BIOCHEMISTRY FOURTH EDITION ACTUAL
ASSESSMENT SCRIPT 2026 COMPLETE
QUESTIONS SOLUTIONS GRADED A PLUS
◉ Of the 20 common amino acids, how many have a chiral α-carbon?
a. 0
b. 1 c. 19 d. 20
Answer: C
◉ The chirality of naturally occurring amino acids in proteins is
a. R.
b. L.
c. D.
d. the same as glyceraldehyde.
Answer: B
◉ At what point does the isoelectric point or pI occur?
a. when all of the acidic protons are neutralized with base
b. atpH=7.0
,c. at the pH when all negative charges on a zwitterion counter the
positive charges
d. when the molecule has a single electric charge
Answer: C
◉ For the alanine titration curve shown below, which best describes
point A? *see pdf #4 for picture*
a. a buffer region
b. isoelectric point
c. second equivalence point
d. pH=pKa
Answer: B
◉ If the titration curve shown below is for the amino acid glycine, at
which point in the curve is the pI?
*see #6 for pic*
a. A b. B c. C d. D
Answer: C
◉ If the isoelectric point (pI) for an amino acid is at point A, what is
the charge on the amino acid at point B? *see #7 for pic*
a. 0 b. −2 c. +2 d. −1
Answer: B
, ◉ A polypeptide has a high pI value. Which amino acids might
compromise it?a. arginine and lysine residues
b. aspartate and glutamate residues
c. the large nonpolar amino acids
d. a mixture of aspartate and arginine residues
Answer: A
◉ Using the pKas shown, what is the isoelectric point of the amino
acid tyrosine? *see number 9*
a. <1.0 b. 5.5 c. 7.0 d. 9.75
Answer: B
◉ What is the pI of the dipeptide shown? (Use the pK as given.) *see
number 10*
a. 0
b. 5
c. 9
d. 10.5
Answer: B
◉ Which amino acid contains a hydroxyl group? a. valine
ASSESSMENT SCRIPT 2026 COMPLETE
QUESTIONS SOLUTIONS GRADED A PLUS
◉ Of the 20 common amino acids, how many have a chiral α-carbon?
a. 0
b. 1 c. 19 d. 20
Answer: C
◉ The chirality of naturally occurring amino acids in proteins is
a. R.
b. L.
c. D.
d. the same as glyceraldehyde.
Answer: B
◉ At what point does the isoelectric point or pI occur?
a. when all of the acidic protons are neutralized with base
b. atpH=7.0
,c. at the pH when all negative charges on a zwitterion counter the
positive charges
d. when the molecule has a single electric charge
Answer: C
◉ For the alanine titration curve shown below, which best describes
point A? *see pdf #4 for picture*
a. a buffer region
b. isoelectric point
c. second equivalence point
d. pH=pKa
Answer: B
◉ If the titration curve shown below is for the amino acid glycine, at
which point in the curve is the pI?
*see #6 for pic*
a. A b. B c. C d. D
Answer: C
◉ If the isoelectric point (pI) for an amino acid is at point A, what is
the charge on the amino acid at point B? *see #7 for pic*
a. 0 b. −2 c. +2 d. −1
Answer: B
, ◉ A polypeptide has a high pI value. Which amino acids might
compromise it?a. arginine and lysine residues
b. aspartate and glutamate residues
c. the large nonpolar amino acids
d. a mixture of aspartate and arginine residues
Answer: A
◉ Using the pKas shown, what is the isoelectric point of the amino
acid tyrosine? *see number 9*
a. <1.0 b. 5.5 c. 7.0 d. 9.75
Answer: B
◉ What is the pI of the dipeptide shown? (Use the pK as given.) *see
number 10*
a. 0
b. 5
c. 9
d. 10.5
Answer: B
◉ Which amino acid contains a hydroxyl group? a. valine
