Question 1

What is the major organic product for the following reaction?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D A

Question 2

Which of the following is (are)globular protein(s)?

Accepted Answer

A) Hemoglobin 
B) Keratins 
C) Collagens 
D) Elastins 
A) Hemoglobin 
B) Keratins 
C) Collagens 
D) Elastins A

Question 3

Why is the s-trans form of an amide bond more stable?

Accepted Answer

A) There is no s-cis form in an amide bond. 
B) The oxygen is hydrogen-bonded with the nitrogen atom. 
C) The nitrogen is able to be sp2-hybridized. 
D) The more sterically bulky groups are farther apart. 
A) There is no s-cis form in an amide bond. 
B) The oxygen is hydrogen-bonded with the nitrogen atom. 
C) The nitrogen is able to be sp2-hybridized. 
D) The more sterically bulky groups are farther apart. D

Question 4

What is the major organic product for the following reaction?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 5

Which of the following amino acids does not have an L-isomer?

Accepted Answer

A) Alanine 
B) Valine 
C) Glycine 
D) Leucine 
A) Alanine 
B) Valine 
C) Glycine 
D) Leucine

Question 6

What is the product of the following reaction? (Assume workup to neutralize.)

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 7

Which of the following compounds is not an amino acid?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 8

Which of the following amino acids is achiral?

Accepted Answer

A) Phenylalanine 
B) Glycine 
C) Valine 
D) Alanine 
A) Phenylalanine 
B) Glycine 
C) Valine 
D) Alanine

Question 9

Which of the following is the major advantage of the Merrifield synthesis of peptides?

Accepted Answer

A) It allows for the formation of absolutely no by-products. 
B) Impurities can be easily washed away. 
C) Excess reagent can be used. 
D) It prevents hydrogenation. 
A) It allows for the formation of absolutely no by-products. 
B) Impurities can be easily washed away. 
C) Excess reagent can be used. 
D) It prevents hydrogenation.

Question 10

Which is the correct structure for the amino acid valine?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 11

Which of the following correctly describes the Merrifield synthesis?

Accepted Answer

A) It uses a solid phase technique for the synthesis of peptides. 
B) It uses DCC (dicyclohexylcarbodiimide)to form the amide bond in a peptide synthesis. 
C) It uses BOC (tert-butoxycarbonyl)as a protecting group for peptide synthesis. 
D) It uses aqueous phase techniques for the synthesis of large polypeptides. 
A) It uses a solid phase technique for the synthesis of peptides. 
B) It uses DCC (dicyclohexylcarbodiimide)to form the amide bond in a peptide synthesis. 
C) It uses BOC (tert-butoxycarbonyl)as a protecting group for peptide synthesis. 
D) It uses aqueous phase techniques for the synthesis of large polypeptides.

Question 12

What is the configuration of naturally occurring amino acids?

Accepted Answer

A) D 
B) S 
C) L 
D) R 
A) D 
B) S 
C) L 
D) R

Question 13

What reagents would you use to convert acetaldehyde into alanine?

Accepted Answer

A) NH3 
B) HCN 
C) NaCN,NH4Cl 
D) NaNH2 
A) NH3 
B) HCN 
C) NaCN,NH4Cl 
D) NaNH2

Question 14

Give the order (1st to last)in which the following amino acids would be eluted with a buffer of pH = 4 from a column containing a cationic-exchange resin (Dowex 50): Arg (pI = 10.8),Ser (pI = 5.7),Asp (pI = 2.8)and His (pI = 7.6).

Accepted Answer

A) His,Ser,Asp,Arg 
B) Arg,His,Ser,Asp 
C) His,Ser,Arg,Asp 
D) Asp,Ser,His,Arg 
A) His,Ser,Asp,Arg 
B) Arg,His,Ser,Asp 
C) His,Ser,Arg,Asp 
D) Asp,Ser,His,Arg

Question 15

Why do amide bonds exist as reasonably stable s-cis or s-trans isomers at room temperature?

