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 At its isoelectric point, a protein has:
A. Negative charge.
B. Partial negative charge.
C. Partial positive charge.
D. Positive charge.
E. Zero net charge.
 At its isoelectric point, aspartic acid has a net charge equal:
A. +2
B. +1
C. 0
D. -1
E. -2
 Which one of the following amino acids is the uncharged derivative of an
acidic amino acid:
A. Arginine.

B. Glutamine.
C. Histidine.
D. Isoleucine.
E. Leucine.
 Which of the following molecule is amphoteric?
A. Hydrochloric acid.
B. Ammonia.
C. Acetic acid.
D. Sodium acetate.
E. Glycine.
 Which of the following amino acids has a positively charged side chain:
A. Arginine.
B. Aspartic acid.
C. Aspargine.
D. Glutamic acid.

E. Glutamine.
 Which of the following amino acids has a negatively charged side chain:
A. Arginine.
B. Aspartic acid.
C. Aspargine.
D. Glycine.
E. Glutamine.
1) Disulfide bonds, which play an important role in stabilizing
the folded conformation of protein involve the reaction
between:
a. Cysteine and Methionine residues.
b. Glutamine and Serine residues.
c. Two Cysteine residues.
d. Two Methionine residues.
e. Two Serine residues.

2) Which one of the following is a tripeptide and plays an
important role as a reducing agent in the cell:
a. Alanyl-glycine.
b. Aspartyl-phenylalanine
c. Glutathione.
d. Oxytocin.
e. Vasopressin.
3) The net charge of glutamic acid in acidic solution is:
a. -1
b. -2
c. 0
d. +1
e. +2
4) Tyrosine is a/an:
a. Acidic amino acid.
b. Aliphatic amino acid.
Ph=7 Ph=1 Ph=13
Natural 0 +1 -1
Acidic -1 +1 -2
Basic +1 +2 -1

c. Aromatic amino acid.
d. Nonpolar amino acid.
e. Semi-essential amino acid.
5) Which one of the following amino acid has a branched
hydrocarbon chain:
a. Histidine.
b. Isoleucine.
c. Methionine.
d. Phenylalanine.
e. Tyrosine.
6) Methionine is a:
a. Acidic amino acid.
b. Charged polar amino acid.
c. Polar amino acid.
d. Semi- essential amino acid.
e. Sulfur containing amino acid.

7) Found mainly in the connective tissue:
a. Alanine and argnine.
b. Asparagine and aspartic acid
c. Glutamine and glutamic.
d. Hydroxyproline and hydroxylysine.
e. Proline and lysine.
8) The term ‘primary structure’ of protein refers to the:
a. -helical region of the protein.
b. Geometrical organization of the polypeptide chain.
c. Number of amino acid residues present in the protein.
d. Sequence of amino acid in the protein.
e. Total amino acid composition of the protein.
9) Biologically active peptide:

a. Glutathione.
b. Glutamine.
c. Glycogen.
d. Hemoglobin.
e. Methionine.
10) Histamine is produced in the human body by:
a. Deamination of histidine
b. Decarboxylation of histidine.
c. Oxidation of histidine.
d. Oxidative-Deamination of histidine.
e. Transamination of histidine.
11) Protein denaturation involves:
a. Cleavage of peptide bonds between all amino acids.
b. Cleavage of peptide bonds between some amino acids.
c. Conversion of L-amino acids to D-configuration.
d. Folding of polypeptide chain into compact structure.

e. Unfolding of compact, native conformation.
12) A peptide bond:
a. Has a partial double bond character.
b. Is ionized at physiologic pH.
c. Is cleaved by urea and ethanol.
d. Is stable to heating in strong acids.
e. Occurs usually in cis-configuration.
13) Hemoglobin consists of:
a. Four Identical polypeptide chains.
b. Four polypeptide chains (2 Alpha and 2 Beta).
c. Only one polypeptide chain.
d. Two different polypeptide chains (1 Alpha and 1 Beta).
e. Two Identical polypeptide chains.

