Question 1

Which of the following is classified as a neutral polar amino acid?

Accepted Answer

A)  Asp 
B)  Leu 
C)  His 
D)  Ser 
E)  Trp 
A)  Asp 
B)  Leu 
C)  His 
D)  Ser 
E)  Trp

Question 2

The peptide bond has partial ____ character.

Accepted Answer

A)  hydrogen bond 
B)  double bond 
C)  triple bond 
D)  van der Waals bond 
E)  all of the above 
A)  hydrogen bond 
B)  double bond 
C)  triple bond 
D)  van der Waals bond 
E)  all of the above

Question 3

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:

Accepted Answer

A)  histidine. 
B)  cysteine. 
C)  proline. 
D)  serine. 
E)  methionine. 
A)  histidine. 
B)  cysteine. 
C)  proline. 
D)  serine. 
E)  methionine.

Question 4

Glutamic acid has pKa values of 2.2, 4.3, and 9.7. Calculate the isoelectric point for glutamic acid.

Accepted Answer

A)  3.25 
B)  4.3 
C)  5.4 
D)  7.0 
E)  8.6 
A)  3.25 
B)  4.3 
C)  5.4 
D)  7.0 
E)  8.6

Question 5

Where Cα is the α-carbon, N represents the amide nitrogen and Co is the carbonyl carbon of amino acids in a peptide, the peptide backbone of a protein consists of the repeated sequence:

Accepted Answer

A)  −Cα−N−Co− 
B)  −N−Co−Cα− 
C)  −N−Cα−Co− 
D)  −Co−Cα−N− 
E)  none of the above 
A)  −Cα−N−Co− 
B)  −N−Co−Cα− 
C)  −N−Cα−Co− 
D)  −Co−Cα−N− 
E)  none of the above

Question 6

What is the pH of a serine solution in which the α−amine group (pKa 9.2) is 33% deprotonated?

Accepted Answer

A)  8.7 
B)  8.9 
C)  9.0 
D)  9.5 
E)  9.8 
A)  8.7 
B)  8.9 
C)  9.0 
D)  9.5 
E)  9.8

Question 7

All of the amino acids EXCEPT ____ have both free α-amino and free α-carboxyl groups.

Accepted Answer

A)  aspartic acid 
B)  proline 
C)  asparagine 
D)  lysine 
E)  valine 
A)  aspartic acid 
B)  proline 
C)  asparagine 
D)  lysine 
E)  valine

Question 8

The pKa of the cysteine side chain ____ group is 8.32, so it is about 11% deprotonated at pH ____.

Accepted Answer

A)  acid, 3.2 
B)  amino, 8.5 
C)  hydroxyl, 10.2 
D)  sulfhydryl, 7.4 
E)  none of the above 
A)  acid, 3.2 
B)  amino, 8.5 
C)  hydroxyl, 10.2 
D)  sulfhydryl, 7.4 
E)  none of the above

Question 9

Discuss the side-chain groups of amino acids that undergo ionizations.​

Accepted Answer

​Histidine contains an ionizable imidazo

Exam 4: Amino Acids and the Peptide Bond

Which of the following is classified as a neutral polar amino acid?

The peptide bond has partial ____ character.

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:

Glutamic acid has pKa values of 2.2, 4.3, and 9.7. Calculate the isoelectric point for glutamic acid.

Where Cα is the α-carbon, N represents the amide nitrogen and Co is the carbonyl carbon of amino acids in a peptide, the peptide backbone of a protein consists of the repeated sequence:

What is the pH of a serine solution in which the α−amine group (pKa 9.2) is 33% deprotonated?

All of the amino acids EXCEPT ____ have both free α-amino and free α-carboxyl groups.

The pKa of the cysteine side chain ____ group is 8.32, so it is about 11% deprotonated at pH ____.

Discuss the side-chain groups of amino acids that undergo ionizations.​

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Completing the Protein Life Cycle: Folding, Processing, and Degradation

The Reception and Transmission of Extracellular Information

Filters

The amino acid with a side-chain pK_a near neutrality and which therefore plays an important role as proton donor and acceptor in many enzyme catalyzed reactions is:

Glutamic acid has pK_a values of 2.2, 4.3, and 9.7. Calculate the isoelectric point for glutamic acid.

Where Cα is the α-carbon, N represents the amide nitrogen and C_o is the carbonyl carbon of amino acids in a peptide, the peptide backbone of a protein consists of the repeated sequence:

What is the pH of a serine solution in which the α−amine group (pK_a 9.2) is 33% deprotonated?

The pK_a of the cysteine side chain group is 8.32, so it is about 11% deprotonated at pH .

Discuss the side-chain groups of amino acids that undergo ionizations.