TEST BANK FOR BIOCHEMISTRY 2025, 2026 NEWEST AND
VERIFIED|A+ PASS WITNESSED|PROVIDED WITH QUESTIONS
AND ANSWERS
Which of the following amino acids has a charged polar side chain at pH 7.0?
A) Leu
B) Ala
C) Met
D) Trp
E) Glu E
Which of the following tripeptides carries a NET positive charge at pH 7.0?
A) Ala-Thr-Asn
B) Gln-Val-Ser
C) Arg-Glu-Met
D) Pro-Ile-Leu
E) Leu-Lys-Gly E
Which of the following amino acids has a sulfur atom in its side chain?
A) Asn
B) Ser
C) Phe
D) Met
E) Tyr D
Which of the following amino acids does NOT have an ionizable side chain?
,A) Asp
B) Cys
C) Lys
D) His
E) Asn E
Which of the following amino acids has an uncharged polar side chain at pH 7.0?
A) Arg
B) Thr
C) Glu
D) Pro
E) Ile B
What is the structure of Asn?
The ionization of amino acids depends on the pH and the pKas of the ionizable groups. The pK1
and pK2 for the amino acid (Asn shown in previous question) are 2.1 and 8.8, respectively. At
what pH is the amino acid ionized predominantly as shown? pH 1.0
The pK1, pK2, and pKR for the amino acid arginine are 1.8, 9.0, and 12.5, respectively. At pH
7.0 arginine would be charged predominantly as follows: α-carboxylate-1, α-amino+1,
guanidino+1, net charge +1
The pK1, pK2, and pKR for the amino acid aspartic acid are 2.0, 9.9, and 3.9, respectively. At
pH 7.0, aspartic acid would be charged predominantly as follows: α-carboxylate -1, α-amino
+1, β-Carboxylate -1, Net charge -1
The pK 1 , pK 2 , and pK R for the amino acid glutamate are 2.1, 9.5, and 4.1, respectively. At
pH 11.0, glutamate would be charged predominantly as follows: α-carboxylate −1, α-amino 0,
γ-carboxylate −1, net charge −2
The pK 1 , pK 2 , and pK R for the amino acid histidine are 1.8, 9.3, and 6.0, respectively. At pH
4.0 would be charged predominantly as follows: α-carboxylate −1, α-amino +1, imidazole
+1, net charge +1
The pK 1 , pK 2 , and pK R for the amino acid cysteine are 1.9, 10.7, and 8.4, respectively. At
pH
5.0, cysteine would be charged predominantly as follows: α-carboxylate −1, α-amino +1,
sulfhydryl 0, net charge 0
,The pK 1 , pK 2 , and pK R for the amino acid lysine are 2.2, 9.1, and 10.5, respectively. At pH
1.0, lysine would be charged predominantly as follows: α-carboxylate 0, α-amino +1, ε-
amino +1, net charge +2
While proteins are usually composed of linear chains of amino acids, branched chains of amino
acids and internally cross-linked chains can be found in certain proteins. Polypeptide chains are
most commonly linked to each other throughDisulfide Bonds
The disulfide bond betwee two cysteine molecules
A) is a peptide bond.
B) is an ionic interaction that is stable at physiological pH.
C) is a covalent bond formed by oxidation.
D) is a hydrogen bond between the two sulfhydryl groups.
E) is a dipole-dipole interaction. D) Is covalent bond formed by oxidation
The tripeptide glycylarginylglutamate contains four ionizable groups with pKas of 2.1, 4.1, 9.8,
and 12.5. Calculate the pI for this molecule 7.0
The tripeptide alanyllysylaspartate contains four ionizable groups with pKas of 2.0, 3.9, 9.9, and
10.5. Calculate the pI for this molecule.
A) 3.0
B) 6.0
C) 6.2
D) 10.2
E) None of the above E
The isoelectronic point of an amino acid is the point where the amino acid carries no net
electrical charge
The side-chains of amino acids have Different pKas in peptides as compared to the free amino
acids
Axs refers to either aspartic acid or asparganine
The peptide AYDG has an N-terminal ____ residue Alanine
Which of the following tripeptides would be expected to be the most hydrophobic?
, A) KYG
B) KYA
C) GYA
D) DYA
E) DYG C
What is the three-letter abbreviation for the peptide valylarginylisoleucine?
A) Val─Arg─Ile
B) Val─Agn─Leu
C) Vln─Arg─Ile
D) Val─Agn─Isl
E) Vln─Arg─Leu A
Ribosomes use L amino acids to synthesize proteins. These amino acids are called "L" because
They have a configuration of groups around the Cα that an be related to the configuration
of groups around the asymmetric carbon in L-glyceraldehyde
Ribosomes use L amino acids to synthesize proteins. These amino acids are called "L"
because
A) they are chiral.
B) they turn polarized light to the left.
C) they are all (S)-amino acids.
D) they are all (R)-amino acids.
E) none of the above E
Which of the amino acids represented below has two chiral centers?
