Question 1

Which of the following amino acids has an uncharged polar side chain at pH 7.0?

Accepted Answer

A) Arg 
B) Thr 
C) Glu 
D) Pro 
E) Ile 
A) Arg 
B) Thr 
C) Glu 
D) Pro 
E) Ile B

Question 2

the diagram shown below.  
-What is the three-letter symbol for the C-terminal amino acid in the peptide shown above?

Accepted Answer

A) Gly 
B) Asp 
C) Tyr 
D) Met 
E) Phe 
A) Gly 
B) Asp 
C) Tyr 
D) Met 
E) Phe E

Question 3

the diagram below.  
-What is the name of this molecule?

Accepted Answer

A) GABA 
B) thyroxine 
C) ($\gamma$-carboxyglutamate) 
D) glutathione 
E) epinephrine 
A) GABA 
B) thyroxine 
C) ($\gamma$-carboxyglutamate) 
D) glutathione 
E) epinephrine D

Question 4

Which of the following tripeptides would be expected to be the most hydrophobic?

Accepted Answer

A) KYG 
B) KYA 
C) GYA 
D) DYA 
E) DYG 
A) KYG 
B) KYA 
C) GYA 
D) DYA 
E) DYG

Question 5

The figure below shows the predominant structure of an oligopeptide at pH 7.0.   a.How many amino acids are present in this peptide?
b.Circle one peptide bond in this peptide.
c.Draw a square around one alpha carbon in this peptide
d.The pKas of the ionizable groups in this peptide are 2.0, 4.0, and 9.0.What is the ionic charge of this molecule at pH 1.0
e.What is the name of the N-terminal amino acid in this peptide?

Accepted Answer

a.5
b. @#IMG-DLM& 
c.@#IMG-DLM& 
d.The charge of this molecu

Question 6

Matching
-At a pH above its pKa, the phenol group of tyrosine is ______.

Accepted Answer

A) glutamate 
B) uncharged 
C) deprotonated 
D) three 
E) amino group
F)two
G)C-terminus
H)lysine
I)racemic mixture
J)cysteine
K)zero
L)protonated
M)isoleucine
N)tryptophan
O)phenylalanine
P)N-terminus 
A) glutamate 
B) uncharged 
C) deprotonated 
D) three 
E) amino group
F)two
G)C-terminus
H)lysine
I)racemic mixture
J)cysteine
K)zero
L)protonated
M)isoleucine
N)tryptophan
O)phenylalanine
P)N-terminus

Question 7

All amino acids derived from proteins have the same stereochemical conformation as.

Accepted Answer

A) L-glyceraldehyde. 
B) (R)-alanine. 
C) D-glucose. 
D) (S)-cysteine. 
E) glycine. 
A) L-glyceraldehyde. 
B) (R)-alanine. 
C) D-glucose. 
D) (S)-cysteine. 
E) glycine.

Question 8

Matching
-At a pH below its pKa, the $\varepsilon$-amino group of lysine is ______.

Accepted Answer

A) glutamate 
B) uncharged 
C) deprotonated 
D) three 
E) amino group
F)two
G)C-terminus
H)lysine
I)racemic mixture
J)cysteine
K)zero
L)protonated
M)isoleucine
N)tryptophan
O)phenylalanine
P)N-terminus 
A) glutamate 
B) uncharged 
C) deprotonated 
D) three 
E) amino group
F)two
G)C-terminus
H)lysine
I)racemic mixture
J)cysteine
K)zero
L)protonated
M)isoleucine
N)tryptophan
O)phenylalanine
P)N-terminus

Question 9

Matching
-In the tripeptide Lys─Pro─Ile, there are ______ charged groups at pH 7.

Accepted Answer

A) glutamate 
B) uncharged 
C) deprotonated 
D) three 
E) amino group
F)two
G)C-terminus
H)lysine
I)racemic mixture
J)cysteine
K)zero
L)protonated
M)isoleucine
N)tryptophan
O)phenylalanine
P)N-terminus 
A) glutamate 
B) uncharged 
C) deprotonated 
D) three 
E) amino group
F)two
G)C-terminus
H)lysine
I)racemic mixture
J)cysteine
K)zero
L)protonated
M)isoleucine
N)tryptophan
O)phenylalanine
P)N-terminus

Question 10

Which of the following amino acids has a sulfur atom in its side chain?

