BIOCHEM CH.3 PART 1 Flashcards
What is the first law of thermo?
Energy of the universe is constant; cannot be created or destroyed
What is another term used to explain the first law of thermo?
Law of conservation of energy
What is the second law of thermo?
Universe tends to increase towards entropy
What is the symbol for entropy?
S
What is the equation for Gibbs free energy?
ΔG = ΔH - TΔS
What does ΔH symbolize?
Enthalpy
What is the equation of enthalpy?
ΔH = ΔE + PΔV
In the enthalpy equation ΔH = ΔE + PΔV what does E represent?
Bond energy of products or reactions in a system
In the enthalpy equation ΔH = ΔE + PΔV what does P represent?
Pressure
In the enthalpy equation ΔH = ΔE + PΔV what does V represent?
Volume
Since all cellular reactions take place in a liquid phase, how is H related to E in a call?
H = E since the change in volume is negligible ΔV= 0 (no change)
Based on increasing and decreasing, how does ΔG relate to ΔH? What about entropy (S)?
ΔG increases with increasing ΔH (bond energy)
Decreases with increasing entropy
Favorable reactions has a ΔG that is….?
< 0
How does ΔG need to be for the reaction to be favorable? Or unfavorable?
ΔG negative, ΔG positive
What does it mean when ΔG is negative in a reaction?
Energy to spare
Reaction with a negative ΔG are said to be…?
Exergonic
Reaction with a positive ΔG are said to be…?
Endergonic
Endergonic reactions only occur if energy is….?
Added
Reactions with a negative ΔH are said to be…?
Exothermic
Reactions with a positive ΔH are said to be…?
Endothermic
What do endothermic reactions require, based on ΔH?
An input of heat
How is a standard free energy change calculated ΔG°?
With all reactants and products at 1 M concentration
What is the denotation of ΔG°’?
1 M concentration for all solutes except H+ and a pH of 7
What is the equation of ΔG°’?
ΔG°’ = -RT(In)K’eq
ΔG°’ = -RT(In)K’eq, please describe each variable?
R = gas constant K'eq = ratio of products to reactants at equilibrium
How do you calculate K’eq?
K’eq = [C]eq[D]eq / [A]eq[B]eq
What is the equation for ΔG for a reaction in the body?
ΔG = ΔG°’ + RT(In)Q
ΔG = ΔG°’ + RT(In)Q, what is Q?
Q = [C][D] / [A][B]
What is different between Q and K’eq based on the Gibbs free equations?
Q uses the actual concentrations
How would we be able to recreate the laboratory standard initial set-up for ΔG = ΔG°’ + RT(In)Q?
Q =1 so InQ = 0 and then ΔG = ΔG°’
What is the definition of equilibrium?
The point where the rate of reaction forward equals the rate of reaction in the reverse direction
What are the two factors that determine whether a reaction will occur spontaneously in the cell?
- Intrinsic properties of the reactants and products (Keq)
12. Concentration of reactants and products (RTInQ)
What will thermodynamic tell you about a reaction?
Where a system starts and finishes but nothing about the path travelled to get there
What is the name of the energy required to produce a transition state?
Activation energy (Ea)
What does a catalyst do in chemical kinetics?
Lowers the Ea of a reaction w/o changing the ΔG?
How does the catalyst lower the Ea?
Stabilizing the transition state, making it less thermo unfavored
How does catalyst affect free Gibbs energy?
They do not affect ΔG
What type of energy metabolism are humans?
Chemoheterotrophs
What is oxidation? What is reduction?
Oxidation: Loss of electrons
Reduction: Gain of electrons
What are the three ways to recognize oxidation reactions?
- Gain of oxygen atoms
- Loss of hydrogen atoms
- Loss of electron
What are the three ways to recognize reduction reactions?
- Loss of oxygen atoms
- Gain of hydrogen atoms
- Gain of electrons
What does redox pair mean?
When one atoms gets reduced, another one must be oxidized
What is the way we extract energy from glucose?
Oxidative catabolism
What is the Bronsted-lowry acids and bases definition?
Acids are proton DONORS
Bases are proton ACCEPTORS
What is the lewis definition of acids and bases?
Lewis acids are electron-pair acceptors
Lewis bases are electron-pair donors
What is a conjugate base?
When an acid donates a H+, its remaining structure is called this
What is a conjugate acid?
When a base accepts a H+, its remaining structure is called this
The strength of an acid (Ka) is related to what?
Directly related to how much the products are favored over the reactants
What is Ka?
Acid-ionization (acid-dissociation) constant of the acid (HA)
What is Kb?
Base-ionization (base-dissociation) constant
What is polyprotic?
More than one proton to donate
What is amphoteric?
A substance that can act as either a acid or a base
What type of molecules, based on acids and bases, are always amphoteric?
The conjugate base of a weak polyprotic acid
What is the equation of pH?
pH = -log[H+]
What does the pH formula imply?
{H+] = 10-pH
What is the concentration of H+ in pure water and what’s its pH?
[H+] = 10^-7, the pH of water is 7
What temperature defines a pH at neutral solution?
25 degrees celsius
How to calculate the pKa and pKb?
-logKa or -logKb
From the pKa value, how do we know the strength of the acid?
Lower pKa value, stronger acid
From the pKb value, how do we know the strength of the base?
Lower pKa value, stronger base
What is the most important buffer system in our blood plasma?
Bicarbonate buffer system
What molecules are included in the bicarbonate buffer system?
Carbonic acid (H2CO3) and its conjugate base (HCO3-)
What are the two reactions of the bicarbonate buffer system?
- H2CO3 -> H+ + HCO3-
2. CO2 + H2O -> H2CO3
What happens when H+ is high due to lactic acid production?
Reaction 1 H2Co3 -> H+ + HCO3 shifts to the left to reduce amount of free H+
