BCH 400 final review
What is the main purpose of using a CRISPR-Cas system?
a) Tag proteins with fluorescent molecules
b) Amplify DNA
c) Site-specifically modify genomes
d) Sequence RNA - correct answer ✔✔c) Site-specifically modify genomes
Which of the following features is NOT associated with a peptide bond (i.e, not true)?
a. It can freely rotate to generate different phi and psi angles
b. it is stabilized by a resonance structure
c. it has a partial double bond character
d. it is stable at pH 7
e. It is stable in the presence of beta-mercaptoethanol (e.g, 1mM) - correct answer ✔✔a. It can freely
rotate to generate different phi and psi angles
Given that Carbon has an atomic number of 6, how many unpaired electrons are expected in its outer
shell(reminder, this number is equal to the number of covalent bonds that C "likes" to form)
a) 1
b) 2
c)3
d) 4
e) 6 - correct answer ✔✔d) 4
3. For the pathway that makes the signaling molecules Serotonin and Melatonin, which of the following
is considered the amino acid precursor.
a) Serine
b) Tryptophan
,c) Phenylalanine
d) Taurine - correct answer ✔✔b) tryptophan
4. In creating a proinsulin cDNA molecule, the enzyme used to synthesize DNA from an RNA template is
mostlikely which of the following___________
a) Restriction endonucleases
b) Reverse transcriptase
c) T4 ligase
d) Taq polymerase - correct answer ✔✔b) Reverse transcriptase
if a water solution has a [OH-] concentration of 1 X 10-7, the pH would likely be:
a) 4
b) 5
c) 6
d) 7
e) 8 - correct answer ✔✔d) 7
you are given an HCl (strong acid) solution with a pH = 2. If you dilute 1 mL of the solution with water
into a total of 100 mL (i.e., a 100-fold dilution), the resulting pH will be closest to ___________.
a) 1
b) 2
c) 3
d) 4
e) 5 - correct answer ✔✔d) 4
Which of the following pairs of atoms is most likely an incorrect assignment of relative electronegativity?
a) O > F
b) N > S
c) C > P
,d) P > H
e) N > C - correct answer ✔✔a) O > F
What is the major thermodynamic force that drives non-polar surfaces out of contact with an aqueous
solution(e.g., in the globular structure of myoglobin)
a) Increased entropy of solvent water molecules
b) Increased enthalpy of H-bonds in solvent water
c) Increased entropy of newly organized solute molecules
d) Increased enthalpy of hydrophobic bonds formed between solute moleculee) Decreased entropy of
newly organized solute molecules - correct answer ✔✔a) Increased entropy of solvent water molecules
Which of the following is the most incorrect approximation of distance or unit of measure?
a) Ribosomes have a diameter of ~ 20 nm (and would pass through a 0.2 μm sterilization filter)
b) Concentration of OH- at pH 7 = 1 M
c) Bond distance between O and H in a H20 molecule is ~ 1 Angstrom
d) Distance between O and H in a hydrogen bond between two H20 molecules is ~ 2 x 10-10 m - correct
answer ✔✔b) Concentration of OH- at pH 7 = 1 M
The titration curves for all 20 aa can be described by the pKa values (Table "3.2" below) associated with
the amino and carboxyl groups attached to the alpha carbon, as well as the functional groups associated
with the Rgroup side chains.
A titration of Gly (G) from pH 1 to 14 would reveal 2 distinct pKas.
a) true
b) false - correct answer ✔✔a) true
Lysine (K) would be expected to have its isoelectric point closest to pH ____.
a) 2.2
b) 9.1
c) (2.2+9.1)/2 = 5.65
d) (2.2+10.5)/2 = 6.35
, e) (9.1+10.5)/2 = 9.8 - correct answer ✔✔e) (9.1+10.5)/2 = 9.8
Cysteine (C) would be expected to have its isoelectric pointclosest to pH ____.
a) 1.9
b) 10.7
c) (1.9 + 10.7)/2 = 6.3
d) (1.9 + 8.4)/2 = 4.7
e) (8.4 +10.7)/2 = 9.55 - correct answer ✔✔d) (1.9 + 8.4)/2 = 4.7
For a solution of Histidine (H), what percentage of the sidechain R group would be ionized at pH = 6.0
(i.e., = "+1")
a) 0 %
b) 25 %
c) 50 %
d) 100% - correct answer ✔✔c) 50 %
For a solution of Threonine (T), what percentage ofthe R group's OH would be deprotonated at pH = ~
10.1 (i.e., = O-)?
a) 0 %
b) 25 %
c) 50 %
d) 100% - correct answer ✔✔a) 0 %
16. At which of the following pH(s) would a His (H) be azwitterion (i.e. have no net charge)?
a) 1.8
b) 9.3
c) 6 , 9.3 and 1.8
d) (1.8 + 6.0)/2 = 3.9
e) (9.3 +6.0)/2 = 7.65 - correct answer ✔✔e) (9.3 +6.0)/2 = 7.65
What is the main purpose of using a CRISPR-Cas system?
