Module 3: Chemical Reactions Flashcards
Acid/Base Reaction
- transfer of protons from one species to another
- most common
- change in charge (either charges to neutral or neutral to charged)
Substitution Reaction
switching one group for another
*usually see swinging arrow into and out of reaction
Types: Nucleophilic, aromatic, acyl
Nucleophilic Substitution
addition of a nucleophile to an electrophile
Aromatic Substitution
sub of a Hydrogen on an aromatic ring with another group (NOT Oxygen or nitrogen <- then it would be considered REDOX)
Acyl Substitution
addition of a nucleophile to a carbonyl group (esters, amides, carboxylic acids) or sulfonate group or phosphate group.
Nucleophile
- electron rich (provide e- to create new bonds)
- Nucleus loving <3
- anions (look for neg charge), heteroatoms w/ lone pair, alkenes, alkynes
Electrophile
- electron poor species
- electron loving <3
(carbocations, carbonyl group, alkenes, alkynes)
*Hydrogen can never be the electrophile.
Catalyst
- help increase the rate at which the reaction occurs
All biochem reactions utilize enzymes and cofactors as catalysts
Catalysis
- increase reaction rate
- takes alternate pathway
- Catalysts do NOT appear in product
- Catalysts are NOT consumed (recycled for something else) - if they were, we would burn too much energy.
Krebs cycle - glycolysis
Elimination Reaction
- removing a group completely from the molecule
look for a double or triple bonds created!!!
*usually an arrow going away from reaction
Addition Reaction
- adding a group to a molecule (usually start with a ketone or aldehyde)
*usually arrow coming into reaction
REDOX Reactions
changing the oxidation state of a group on a molecule
1. Oxidation - increase bonds to O or N, or decrease in bonds to H
2. Reduction - decrease in bonds to O or N, or increase in bonds to H
*usually see a half circle arrow swinging through reaction (NAD+ to NADH, etc)
Isomerization Reaction
- rearrangement of groups within the same molecule
- Least common
Enzymes
- globular proteins end in -ase.
- main catalysts used in reactions
*helps decrease activation energy required for a chemical reaction - makes Delta G negative (Exothermic)
How are enzymes classified?
- Efficiency (natural better than chemical/lab catalysts)
- Specificity
- Regulation
What is
Delta G?
- Gibbs Free energy - want to be negative
- a measure of whether or not a chemical process will or will not work.
- based on Delta H (enthalpy) and Delta S (entropy) and temperature
Delta H
Enthalpy - measure of energy difference btwn products and reactants (endothermic & exothermic)
We want exothermic - we want to produce energy
*we do not want a system that requires energy.
Delta S
entropy = degree of disorder
enzymes create more disorder via confirmational change - we want this!
Cofactors
- Non-protein component required to allow an enzyme to perform its role!
- bind with enzyme
*REDOX need a co-factor.
Types of Cofactors
Inorganic
Mg, Zn, Cu, Fe, Mn, Ni, Mb (minerals)
Types of Cofactors
Organic
vitamin derivitives
(usually B vitamins)
Enzyme Classes
- Transferase (sub)
- Hydrolase (sub - using water)
- Oxidoreductase (redox)
- Lyase (elimination)
- Ligase (addition)
- Isomerases (isomerization)
Transferase Enzyme
- Transfer functional groups
- Substitution reactions (*acyl, nuclephilic, aromatic)
*acyl usually uses hydrolase (look for use of H2O)
Hydrolase Enzyme
- breaks bonds using water!!!
- usually substitution reactions (mostly acyl - ester to a carboxylic acid)
*saponification (hydrolysis of fats)
Oxidoreductase Enzyme & examples
- catalyze REDOX reactions
*CYP450s, MAOs, dehydrogenase (alcohol), H2O2
Ligase Enzymes
- join two molecules together
- addition reactions (“The Catch All!”)
Lyase Enzyme
- breaks chemical bonds (Elimination - NOT REDOX)
*ATP > cAMP
Isomerase Enzyme
- promote structrual shifts in the substrate
ID the reactions
*ignore the “addition” :)
