BIOCHEMISTRY ACTUAL EXAM TEST BANK
2026 QUESTIONS WITH ANSWERS GRADED
A+
◉The amino and carboxyl groups of amino acids react in a head-to-tail
fashion, eliminating water, and forming a covalent ____ linkage
typically referred to as a(n) ____ bond.
a. ester, aromatic
b. anhydride,phosphoanhydride
c. amide, peptide
d. dehydration, hydrogen
e. none of the above.ANSWER:-amide, peptide
◉All of the statements about the classification of these amino acids are
correct EXCEPT:
a. Aspartic acid and asparagine are acidic amino acids.
b. Alanine and valine are neutral, nonpolar amino acids.
c. Serine and glutamine are polar, uncharged amino acids.
,d. Lysine and arginine are basic amino acids.
e. Tyrosine and phenylalanine are aromatic amino acids..ANSWER:-
Aspartic acid and asparagine are acidic amino acids.
◉The difference between serine and homoserine is the same as between
cysteine and homocysteine. This change from
the common amino acid is:
a. one additional methylene (−CH2−) group.
b. one additional carboxyl group.
c. two additional amine groups.
d. presence of a ring system.
e. one additional amine group..ANSWER:-one additional methylene
(−CH2−) group.
◉Which of the following amino acids has more than one chiral carbon?
a. serine
b. lysine
,c. threonine
d. cysteine
e. aspartic acid.ANSWER:-threonine
◉Which of the listed amino acids is classified as a basic amino acid?
a. leucine
b. phenylalanine
c. aspartate
d. asparagine
e. lysine.ANSWER:-lysine
◉All of the amino acids EXCEPT ____ have both free α-amino and free
α-carboxyl groups.
a. aspartic acid
b. proline
c. asparagine
d. lysine
e. valine.ANSWER:-proline
◉The amino acid with a side-chain pKa near neutrality and which
therefore plays an important role as proton donor and acceptor in many
enzyme catalyzed reactions is:
, a. histidine.
b. cysteine.
c. proline.
d. serine.
e. methionine..ANSWER:-histidine
◉The pKa of the α−carboxyl group of an amino acid is ____ by the
presence on the amine group.
a. greatly increased (>2 pH units)
b. greatly decreased (> 2 pH units)
c. unchanged
d. slightly increased (1-2 pH units)
e. slightly decreased (1-2 pH units).ANSWER:-greatly decreased (> 2
pH units)
◉At which of the following pH values would histidine (pKa values of
1.8, 6.0 and 9.2) be found with a net negative
charge?
2026 QUESTIONS WITH ANSWERS GRADED
A+
◉The amino and carboxyl groups of amino acids react in a head-to-tail
fashion, eliminating water, and forming a covalent ____ linkage
typically referred to as a(n) ____ bond.
a. ester, aromatic
b. anhydride,phosphoanhydride
c. amide, peptide
d. dehydration, hydrogen
e. none of the above.ANSWER:-amide, peptide
◉All of the statements about the classification of these amino acids are
correct EXCEPT:
a. Aspartic acid and asparagine are acidic amino acids.
b. Alanine and valine are neutral, nonpolar amino acids.
c. Serine and glutamine are polar, uncharged amino acids.
,d. Lysine and arginine are basic amino acids.
e. Tyrosine and phenylalanine are aromatic amino acids..ANSWER:-
Aspartic acid and asparagine are acidic amino acids.
◉The difference between serine and homoserine is the same as between
cysteine and homocysteine. This change from
the common amino acid is:
a. one additional methylene (−CH2−) group.
b. one additional carboxyl group.
c. two additional amine groups.
d. presence of a ring system.
e. one additional amine group..ANSWER:-one additional methylene
(−CH2−) group.
◉Which of the following amino acids has more than one chiral carbon?
a. serine
b. lysine
,c. threonine
d. cysteine
e. aspartic acid.ANSWER:-threonine
◉Which of the listed amino acids is classified as a basic amino acid?
a. leucine
b. phenylalanine
c. aspartate
d. asparagine
e. lysine.ANSWER:-lysine
◉All of the amino acids EXCEPT ____ have both free α-amino and free
α-carboxyl groups.
a. aspartic acid
b. proline
c. asparagine
d. lysine
e. valine.ANSWER:-proline
◉The amino acid with a side-chain pKa near neutrality and which
therefore plays an important role as proton donor and acceptor in many
enzyme catalyzed reactions is:
, a. histidine.
b. cysteine.
c. proline.
d. serine.
e. methionine..ANSWER:-histidine
◉The pKa of the α−carboxyl group of an amino acid is ____ by the
presence on the amine group.
a. greatly increased (>2 pH units)
b. greatly decreased (> 2 pH units)
c. unchanged
d. slightly increased (1-2 pH units)
e. slightly decreased (1-2 pH units).ANSWER:-greatly decreased (> 2
pH units)
◉At which of the following pH values would histidine (pKa values of
1.8, 6.0 and 9.2) be found with a net negative
charge?