14) Which one of the following statements about protein
structure is correct?
a. Proteins consisting of one polypeptide chain can have
quaternary structure.
b. Disulfide bond formation requires two adjacent cysteine
residues in the primary sequence of protein.
c. Stability of tertiary structure in proteins is mainly a result of
covalent bonds among the subunits.
d. The denaturation of proteins always leads to irreversible loss of
secondary and tertiary structure.
e. Information required for the correct folding of a protein
is contained in the primary structure of protein.
19.2) Which of the following is NOT a nutritionally essential amino acid?
a) Lysine

b) Leucine
c) Threonine
d) Asparagine
e) Valine
19.3) Which of the following is NOT a nutritionally essential amino acid?
a) Histidine
b) Proline
c) Methionine
d) Phenylalanine
e) Tryptophan
Which of the following is NOT a polar, uncharged amino acid?
a) Asparagine
b) Aspartate
c) Glutamine
d) Serine
e) Threonine
3.2) Which of the following is NOT a charged amino acid?
a) Histidine
b) Lysine
c) Arginine

d) Glutamate
e) Valine
3.3) Which of the following is NOT a nonpolar, aliphatic amino acid?
a) Glycine
b) Alanine
c) Cysteine
d) Leucine
e) Isoleucine
4.1) Which of the following amino acids contains sulfur
a) Methionine
b) Histidine
c) Leucine
d) Tyrosine
e) Glutamate
4.2) Which of the following amino acids is negatively charged (acidic)?
a) Lysine
b) Glutamate
c) Arginine
d) Histidine
e) Serine

5.1) What amino acid has ornithine (role in urea production) as a derivative?
a) Histidine
b) Arginine
c) Cysteine
d) Glycine
e) Serine
5.2) What amino acid has melatonin (pineal gland secretion) as a derivative?
a) Phenylalanine
b) Arginine
c) Cysteine
d) Tryptophan
e) Serine
5.3) What amino acid has histamine (role in anti-inflammatory response) as a
derivative?
a) Histidine
b) Arginine
c) Cysteine
d) Glycine
e) Serine

1) How are amino acids arranged in a primary protein structure?
a) Helical
b) Crossed
c) Folded
d) Perpendicular
e) Linear
2.1) Which of the following characterizes"-helix regions of proteins?
a) They all have the same primary structure
b) They are formed principally by hydrogen bonds between a carbonyl
oxygen atom in one peptide bond and the amide hydrogen from a
different peptide bond
c) They are formed principally by hydrogen bonds between a carbonyl atom in
one peptide bond and the hydrogen atoms on the side chain of another amino
acid
d) They are formed by hydrogen bonding between two adjacent amino acids
in the primary sequence
e) They require a high content of proline and glycine
2.2) In contrast with the"-helix,!-sheets form:
a) With the peptide hydrogen bonds on the same strand
b) With the peptide hydrogen bonds on an adjacent strand

c) With covalent bonding
d) With ionic bonding
e) With peptide bonds between a carbonyl oxygen and an amide
.1) What helps distinguish globular proteins from fibrous proteins?
a)"-helices
b)!-sheets
c) Molecular weight
d) Freezing/melting point
e) Solubility
5) What protein structure refers to the association of individual polypeptide
chain subunits in a geometrically and stoichiometrically specific manner?
a) Primary
b)"-helix
c)!-sheet
d) Tertiary
e) Quaternary
.2) A protein has one transmembrane domain composed entirely of an"-helical
secondary structure. Which of the following amino acids would you expect to
find in the transmembrane domain?

a) Proline
b) Glutamate
c) Lysine
d) Leucine
e) Arginine
15) For amino acids with neutral R groups, at any pH below the pI of the
amino acid, the population of amino acids in solution will have:
a. a net negative charge
b. a net positive charge
c. no charged groups
d. no net charge
e. positive and negative charges in equal concentration
16) Which arrangement of atoms in the peptide backbone is planar?
a. C-N-O
b. C-O-C
c. N-C-O
d. N-O-C
e. C-N-C
17) Which of the following pentapeptides would have the greatest light absorption
at 280 nm?
a. Tyr-Ile-Glu-Met-Phe
b. Set-Thr-Gln-Asn-Tyr
c. Asp-Gly-Trp-Phe-Trp
d. Phe-Phe-Lau-Met-Val
e. Leu-Leu-Met-Ile-Tyr

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