Chapter 3: Biochem Basics Flashcards
What are the two forms of energy in chemistry?
- Kinetic energy
- Potential energy
What is the equation for Gibbs free energy?
Delta G = delta H - T delta S (T represents temp & H represents enthalpy)
What is the equation for enthalpy?
Delta H = delta E + PdeltaV (E represents the bond energy of products in the system & P is pressure, & V is volume)
Delta G increases when delta H _________ & decreasing with increasing entropy
Increases
Delta G is spontaneous when its ________ & nonspontaneous when its __________
Negative, positive
The value of delta G depends on the _____________ of the reactants & products
concentration
What is the equation for delta G related to equilibrium constant
delta G = -RT lnKeq
If we wanted to calculate the delta G for a reaction in the body what is the equation?
delta G = delta G prime + RT ln Q (Q uses the actual concentration of the products & reactants not the equilibriums)
All reactions proceed through a ___________________ that is unstable & takes a lot of energy to produce
transition state (TS
The __________________ is the energy required to produce the transition state
Activation energy (Ea)
A catalyst lowers the Ea of a reaction ___________ changing the delta G
Without
Oxidation is a ________ of electrons & Reductions are a _______ of electrons
Loss, Gain
How do you recognize oxidation reactions?
- Gain of oxygen atoms
- Loss of hydrogen atoms
- Loss of electrons
How do you recognize reduction reactions?
- Loss of oxygen atoms
- Gain of hydrogen atoms
- Gain of electrons
What is the Bronsted -Lowry definition of acids & bases?
Acids are proton (H+) donor & bases are proton (H+) acceptors
What is the lewis acid & base definition?
Acids are electron-pair acceptors & bases are electron pair donors
The larger the Ka value the _____________ the acid & the smaller the Ka value the ____________ the acid
Stronger, weaker
The lager the Kb value the __________ the base and the smaller the Kb the _________ the base
Stronger, weaker
Amphoteric substances
Substances that can act as a base & acid
The acid with the lower pKa is the __________ acid & the base with the lower pKb is the ___________ base
Stronger
Buffer
Is a solution that resist changing pH when small amount of acid or base is added
The buffer system for our blood plasma is the ____________
Bicarbonate system
Gibbs free energy is the amount of energy in a reaction available to do ___________ work
Chemical
If delta G equal 0 means what
Its at equilibrium
_________ is the study of how quickly a reaction occurs but its does not determine whether or not a reaction will occur
Kinetics
A __________ lowers the energy of the transition state, which decreases the Ea and increases the amount of product formed per unit of time
catalyst
When a reaction is favorable (or spontaneous) means it will occur in the ___________ direction
Forward
When a reaction is unfavorable (or nonspontaneous) means it will occur in the ___________ direction
Reverse
In a reaction if there is a compound that has been oxidized or reduce then it means its a __________ pair
redox
When an molecule is in its standard state (ex. O2) its oxidation state is __________ but when its in a compound its oxidation will be positive or negative
zero
When dealing with the Bicarbonate buffer system when you hold your breath what happens?
When you hold your breath the CO2 concentration in your blood increase which will increase H2CO3 (carbonic acid) which will decrease the pH
Kinetic energy comes from __________ of molecules
Movement
Potential energy comes from energy stored in _________ bonds
Chemmical
1st law of thermodynamics
States that the energy of the universe is constant (when energy of the system decrease the energy of the surroundings increase)
2nd law of thermodynamics
States that the disorder (entropy) of the universe tends to increase (spontaneous reactants tend to increase the disorder of the universe)
Favorable reactions have a _________ delta G
Negative
Reactions with a negative delta G are _____________ & reactions with a positive delta G are ________
Exergonic (energy leaves the system), endergonic (energy is added)
The sign of thermodynamic quantities depends on the point of view of the _________
System (not the surroundings)
A negative delta G means that the system will go to a _________ free energy state ( & a system always moves in the direction of the lowest free energy )
Lower
A ____________ Keq means that more products are present at equilibrium & equilibrium tends to move toward the lowest energy state so when Keq is ______ products have lower free energy than reactants
Large
_____ is irrelevant to free energy of products & reactants only Keq is
Q
At equilibrium how is Q related
to Keq?
Its equal (Q=Keq) so forward reaction rate = reverse reaction rate & the net concentrations of reactants & products don’t change
When delta G = 0 what does it mean for the reaction
Its at equilibrium so it occurs at the same rate for the forward & reverse reactions
Enzymes only have a kinetic role not a thermodynamic so it will only affect the ______ not concentration of products & reactants
rate
When oxidation occurs so does a ___________ reaction an
Reduction (redox pair)
What is the bicarbonate buffer system
- H2CO3 ———-> H+ CO3
- CO2 +H2O —–> H2CO3
A positive delta S means what?
Increase in disorder
A negative delta S means what?
An increase in order (but entropy is favorable when its an increase in disorder)
When delta G is negative but delta H is positive what can that tell you?
That its working against the reaction since a positive delta H means an input of energy but a negative delta G means its spontaneous & happens on its own
A more negative delta G means what?
An increase in spontaniety
A negative delta H means what & a positive delta H means what>?
Positive means its endothermic (input of energy due to bonds forming) & negative means it’s exothermic (energy released due to bonds breaking which would increase the disorder (positive delta S)
1st law of thermodynamics
The energy of the universe is constant (where energy of the system decrease the energy of the surroundings increase)
2nd law of thermodynamics
The entropy tends to increase
The value of delta G depends on _______________ of reactants & products
Concentrations
_____ is the concentration at any point & k is the concentration at equilibrium
Q
Even though a reaction may be spontaneous it will be slow due to what?
A large activation energy
When one atom is reduced another must be __________
Oxidized (redox pair)
Any anion or any neutral species with a lone pair of electrons can function as a _______
Base
Hassel Balch equation
pH= pka + log [A-]/[HA]
