Fechar
Concepts to understand
Definition of kinetics
1 a: a branch of science that deals with the effects of forces upon the motions of material bodies or with changes in a physical or chemical system
b: the rate of ___ in such a system
2: the mechanism by which a physical or chemical change is effected
Chemical kinetics studies reaction ___:
-->Mathematical description based on the reaction model
-->What affects the rates: T, pH, enzymes, spatial restrictions, ...
Zero Reaction
The biochemical reaction may be of zero-order when enzyme-catalyzed
max
This happens when the enzyme (E)
is saturated by the substrate (S).
Concentration of S exceeds that of E
[S] >> [E}
Mon-molecular FIRST ORDER Reaction
A --> B (can be reversible)
k = rate (depends on multiple factors such as temperature)
rate = ___
reaction rate units = ___
1 st order reaction:
Biochemical reaction may be of 1st order when enzyme-catalyzed
If this case [S] __ [E].
Second-Order bimolecular reaction
A + B --> C + D
rate or V = ____
Second-Order bimolecular reaction
& Equilibrium Concept
Equilibrium when: forward rate = ___ rate
k1[A][B] = k-1[C][D]
The ratio of product to reactant concentrations is constant:
Keq = concentration of products / concentration of reactants (k1 / k-1)
so it would look like: ____ / ____
when keq >> 1 then rxn strongly favors ___
when keq << 1 then rxn strongly favors ____
Thermodynamics is the flow of __
0th Law of thermodynamics =
states that if two thermodynamic systems are each in thermal equilibrium with a third one, then they are in thermal equilibrium with ___ ___
First Law of Thermodynamics = The law of Conversation of Energy
The total amount of energy in the Universe remains
Energy is neither created nor destroyed, it just ___ its form
• Conservation of mass in chemistry is a special case of the law, assuming no nuclear reactions occur.
2nd Law of Thermodynamics
Multiple equivalent definitions have been proposed by scientists:
-Heat does not transfer from cold systems to hot systems
• No work can be done at a ___ temperature
• Total amount of entropy (S) of the universe always ____
What is Entropy?
defined as a measure of the system ____
3rd Law of Thermodynamics
If an object reaches the absolute zero temperature (0K = -273.15 degrees C = -459.67 degrees F), its atoms will stop moving.
T(K) = T(C) + ___
Gibbs free energy
G = __ - __
H — enthalpy, a heat function at constant pressure (p=const.)
Since most of the biochemical reactions are isobaric, ΔH = ΔHeat
S — Entropy
T — Temperature (K)
ΔH < 0 = rxn is ___
ΔH > 0 = rxn is ___
G = H-TS
Reaction will proceed forward if G is reduced ΔG __ 0
If ΔG < 0 then ΔH -TΔS must be __ 0
A non-spontaneous rxn can still proceed if ___ to another reaction providing that overall ΔG < 0
(the reaction can be entropy driven)
Reaction will proceed until it reaches ___
If ΔG = 0
Then ΔH = TΔS
If the transition state has higher energy compared to the reactants,
additional activation energy, Ea, is required
-Need to __ the activation energy
Two ways to speed up a reaction:
1. Increase ___ (may destroy your reactants)
2. Use ___ (bio-catalysts)
Equivalent to:
1. Produces more 'hot' molecules
2. ___ activation energy, 3D coordination, longer time
To find Keq:
Given a concentration of either the reactant or product
To find concentrations given Keq:
You can find concentration of [A], [B], [C], [D]
