Question 1

The peptide hormone insulin is composed of two peptide held together primarily by what mechanism?

Accepted Answer

A) disulfide bonds between cysteine residues 
B) charge-charge interactions between acidic and basic amino acids 
C) extensive hydrogen bonding due to the relatively high serine and glutamine content 
D) hydrophobic interactions 
E) an amide bond formed from the R-groups of a glutamic acid residue and a lysine residue 
A) disulfide bonds between cysteine residues 
B) charge-charge interactions between acidic and basic amino acids 
C) extensive hydrogen bonding due to the relatively high serine and glutamine content 
D) hydrophobic interactions 
E) an amide bond formed from the R-groups of a glutamic acid residue and a lysine residue A

Question 2

What is the pI for the following peptide: Ala-Glu-Val-Asp-Lys-Leu

Accepted Answer

Use R-groups of Glu and Asp: (4.2 + 3.9)/2 = 4.05 (4.1 using correct SF)

Question 3

Given the following peptide,what pair of protease enzymes would be able to produce three smaller peptides?

Gly-Ser-Ala-His-Phe-Pro-Asn-Ala-Val-Glu-Cys-Ala-Ser

Accepted Answer

A) chymotrypsin and thrombin 
B) trypsin and chymotrypsin 
C) thermolysin and chymotrypsin 
D) trypsin and thermolysin 
E) none of the above 
A) chymotrypsin and thrombin 
B) trypsin and chymotrypsin 
C) thermolysin and chymotrypsin 
D) trypsin and thermolysin 
E) none of the above C

Question 4

Which of the following pairs of amino acids could form a charge-charge interaction through their R-groups?

Accepted Answer

A) methionine and histidine 
B) glutamine and lysine 
C) serine and glutamic acid 
D) aspartic acid and arginine 
E) threonine and asparagine 
A) methionine and histidine 
B) glutamine and lysine 
C) serine and glutamic acid 
D) aspartic acid and arginine 
E) threonine and asparagine

Question 5

Draw each of the structures of aspartic acid that predominate at pH 1,3,7,and 11.

Accepted Answer

The answer of Draw each of the structures of aspartic...

Question 6

What is the sequence of the following peptide?

Accepted Answer

A) Ile-Ala-Glu 
B) Val-Ala-Asp 
C) Leu-Gly-Glu 
D) Val-Ala-Asn 
E) Val-Gly-Gln 
A) Ile-Ala-Glu 
B) Val-Ala-Asp 
C) Leu-Gly-Glu 
D) Val-Ala-Asn 
E) Val-Gly-Gln

Question 7

The conversion of ________ represents a conservative change while the conversion of ________ represents a nonconservative change.

Accepted Answer

A) Asp to Arg;Ile to Ser 
B) Tyr to Phe;Lys to Arg 
C) Gln to Asn;Ser to Thr 
D) Ile to Leu;Asn to Ala 
E) Cys to His;Lys to Glu 
A) Asp to Arg;Ile to Ser 
B) Tyr to Phe;Lys to Arg 
C) Gln to Asn;Ser to Thr 
D) Ile to Leu;Asn to Ala 
E) Cys to His;Lys to Glu

Question 8

A peptide was treated with protease enzymes and cyanogen bromide followed by complete hydrolysis of the resulting products.Based upon the following data,determine the sequence of the original peptide.

Chymotrypsin gave two peptides containing the following amino acids:
Leu,Pro
Asp,Gln,Arg,Met,Tyr,Val

Cyanogen bromide gave two peptides containing the following amino acids:
Asp,Met
Gln,Leu,Arg,Tyr,Pro,Val

Trypsin gave two peptides containing the following amino acids:
Gln,Leu,Tyr,Pro
Asp,Arg,Met,Val

Accepted Answer

Chymotrypsin treatment shows the C-term

Question 9

Which of the following pairs of amino acids could form a hydrogen bond through their R-groups?

Accepted Answer

A) serine and phenylalanine 
B) aspartic acid and methionine 
C) histidine and tyrosine 
D) alanine and glutamine 
E) leucine and cysteine 
A) serine and phenylalanine 
B) aspartic acid and methionine 
C) histidine and tyrosine 
D) alanine and glutamine 
E) leucine and cysteine

Question 10

Which of the following events occurs after the formation of disulfide bonds during the conversion of preproinsulin to mature insulin?

Accepted Answer

A) folding of proinsulin into a stable conformation 
B) transport of the molecule through the membranes 
C) cleavage of the peptide sequence that joins the A and B chains 
D) cleavage of the leader sequence 
E) posttranslational modification of specific proline residues 
A) folding of proinsulin into a stable conformation 
B) transport of the molecule through the membranes 
C) cleavage of the peptide sequence that joins the A and B chains 
D) cleavage of the leader sequence 
E) posttranslational modification of specific proline residues

Question 11

Which of the following amino acids is incorporated into proteins during ribosomal protein synthesis?

Accepted Answer

A) sarcosine 
B) ornithine 
C) 4-hydroxyproline 
D) phosphoserine 
E) selenocysteine 
A) sarcosine 
B) ornithine 
C) 4-hydroxyproline 
D) phosphoserine 
E) selenocysteine

Question 12

Which of the following pairs of amino acids represents a conservation of the type of amino acid when considering the sequence of a protein from different species?