A) Ala
B) Leu
C) Ile
D) Pro
E) Asn C
All the standard amino acids except ___ are optically active Gly
VERIFIED|A+ PASS WITNESSED|PROVIDED WITH QUESTIONS
AND ANSWERS
Which of the following amino acids has a charged polar side chain at pH 7.0?
A) Leu
B) Ala
C) Met
D) Trp
E) Glu E
Which of the following tripeptides carries a NET positive charge at pH 7.0?
A) Ala-Thr-Asn
B) Gln-Val-Ser
C) Arg-Glu-Met
D) Pro-Ile-Leu
E) Leu-Lys-Gly E
Which of the following amino acids has a sulfur atom in its side chain?
A) Asn
B) Ser
C) Phe
D) Met
E) Tyr D
Which of the following amino acids does NOT have an ionizable side chain?
,A) Asp
B) Cys
C) Lys
D) His
E) Asn E
Which of the following amino acids has an uncharged polar side chain at pH 7.0?
A) Arg
B) Thr
C) Glu
D) Pro
E) Ile B
What is the structure of Asn?
The ionization of amino acids depends on the pH and the pKas of the ionizable groups. The pK1
and pK2 for the amino acid (Asn shown in previous question) are 2.1 and 8.8, respectively. At
what pH is the amino acid ionized predominantly as shown? pH 1.0
The pK1, pK2, and pKR for the amino acid arginine are 1.8, 9.0, and 12.5, respectively. At pH
7.0 arginine would be charged predominantly as follows: α-carboxylate-1, α-amino+1,
guanidino+1, net charge +1
The pK1, pK2, and pKR for the amino acid aspartic acid are 2.0, 9.9, and 3.9, respectively. At
pH 7.0, aspartic acid would be charged predominantly as follows: α-carboxylate -1, α-amino
+1, β-Carboxylate -1, Net charge -1
The pK 1 , pK 2 , and pK R for the amino acid glutamate are 2.1, 9.5, and 4.1, respectively. At
pH 11.0, glutamate would be charged predominantly as follows: α-carboxylate −1, α-amino 0,
γ-carboxylate −1, net charge −2
The pK 1 , pK 2 , and pK R for the amino acid histidine are 1.8, 9.3, and 6.0, respectively. At pH
4.0 would be charged predominantly as follows: α-carboxylate −1, α-amino +1, imidazole
+1, net charge +1
The pK 1 , pK 2 , and pK R for the amino acid cysteine are 1.9, 10.7, and 8.4, respectively. At
pH
5.0, cysteine would be charged predominantly as follows: α-carboxylate −1, α-amino +1,
sulfhydryl 0, net charge 0
,The pK 1 , pK 2 , and pK R for the amino acid lysine are 2.2, 9.1, and 10.5, respectively. At pH
1.0, lysine would be charged predominantly as follows: α-carboxylate 0, α-amino +1, ε-
amino +1, net charge +2
While proteins are usually composed of linear chains of amino acids, branched chains of amino
acids and internally cross-linked chains can be found in certain proteins. Polypeptide chains are
most commonly linked to each other throughDisulfide Bonds
The disulfide bond betwee two cysteine molecules
A) is a peptide bond.
B) is an ionic interaction that is stable at physiological pH.
C) is a covalent bond formed by oxidation.
D) is a hydrogen bond between the two sulfhydryl groups.
E) is a dipole-dipole interaction. D) Is covalent bond formed by oxidation
The tripeptide glycylarginylglutamate contains four ionizable groups with pKas of 2.1, 4.1, 9.8,
and 12.5. Calculate the pI for this molecule 7.0
The tripeptide alanyllysylaspartate contains four ionizable groups with pKas of 2.0, 3.9, 9.9, and
10.5. Calculate the pI for this molecule.
A) 3.0
B) 6.0
C) 6.2
D) 10.2
E) None of the above E
The isoelectronic point of an amino acid is the point where the amino acid carries no net
electrical charge
The side-chains of amino acids have Different pKas in peptides as compared to the free amino
acids
Axs refers to either aspartic acid or asparganine
The peptide AYDG has an N-terminal ____ residue Alanine
Which of the following tripeptides would be expected to be the most hydrophobic?
, A) KYG
B) KYA
C) GYA
D) DYA
E) DYG C
What is the three-letter abbreviation for the peptide valylarginylisoleucine?
A) Val─Arg─Ile
B) Val─Agn─Leu
C) Vln─Arg─Ile
D) Val─Agn─Isl
E) Vln─Arg─Leu A
Ribosomes use L amino acids to synthesize proteins. These amino acids are called "L" because
They have a configuration of groups around the Cα that an be related to the configuration
of groups around the asymmetric carbon in L-glyceraldehyde
Ribosomes use L amino acids to synthesize proteins. These amino acids are called "L"
because
A) they are chiral.
B) they turn polarized light to the left.
C) they are all (S)-amino acids.
D) they are all (R)-amino acids.
E) none of the above E
Which of the amino acids represented below has two chiral centers?
A) Ala
B) Leu
C) Ile
D) Pro
E) Asn C
All the standard amino acids except ___ are optically active Gly
