BCH4024 EXAM 1 REPORTED
QUESTIONS WITH CORRECT
ANSWERS
Hydrogen bonds - Answer-longer and weaker than covalent O-H bond.
Linear>bent
Number of bonds in liquid water - Answer-3.4
Number of bonds in ice - Answer-4
lifetime of hydrogen bond - Answer-1-20 picoseconds so liquid water is described as
"flickering structure"
Hydrogen bond donor - Answer-Hydrogen in N-H, O-H
Hydrogen bond acceptors - Answer-N: and O:
Rank the strength of Noncovalent interactions - Answer-1. Hydrophobic interactions
2. Pi Stacking
3. Van der Waals
4. Hydrogen bond
5. Electrostatic
6. Salt bridge
Amphipathic interaction - Answer-both hydrophilic and hydrophobic
Ion water product - Answer-Kw= [H+][OH-]= 1x10^-14 M^2
pH equation - Answer-pH = -log[H+]
Acid dissociation constant - Answer-Ka = K[H2O] = [H+][A-]/[HA]
pKa equation - Answer-pKa = -logKa
High Ka - Answer-acid dissociates a lot in solution, strong acid
Low pKa - Answer-strong acid
pH=pKa - Answer-[HA]=[A-]
, Henderson-Hasselbalch equation - Answer-pH = pKa + log [A-]/[HA]
Buffers - Answer-Consist of an aqueous solution of a weak acid and its conjugate base.
resist changes in pH when small amount of acid or base are added
Transcription - Answer-Creates a complementary RNA copy (mRNA) of a sequence of
DNA
Translation - Answer-mRNA is decoded by ribosome and tRNA is used to produce a
specific amino acid chain, or polypeptide, that will later fold into an active protein
Charge of amino acid - Answer-charge is dependent on pH of solution, +1,0, or -1
Isoelectric point - Answer-pI=pH average charge is 0
Isoelectric point equation - Answer-pI=(pKa1+pKa2)/2
4 different groups - Answer-chiral
at least 2 of the 4 groups the same - Answer-achiral
Alpha carbon - Answer-central carbon, chiral center
look along H-Calpha bond and read clockwise to spell CORN for L-configuration
Disulfide bonds - Answer-pairs of cysteines can oxidize to form cystine through a
disulfide bond
peptide bond formation - Answer-a molecule of water is expelled in a condensation
reaction that requires ATP
-amino acids are added to C-terminal
peptide bond structure - Answer-shorter and is not able to rotate due to double bond
character
C-N 1.32A
-coplanar
Peptide bond torsion angles - Answer-phi= Calpha-N
psi= C=O to Calpha
omega= C=O to N
Peptide bond configuations - Answer-Trans is more stable bc omega is restricted to 180
degrees. Except in proline
Polypeptide nomenclature - Answer-N-terminus on the left and C-terminus on the right.
Name AA's in order starting at N-terminus w every AA ending in -yl expect C-terminus
QUESTIONS WITH CORRECT
ANSWERS
Hydrogen bonds - Answer-longer and weaker than covalent O-H bond.
Linear>bent
Number of bonds in liquid water - Answer-3.4
Number of bonds in ice - Answer-4
lifetime of hydrogen bond - Answer-1-20 picoseconds so liquid water is described as
"flickering structure"
Hydrogen bond donor - Answer-Hydrogen in N-H, O-H
Hydrogen bond acceptors - Answer-N: and O:
Rank the strength of Noncovalent interactions - Answer-1. Hydrophobic interactions
2. Pi Stacking
3. Van der Waals
4. Hydrogen bond
5. Electrostatic
6. Salt bridge
Amphipathic interaction - Answer-both hydrophilic and hydrophobic
Ion water product - Answer-Kw= [H+][OH-]= 1x10^-14 M^2
pH equation - Answer-pH = -log[H+]
Acid dissociation constant - Answer-Ka = K[H2O] = [H+][A-]/[HA]
pKa equation - Answer-pKa = -logKa
High Ka - Answer-acid dissociates a lot in solution, strong acid
Low pKa - Answer-strong acid
pH=pKa - Answer-[HA]=[A-]
, Henderson-Hasselbalch equation - Answer-pH = pKa + log [A-]/[HA]
Buffers - Answer-Consist of an aqueous solution of a weak acid and its conjugate base.
resist changes in pH when small amount of acid or base are added
Transcription - Answer-Creates a complementary RNA copy (mRNA) of a sequence of
DNA
Translation - Answer-mRNA is decoded by ribosome and tRNA is used to produce a
specific amino acid chain, or polypeptide, that will later fold into an active protein
Charge of amino acid - Answer-charge is dependent on pH of solution, +1,0, or -1
Isoelectric point - Answer-pI=pH average charge is 0
Isoelectric point equation - Answer-pI=(pKa1+pKa2)/2
4 different groups - Answer-chiral
at least 2 of the 4 groups the same - Answer-achiral
Alpha carbon - Answer-central carbon, chiral center
look along H-Calpha bond and read clockwise to spell CORN for L-configuration
Disulfide bonds - Answer-pairs of cysteines can oxidize to form cystine through a
disulfide bond
peptide bond formation - Answer-a molecule of water is expelled in a condensation
reaction that requires ATP
-amino acids are added to C-terminal
peptide bond structure - Answer-shorter and is not able to rotate due to double bond
character
C-N 1.32A
-coplanar
Peptide bond torsion angles - Answer-phi= Calpha-N
psi= C=O to Calpha
omega= C=O to N
Peptide bond configuations - Answer-Trans is more stable bc omega is restricted to 180
degrees. Except in proline
Polypeptide nomenclature - Answer-N-terminus on the left and C-terminus on the right.
Name AA's in order starting at N-terminus w every AA ending in -yl expect C-terminus