Accepted Answer

A) Asp and Asn 
B) Lys and His 
C) Leu and Val 
D) Gly and Ile 
E) Phe and Trp 
A) Asp and Asn 
B) Lys and His 
C) Leu and Val 
D) Gly and Ile 
E) Phe and Trp

Question 13

Which of the following undergoes an oxidation reaction to form a disulfide bond?

Accepted Answer

A) serine 
B) cysteine 
C) methionine 
D) threonine 
E) tyrosine 
A) serine 
B) cysteine 
C) methionine 
D) threonine 
E) tyrosine

Question 14

At physiological pH,most amino acids are _______,meaning that they contain both a positive and negative charge.

Accepted Answer

A) zwitterions 
B) amphoteric 
C) chiral 
D) amphipathic 
E) none of the above 
A) zwitterions 
B) amphoteric 
C) chiral 
D) amphipathic 
E) none of the above

Question 15

Which of the following amino acids is derived from another amino acid by the addition of an amine group?

Accepted Answer

A) lysine 
B) asparagine 
C) arginine 
D) histidine 
E) none of the above 
A) lysine 
B) asparagine 
C) arginine 
D) histidine 
E) none of the above

Question 16

If a cis peptide bond is found in a protein,the most likely amino acid to contribute the amine to the amide bond is ______.

Accepted Answer

A) phenylalanine 
B) leucine 
C) proline 
D) glycine 
E) arginine 
A) phenylalanine 
B) leucine 
C) proline 
D) glycine 
E) arginine

Question 17

The prevalence of the trans orientation in peptide bonds results in the R-groups of adjacent amino acids being oriented approximately ______ degrees with respect to each other.

Accepted Answer

A) 30 
B) 60 
C) 90 
D) 120 
E) 180 
A) 30 
B) 60 
C) 90 
D) 120 
E) 180

Question 18

Given the following peptide,what would be the overall charge at pH 5?

Met-Glu-Ser-Arg-His-Phe-Pro-Asn-Ala-Glu-Cys-Ala-Ser

Accepted Answer

A) +2 
B) +1 
C) 0 
D) -1 
E) -2 
A) +2 
B) +1 
C) 0 
D) -1 
E) -2

Question 19

Which of the following bonds has partial double bond character?

Accepted Answer

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

Question 20

Of the following amino acids,which will have a pI closest to 3?

Accepted Answer

A) Cys 
B) His 
C) Gly 
D) Asp 
E) Lys 
A) Cys 
B) His 
C) Gly 
D) Asp 
E) Lys

Exam 5: Introduction to Proteins: the Primary Level of Protein Structure

The peptide hormone insulin is composed of two peptide held together primarily by what mechanism?

What is the pI for the following peptide: Ala-Glu-Val-Asp-Lys-Leu

Given the following peptide,what pair of protease enzymes would be able to produce three smaller peptides? Gly-Ser-Ala-His-Phe-Pro-Asn-Ala-Val-Glu-Cys-Ala-Ser

Which of the following pairs of amino acids could form a charge-charge interaction through their R-groups?

Draw each of the structures of aspartic acid that predominate at pH 1,3,7,and 11.

What is the sequence of the following peptide?

The conversion of ________ represents a conservative change while the conversion of ________ represents a nonconservative change.

Which of the following pairs of amino acids could form a hydrogen bond through their R-groups?

Which of the following events occurs after the formation of disulfide bonds during the conversion of preproinsulin to mature insulin?

Which of the following amino acids is incorporated into proteins during ribosomal protein synthesis?

Which of the following pairs of amino acids represents a conservation of the type of amino acid when considering the sequence of a protein from different species?

Which of the following undergoes an oxidation reaction to form a disulfide bond?

At physiological pH,most amino acids are _______,meaning that they contain both a positive and negative charge.

Which of the following amino acids is derived from another amino acid by the addition of an amine group?

If a cis peptide bond is found in a protein,the most likely amino acid to contribute the amine to the amide bond is ______.

The prevalence of the trans orientation in peptide bonds results in the R-groups of adjacent amino acids being oriented approximately ______ degrees with respect to each other.

Given the following peptide,what would be the overall charge at pH 5? Met-Glu-Ser-Arg-His-Phe-Pro-Asn-Ala-Glu-Cys-Ala-Ser

Which of the following bonds has partial double bond character?

Of the following amino acids,which will have a pI closest to 3?

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

The Three-Dimensional Structure of Proteins

Protein Function and Evolution

Contractile Proteins and Molecular Motors

Carbohydrates: Sugars,saccharides,glycans

Lipids,membranes and Cellular Transport

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism I: Fatty Acids,triacylglycerols,and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, steroids, isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, utilization, and Turnover

Metabolism of Nitogenous Compounds Ii: Amino Acids, porphyrins, and Neurotransmitters

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes,genomes and Chromosomes

Dna Replication

Dna Restructuring: Repair,recombination,rearrangement,amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters

The conversion of represents a conservative change while the conversion of represents a nonconservative change.