Thermodynamics Flashcards
What is the first law of thermodynamics
Conservation of energy: Energy remains constant; it may change from one form to another but it cant be created or destroyed.
What is the second law of thermodynamics
In all natural processes, the entropy of the universe increases. Total entropy includes both the system and surroundings
Living organisms are ____systems
open
We can ___order within ourselves but ____order in our surroundings.
create; decrease
We extract energy from nutrients via _____reactions
catabolic
We use energy for work:
motion, ionic/electrical gradients, anabolic reactions,
____processes produce simple components and increase entropy
Catabolic
____processes use simple components and decrease entropy
Anabolic
Gibbs free energy is defined in terms of:
- Enthalpy: a measure of heat energy that reflects bond formation and breakage
- Entropy (S): randomness
- Temperature (T): in K
If delta H is greater than 0=
endothermic; heat energy is absorbed
If delta H is less than 0
exothermic; heat energy is released
By convention delta S is positive when
entropy increases
By convention delta H is negative when
heat is released to the surroundings
By convention T is always
positive
Endergonic reactions require ____ of energy (positive delta G); and its thermodynamically _____
input; unfavorable
Exergonic reactions ____energy (negative delta G); and its thermodynamically ____ and _____
release; favorable and spontaneous
Endergonic reactions can be coupled to ____reactions to drive a thermodynamically unfavorable process forward, often by coupling to the hydrolysis of ____
exergonic; ATP
Equilibrium is formation of products = formation of _____
reactants
Delta G of chemical reactions is alternative of equilibrium contant:
Keq
Equilibrium constant is constant as ratio of products over
reactants
If Keq is greater than 1, then:
products is greater than reactants and the reaction goes forward
If Keq is less than 1 then:
Products is less than reactants and the reaction goes in reverse
If Keq is = 1 then:
products is equal to reactants. There is no reaction
Delta G is actual energy used for ___
analysis
Delta G with degrees is ____condition
standard; used for general comparison
Delta G with degrees and prime is used for ______standard conditions
biological
Delta G degrees and prime is equal to
-RTln Keq
Reaction rate depends on ____ energy
activation
If delta G prime and degrees is greater than 23 kj/mol or Keq is less than 10^-4 the reaction is biologically
irreversible
Overall free energy change is :
additive
Overall equilibrium constant is :
multiplicative
RT =
2.478 kJ/mole
Delta G prime and degrees is equal to
-RTlnKeq
If we remove product as it is formed, then product will be low and overall delta G can be be ____even if Delta G prime with degrees is greater than 0
negative
When Keq is greater than 1:
Delta G prime +degrees is negative and the reaction proceeds forward
When Keq is 1:
Delta G prime +degrees is 0 and the reaction is at equilibrium
When Keq is less than 1
Delta G prime + degrees is positive and the reaction proceeds in reverse
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
Usually within 1 minute of formation
How does ATP store energy
- charge repulsion relieved when hydrolized
- resonance stabilization of Pi
- Ionization of ADP
- Stabilization of ADP by Mg2+ chelation
- Maintain low ATP concentration
What is PEP
member of glycolytic pathway used by bacteria as energy source to conserve ATP
Catabolic processes are ____ and _____
exergonic (produce energy) and oxidative (produce NADH/NADPH)
Anabolic processes are _____ and _____
endergonic (require energy) and reductive ( use NADH/NADPH)
Oxidation is ____of electrons
loss
Reduction is ____of electrons
gain
Redox reactions are driven by
electron transfer
Electrons are transferred by 4 methods:
- directly as electrons
- as H atoms
- as a hydride ion
- direct combination with oxygen
___ _____ is commonly used to designate a single electron equivalent participating in an oxidation-reduction reaction regardless of which of the four is the electron source.
Reducing equivalent
What is nitric oxide (NO)
A gaseous hormone
Biological redox largely based on the aa:
cysteine
Redox reactions happen in pairs called:
Redox couple
Enzymes that catalyze these reactions are called
dehydrogenases
Electron accepting molecule is the ____agent has and a ____E delta prime
oxidizing; positive
Electron donating molecule is the ____agent and has a ____E delta prime
reducing; negative
In a redox couple, the molecule with the more _____E delta prime will accept electrons and get _____; it has the greater ____ _____
positive; reduced; reduction potential
A more positive delta E prime gives you a more ___delta G prime
negative
What are some characteristics of NADH and NADPH
- Freely soluble (not protein bound)
- Transfers 2 electrons, 1 proton
- Has a fixed E delta prime
In riboflavin aka Vitamin B2:
Dela E prime is not fixed