a) Tag proteins with fluorescent molecules
b) Amplify DNA
c) Site-specifically modify genomes
d) Sequence RNA - correct answer ✔✔c) Site-specifically modify genomes
Which of the following features is NOT associated with a peptide bond (i.e, not true)?
a. It can freely rotate to generate different phi and psi angles
b. it is stabilized by a resonance structure
c. it has a partial double bond character
d. it is stable at pH 7
e. It is stable in the presence of beta-mercaptoethanol (e.g, 1mM) - correct answer ✔✔a. It can freely
rotate to generate different phi and psi angles
Given that Carbon has an atomic number of 6, how many unpaired electrons are expected in its outer
shell(reminder, this number is equal to the number of covalent bonds that C "likes" to form)
a) 1
b) 2
c)3
d) 4
e) 6 - correct answer ✔✔d) 4
3. For the pathway that makes the signaling molecules Serotonin and Melatonin, which of the following
is considered the amino acid precursor.
a) Serine
b) Tryptophan
,c) Phenylalanine
d) Taurine - correct answer ✔✔b) tryptophan
4. In creating a proinsulin cDNA molecule, the enzyme used to synthesize DNA from an RNA template is
mostlikely which of the following___________
a) Restriction endonucleases
b) Reverse transcriptase
c) T4 ligase
d) Taq polymerase - correct answer ✔✔b) Reverse transcriptase
if a water solution has a [OH-] concentration of 1 X 10-7, the pH would likely be:
a) 4
b) 5
c) 6
d) 7
e) 8 - correct answer ✔✔d) 7
you are given an HCl (strong acid) solution with a pH = 2. If you dilute 1 mL of the solution with water
into a total of 100 mL (i.e., a 100-fold dilution), the resulting pH will be closest to ___________.
a) 1
b) 2
c) 3
d) 4
e) 5 - correct answer ✔✔d) 4
Which of the following pairs of atoms is most likely an incorrect assignment of relative electronegativity?
a) O > F
b) N > S
c) C > P
,d) P > H
e) N > C - correct answer ✔✔a) O > F
What is the major thermodynamic force that drives non-polar surfaces out of contact with an aqueous
solution(e.g., in the globular structure of myoglobin)
a) Increased entropy of solvent water molecules
b) Increased enthalpy of H-bonds in solvent water
c) Increased entropy of newly organized solute molecules
d) Increased enthalpy of hydrophobic bonds formed between solute moleculee) Decreased entropy of
newly organized solute molecules - correct answer ✔✔a) Increased entropy of solvent water molecules
Which of the following is the most incorrect approximation of distance or unit of measure?
a) Ribosomes have a diameter of ~ 20 nm (and would pass through a 0.2 μm sterilization filter)
b) Concentration of OH- at pH 7 = 1 M
c) Bond distance between O and H in a H20 molecule is ~ 1 Angstrom
d) Distance between O and H in a hydrogen bond between two H20 molecules is ~ 2 x 10-10 m - correct
answer ✔✔b) Concentration of OH- at pH 7 = 1 M
The titration curves for all 20 aa can be described by the pKa values (Table "3.2" below) associated with
the amino and carboxyl groups attached to the alpha carbon, as well as the functional groups associated
with the Rgroup side chains.
A titration of Gly (G) from pH 1 to 14 would reveal 2 distinct pKas.
a) true
b) false - correct answer ✔✔a) true
Lysine (K) would be expected to have its isoelectric point closest to pH ____.
a) 2.2
b) 9.1
c) (2.2+9.1)/2 = 5.65
d) (2.2+10.5)/2 = 6.35
, e) (9.1+10.5)/2 = 9.8 - correct answer ✔✔e) (9.1+10.5)/2 = 9.8
Cysteine (C) would be expected to have its isoelectric pointclosest to pH ____.
a) 1.9
b) 10.7
c) (1.9 + 10.7)/2 = 6.3
d) (1.9 + 8.4)/2 = 4.7
e) (8.4 +10.7)/2 = 9.55 - correct answer ✔✔d) (1.9 + 8.4)/2 = 4.7
For a solution of Histidine (H), what percentage of the sidechain R group would be ionized at pH = 6.0
(i.e., = "+1")
a) 0 %
b) 25 %
c) 50 %
d) 100% - correct answer ✔✔c) 50 %
For a solution of Threonine (T), what percentage ofthe R group's OH would be deprotonated at pH = ~
10.1 (i.e., = O-)?
a) 0 %
b) 25 %
c) 50 %
d) 100% - correct answer ✔✔a) 0 %
16. At which of the following pH(s) would a His (H) be azwitterion (i.e. have no net charge)?
a) 1.8
b) 9.3
c) 6 , 9.3 and 1.8
d) (1.8 + 6.0)/2 = 3.9
e) (9.3 +6.0)/2 = 7.65 - correct answer ✔✔e) (9.3 +6.0)/2 = 7.65