Accepted Answer

A) Asn 
B) Ser 
C) Phe 
D) Met 
E) Tyr 
A) Asn 
B) Ser 
C) Phe 
D) Met 
E) Tyr

Question 11

Which one of the representations describes the oligopeptide shown below?

Accepted Answer

A) Tyr-Ala-Thr 
B) Tyr-Gly-Cys 
C) Tyr-Ala-Ser 
D) Phe-Gly-Cys 
E) Phe-Ala-Thr 
A) Tyr-Ala-Thr 
B) Tyr-Gly-Cys 
C) Tyr-Ala-Ser 
D) Phe-Gly-Cys 
E) Phe-Ala-Thr

Question 12

What percentage of the 20 amino acids is considered to be nutritionally essential to lab animals?

Accepted Answer

A) 0% 
B) 25% 
C) 50% 
D) 75% 
E) 100% 
A) 0% 
B) 25% 
C) 50% 
D) 75% 
E) 100%

Question 13

What is the three-letter abbreviation for the peptide valylarginylisoleucine?

Accepted Answer

A) Val─Arg─Ile 
B) Val─Agn─Leu 
C) Vln─Arg─Ile 
D) Val─Agn─Isl 
E) Vln─Arg─Leu 
A) Val─Arg─Ile 
B) Val─Agn─Leu 
C) Vln─Arg─Ile 
D) Val─Agn─Isl 
E) Vln─Arg─Leu

Question 14

The peptide AYDG has an N-terminal _________ residue.

Accepted Answer

A) glycine 
B) glutamic acid 
C) glutamine 
D) aspartic acid 
E) alanine 
A) glycine 
B) glutamic acid 
C) glutamine 
D) aspartic acid 
E) alanine

Question 15

Which of the amino acids represented below has two chiral centers?

Accepted Answer

A) Ala 
B) Leu 
C) Ile 
D) Pro 
E) Asn 
A) Ala 
B) Leu 
C) Ile 
D) Pro 
E) Asn

Question 16

In general, amino acids are chiral molecules that act as building blocks for proteins.In addition, amino acids and amino acid derivative can act as extracellular messenger molecules such as hormones or neurotransmitters.
a.How many different amino acids can be incorporated into proteins during translation?
b.Do ribosomes use L or D amino acids for protein synthesis?
c.Name one amino acid or amino acid derivative that can act as hormone or neurotransmitter.
d.Draw the predominant structure of valine at pH 10 (pKas are 2.3 and 9.7).

Accepted Answer

a.20
b.L
c.glycine,

Question 17

The pK1, pK2, and pKR 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:

Accepted Answer

A) ($\alpha$-carboxylate +1, $\alpha$-amino 0, $\gamma$-carboxylate +1, net charge +2) 
B) ($\alpha$-carboxylate −1, $\alpha$-amino +1, $\gamma$-carboxylate −1, net charge −1) 
C) ($\alpha$-carboxylate 0, $\alpha$-amino 0, $\gamma$-carboxylate 0, net charge 0) 
D) ($\alpha$-carboxylate +1, $\alpha$-amino −1, $\gamma$-carboxylate +1, net charge +1) 
E) ($\alpha$-carboxylate −1, $\alpha$-amino 0, $\gamma$-carboxylate −1, net charge −2) 
A) ($\alpha$-carboxylate +1, $\alpha$-amino 0, $\gamma$-carboxylate +1, net charge +2) 
B) ($\alpha$-carboxylate −1, $\alpha$-amino +1, $\gamma$-carboxylate −1, net charge −1) 
C) ($\alpha$-carboxylate 0, $\alpha$-amino 0, $\gamma$-carboxylate 0, net charge 0) 
D) ($\alpha$-carboxylate +1, $\alpha$-amino −1, $\gamma$-carboxylate +1, net charge +1) 
E) ($\alpha$-carboxylate −1, $\alpha$-amino 0, $\gamma$-carboxylate −1, net charge −2)

