Deck 21: Amino Acids, Peptides, and Proteins

Question 1

Which of the following amino acids has a hydroxy-containing R group?

A) asparagine
B) cysteine
C) proline
D) serine
E) valine

Answer 1

serine

Question 2

Which structure is naturally occurring isoleucine, which is(2S,3S)-2-amino-3-methylpentanoic acid?

A)
B)
C)
D)
E) B and C

Answer 2

Question 3

Which L-amino acid has the R configuration at the ?-position?

A) tyrosine
B) cysteine
C) aspartate
D) leucine
E) methionine

Answer 3

cysteine

Question 4

Which structure does tyrosine have at pH 7.3?

A)
B)
C)
D)
E)

Question 5

What is the isoelectric point (pI) of arginine?

A) 2.17
B) 7.90
C) 9.04
D) 10.76
E) 12.48

Question 6

Which of the following amino acids will elute first during cation-exchange chromatography at pH 7?

A) aspartate
B) isoleucine
C) lysine
D) proline
E) threonine

Question 7

Which method forms leucine from 1-bromo-3-methylbutane?

A) HVZ
B) reductive amination
C) acetamidomalonic ester
D) Strecker
E) Kiliani-Fischer

Question 8

What is the name of this tripeptide?

A) Val-Asn-Thr
B) Leu-Asn-Ser
C) Val-Gln-Thr
D) Leu-Gln-Thr
E) Val-Asn-Thr valine _threonine asparagine

Question 9

Regarding the strategy of peptide synthesis, which statement is true?

A) The N-terminal amino acid is protected using a t-BOC group.
B) The N-protected amino acid is activated using DCCD.
C) The reaction of the second amino acid with the first proceeds by way of nucleophilic acyl substitution.
D) Removing the protecting group drives the reaction to the completion.
E) all of the above

Question 10

Which of the following statements is not true about the Merrifield automated solid-phase peptide synthesis?

A) It provides a faster way of producing peptides.
B) It produces peptides in high yields.
C) It allows for synthesis of peptides containing up to 1000 amino acid residues.
D) It uses a solid support technique allowing easy purification after each step.
E) It allows synthesis of proteins that differ by one or a few
Amino acids.
The Merrifield method is practical for proteins
Of 100 amino acid residues or fewer.

Question 11

The ____________ structure is the three-dimensional shape of the entire polypeptide.

A) Primary
B) secondary
C) tertiary
D) Quaternary
E) Molecular