with oxygen
What is the oxidation state of nitrous oxide? (N2O)
+1
What is the oxidation state of nitric oxide?
+2
Biological redox is largely based on which amino acid?
Cysteine
What are the most common biological redox partners?
NADH
FADH2
Enzymes that catalyze biological redox reactions are called what?
Dehydrogenases
What is an oxidizing agent?
An electron accepting molecule
What is a reducing agent?
An electron donating molecule
In a redox couple, which molecule has the greater reduction potential and will therefore get reduced?
The molecule with the more positive E value
Are NADH and NADPH protein bound?
No - they are freely soluble