Question 18

The pK1, pK2, and pKR 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:

Accepted Answer

A) ($\alpha$-carboxylate 0, $\alpha$-amino −1, $\varepsilon$-amino −1, net charge −2) 
B) ($\alpha$-carboxylate −1, $\alpha$-amino +1, $\varepsilon$-amino +1, net charge +1) 
C) ($\alpha$-carboxylate +1, $\alpha$-amino +2, $\varepsilon$-amino +2, net charge +5) 
D) ($\alpha$-carboxylate 0, $\alpha$-amino +1, $\varepsilon$-amino +1, net charge +2) 
E) ($\alpha$-carboxylate +2, $\alpha$-amino +1, $\varepsilon$-amino +1, net charge +4) 
A) ($\alpha$-carboxylate 0, $\alpha$-amino −1, $\varepsilon$-amino −1, net charge −2) 
B) ($\alpha$-carboxylate −1, $\alpha$-amino +1, $\varepsilon$-amino +1, net charge +1) 
C) ($\alpha$-carboxylate +1, $\alpha$-amino +2, $\varepsilon$-amino +2, net charge +5) 
D) ($\alpha$-carboxylate 0, $\alpha$-amino +1, $\varepsilon$-amino +1, net charge +2) 
E) ($\alpha$-carboxylate +2, $\alpha$-amino +1, $\varepsilon$-amino +1, net charge +4)

Question 19

The formation of a dipeptide from two amino acids involves

Accepted Answer

A) side-chain complementarity. 
B) loss of water. 
C) oxidation of the $\alpha$-carbon. 
D) reduction of the $\alpha$-carbon. 
E) base catalysis. 
A) side-chain complementarity. 
B) loss of water. 
C) oxidation of the $\alpha$-carbon. 
D) reduction of the $\alpha$-carbon. 
E) base catalysis.

Question 20

the diagram shown below.  
-How many amino acid residues are present in the peptide shown above?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 5 
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Exam 4: Amino Acids

Which of the following amino acids has an uncharged polar side chain at pH 7.0?

the diagram shown below. -What is the three-letter symbol for the C-terminal amino acid in the peptide shown above?

the diagram below. -What is the name of this molecule?

Which of the following tripeptides would be expected to be the most hydrophobic?

Matching -At a pH above its pKa, the phenol group of tyrosine is ______.

All amino acids derived from proteins have the same stereochemical conformation as.

Matching -At a pH below its pKa, the ε\varepsilonε -amino group of lysine is ______.

Matching -In the tripeptide Lys─Pro─Ile, there are ______ charged groups at pH 7.

Which of the following amino acids has a sulfur atom in its side chain?

Which one of the representations describes the oligopeptide shown below?

What percentage of the 20 amino acids is considered to be nutritionally essential to lab animals?

What is the three-letter abbreviation for the peptide valylarginylisoleucine?

The peptide AYDG has an N-terminal _________ residue.

Which of the amino acids represented below has two chiral centers?

The pK1, pK2, and pKR 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:

The pK1, pK2, and pKR 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:

The formation of a dipeptide from two amino acids involves

the diagram shown below. -How many amino acid residues are present in the peptide shown above?

Introduction to the Chemistry of Life

Water

Nucleotides, Nucleic Acids, and Genetic Information

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Enzyme Kinetics, Inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glycogen Metabolism and Gluconeogenesis

Glucose Catabolism

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

Dna Replication, Repair and Recombination

Transcription and Rna Processing

Translation

Regulation of Gene Expression

Filters

Matching -At a pH above its pK_a, the phenol group of tyrosine is ______.

Matching -At a pH below its pK_a, the $\varepsilon$ -amino group of lysine is ______.

The pK₁, pK₂, 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:

The pK₁, pK₂, 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: