Warrington Flashcards
What is configuration?
the fixed spatial arrangement of atoms within a molecule. Cannot be changed without breaking bonds.
What is conformation?
Flexible spatial arrangements of atoms within a molecule, without breaking bonds. The possible conformations of a protein include any structural state that can be achieved without breaking covalent bonds.
What are stereoisomers?
Things that have identical chemical formulas, but different CONFIGURATIONS.
What is an achiral molecule?
A carbon molecule that does not contain 4 different molecules bonded to a chiral carbon, can be imposed on mirror image.
How many sterioisomers can each chiral carbon produce?
One chiral carbon can have two stereoisomers, and two or more chiral carbons can have 2^N stereoisomers.
What is an enantiomer?
Stereoisomers that are mirror images of each other, and therefore cannot be super imposed on each other.
Diastereoisomers
pairs of stereoisomers that are not mirror images of each other(enantiomers)
Racemic Mixture
equimolar solution of two enantiomers
R and S Chirality Process
Assign a priority to 4 constituent groups of chiral carbon. Top priority goes to atom with highest atomic number(if same atomic number use highest atomic number attached to each of them to break tie) Hydrogen will always be 4 and pointed away from you, use this arrangement and draw a circle tracing from your number one to number 3, if the circle goes right it is R, if it goes left it is S
Stereospecificity
the ability of cells to distinguish between stereoisomers
System
constituent reactants and products, the solvent that contains them and the immediate atmosphere
Universe
system and its surroundings
Isolated System
does NOT exchange energy or matter with its surroundings
Closed System
DOES exchange energy but NOT matter
Open System
exchanges BOTH energy and matter with surroundings(living organism is open system)
First Law of Thermodynamics
In any physical or chemical change, the total amount of energy in the universe remains constant, although the form of energy may change.
Second Law of Thermodynamics
The tendency in nature is toward ever greater disorder in the universe; the total entropy of the universe is continually increasing. (entropy is a measure of randomness or disorder, change in randomness is expressed as ΔS. ΔS has a positive value when randomness increases.
Examples of Entropy
Whenever a chemical reaction results in an increase in the number of molecules, or when a solid is converted to a liquid or liquid to gas, we say entropy increases. Amino acids out of sequence floating around are high entropy low information, when put in proper sequences, they are low entropy high information.
Gibbs Free Energy
ΔG=ΔH-TΔS (change in free energy is equal to the change in enthalpy minus Temperature(Kelvin) multiplied by change in entropy). Change in ΔG will determine if a reaction takes place. ΔG>0 means non spontaneous reaction, requires input of energy, is endergonic reaction. ΔG<0 means spontaneous reaction with release of energy, called exergonic reaction. ΔG=0 reaction at equilibrium.
Enthalpy
reflects number and kind of bonds(typically a measure of relative energy of a system)
ΔH changes
Negative number=exothermic(heat release)
Positive number=endothermic(heat absorbed/needed)
ΔS changes
Negative number means entropy decreases, system becomes less random.
Positive number=entropy increases, system becomes more random.
ΔG Summary
Think of ΔG graphs like a slide going from products to reactants, you cant slide uphill so reaction is not spontaneous when products higher relative to reactants, will require input of energy(endergonic). When reactants are relatively higher than products, it will proceed spontaneously and give off energy (exergonic)
Enzymes
Enzymes lower the activation energy and increase reaction rate. Enzymes are not used up in the reaction. Enzymes generally bind to one reactant, but can also bind two separate reactants closely together to increase the chances of a reaction occurring.
