Review 2 Flashcards
Titration Indicators
- Methylated pH - 4.4-6.2 (~4-6)
- Bromothymol blue - 6.0-7.6 (~6-8)
- Phenolphthalein - 8.2-10 (~8-10)
Formula for pI
pI = (pKa1 + pKa2)/2
2 Ways to make a buffer
- Adding weak acid and weak base in equal amounts
2. Partially titrating weak acid with half strong base or partially titrating weak base with half strong acid
Bronsted-Lowry Acid and Base
BA - Proton donor
BB - Proton acceptor
Lewis Acid and Base
LA - Electron pair acceptor
LB - Electron pair donor
Amphoteric
Acid and Base consecutive properties
Amphipathic
Hydrophobic and hydrophilic properties
Strong Acids
HNO3, HCl, H2SO4, HI, HBr, and HClO4
Strong Bases
NaOH, KOH, Ca(OH)2, Mg(OH)2
Acidity with Ka and pKa
Lower the pKa, the higher the acidity. The higher the Ka, the higher the acidity
Basicity with Kb and pKb
Lower the pKb, the higher the basicity. The higher the Kb, the higher the basicity
Relationship between Ka and Kb
Ka*Kb = Kw
pKa + pKb = 14
Henderson-Hasselbach Equation
pH = pKa + Log[A-]/[HA]
Arrhenius Acid
Yields H3O+ when added to H2O
Arrhenius base
Yields OH- when added to H2O
Carboxylic acids/Carboxylates
RCOOH/RCOO-
Alkyl ammoniums/alkylamines
RNH3+/RNH2
Phenols/Phenoxides
C6H5OH/C6H5O-
Carbonic acid/Bicarbonate
H2CO3/HCO3-
Phosphoric acid/dihydrogen phosphate
HPO4/H2PO4
Non-metal hydroxides Type of Acid
Lewis Acids
Non-metal Oxides type of Acid
Bronsted-Lowry Acids
Metal hydroxides Type of Base
Lewis Base
Metal Oxides type of Base
Bronsted-Lowry Base
Polyprotic Acids
The first proton is more acidic than the second one removed pKa1 < pKa2:
1. Carbonic acid (H2CO3)
- Sulfuric Acid (H2SO4)
- Phosphoric acid (H3PO4)
Water and measurement of strong acid strength
Water cannot be used as a solvent since it goes to completion as it protonates fully from the strong acid
SOLUTION: Use a base weaker than the water as the standard solvent
Water and measurement of weak acid strength
Weak acids are relatively stable because they do not easily deprotonate because it is their stable form.
SOLUTION: Water can be used here
Halides and Electronegativity and Acidity
Halides size is not important. Electronegativity is more important
RNA Virus Peculiarity
- They store genetic information as RNA
- They can replicate their RNA
- They can use their RNA as mRNA for translation
Epigenetics and Method
Heritable changes in traits (DNA) without changing the sequence of DNA e.g:
1. DNA methylation
- Histone modification
Another name of Peptide Bond
Nucleophilic addition-elimination Reaction
Methods for breaking peptide bonds
- Acid hydrolysis (strong acids with heat)
2. Proteolysis (uses protease)
Acid Hydrolysis vs. Proteolysis
Former is non-specific and latter is specific
Peculiarity of Histidine, Proline, Glycine, and Cysteine
Histidine - pKa 6.5~7
Proline - R ring
Glycine - H instead of R and achiral
Cysteine - Can be reduced/oxidized (disulfide bonds)
Cell and Redox Reactions
Extracellular = Oxidizing environment and Intracellular = Reducing environment
Trick for Naming Land D of Amino acids with Fischer Projections
Look at the location of the amino group on the horizontal line
Isoelectric point (pI) and Buffer
- Point along the pH scale in which it exists in its neutral form
- Personal thought is to use pI to predict the next pH change I think neutrality
Factors on Protein Folding
- Temperature - (Destroys 2, 3, and 4) but not 1 (think of eggs
- pH - breaks ionic bonds
- Chemicals - break H-bonds
- Enzymes - Break covalent bonds (1)
Folding Levels
- 1’ - Sequence (peptide bonds)
- 2’ - Backbone interactions (H-bonds)
- 3’ Distant interactions (VD, H, Hydrophobic, Disulfide bonds)
- 4’ - Subunit Same as 3’
Ribose, Glucose, Fructose, Galactose, and Mannose Trick
Ribose - All Right Glucose - Left Fuck Frustose - Ketose Mannose - Left Gun Galactose - C4 Epimer of glucose
Lactose, Maltose, and Sucrose
- Lactose - Galactose and Glucose (Reducing sugar becasue of hemiacetal)
- Maltose - Glucose * 2 (Reducing sugar like lactose)
- Sucrose - Glucose and Fructose (Non-reducing sugar because of acetal)
Branched Polysaccharide of Glucose
Glucose and Amylopectin
How do the DNA strands know to orient themselves?
- -ve charges of Phosphate are moving away from each other (repulsion)
- N-bases want to be close because of H-bonds
Methods of Enzyme Works
- Acid/Base Catalysis - H+
- Covalent modification - e-
- Electrostatic Catalysis - + and -
- Proximity and Orientation Effects
Types of Enzymes
- Transferase
- Ligase
- Oxidoreductase
- Isomerase
- Hydrolase
- Lyase - Does not use redox or water to break bonds. Forms rings or double bonds
Co-enzymes
- They are organic carrier molecules (NAD+, acetyl-coA)
Co-factors
Help enzyme with catalysis and actually take part in catalysis e.g Magnesium with DNA (+ and -)
Two particular environments that alter Enzyme function
pH and Temperature
Assumptions made in Enzyme Kinetics
- Solutions are behaving ideally
E + S ES E + P - Constants are indeed constant
[E] - Protein synthesis and degradation
K - Environmental factors - S -> P without enzyme is negligible
Michaelis-Menton Equation
V0 = Vmax[S]/(Km+[S])
V0
Vmax/2
Catalytic Efficiency
Kcat/Km
Kcat
Turnover number - How many can it make into products in one sec
Vmax/Et