Accepted Answer

A) These amide bonds are not stable. 
B) There is partial double bond character between the carbonyl carbon and the nitrogen atom. 
C) The oxygen atom is hydrogen-bonded with the nitrogen atom. 
D) The side-chains can form hydrogen bonds. 
A) These amide bonds are not stable. 
B) There is partial double bond character between the carbonyl carbon and the nitrogen atom. 
C) The oxygen atom is hydrogen-bonded with the nitrogen atom. 
D) The side-chains can form hydrogen bonds.

Question 16

Which of the following is (are)fibrous protein(s)?

Accepted Answer

A) Keratins 
B) Hormones 
C) Enzymes 
D) Antibodies 
A) Keratins 
B) Hormones 
C) Enzymes 
D) Antibodies

Question 17

Below is a 2D chromatogram that shows the separation of five amino acids.In this technique,the amino acid mixture is first separated by chromatography using a polar solvent system.Then the plate is rotated 90°,and the amino acids are further separated by electrophoresis.Identify the spots obtained from a mixture of Trp,Glu,Lys,Ile and Thr.A table with isoelectric points is included to aid in solving this problem.   amino acid-pI value Trp-5.9
Glu-3.2
Lys-9.7
Ile-6.0
Thr-5.6

Accepted Answer

A) 1=Lys,2=Thr,3=Glu,4=Trp,5=Ile 
B) 1=Glu,2=Thr,3=Lys,4=Trp,5=Ile 
C) 1=Lys,2=Ile,3=Glu,4=Trp,5=Thr 
D) 1=Glu,2=Ile,3=Lys,4=Trp,5=Thr 
A) 1=Lys,2=Thr,3=Glu,4=Trp,5=Ile 
B) 1=Glu,2=Thr,3=Lys,4=Trp,5=Ile 
C) 1=Lys,2=Ile,3=Glu,4=Trp,5=Thr 
D) 1=Glu,2=Ile,3=Lys,4=Trp,5=Thr

Question 18

What is the product of the following reaction? (Assume workup to neutralize.)

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 19

Which of the following correctly describes the tertiary structure of a peptide?

Accepted Answer

A) the three-dimensional conformations of localized regions of a protein 
B) the particular sequence of amino acids that are joined together by peptide bonds 
C) the structure is defined by the b-pleated sheet form 
D) the three-dimensional shape adopted by the entire peptide 
A) the three-dimensional conformations of localized regions of a protein 
B) the particular sequence of amino acids that are joined together by peptide bonds 
C) the structure is defined by the b-pleated sheet form 
D) the three-dimensional shape adopted by the entire peptide

Question 20

Which of the following aldehydes would be a good starting material in the Strecker synthesis of phenylalanine?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Exam 27: Amino Acids and Proteins

What is the major organic product for the following reaction?

Which of the following is (are)globular protein(s)?

Why is the s-trans form of an amide bond more stable?

What is the major organic product for the following reaction?

Which of the following amino acids does not have an L-isomer?

What is the product of the following reaction? (Assume workup to neutralize.)

Which of the following compounds is not an amino acid?

Which of the following amino acids is achiral?

Which of the following is the major advantage of the Merrifield synthesis of peptides?

Which is the correct structure for the amino acid valine?

Which of the following correctly describes the Merrifield synthesis?

What is the configuration of naturally occurring amino acids?

What reagents would you use to convert acetaldehyde into alanine?

Give the order (1st to last)in which the following amino acids would be eluted with a buffer of pH = 4 from a column containing a cationic-exchange resin (Dowex 50): Arg (pI = 10.8),Ser (pI = 5.7),Asp (pI = 2.8)and His (pI = 7.6).

Why do amide bonds exist as reasonably stable s-cis or s-trans isomers at room temperature?

Which of the following is (are)fibrous protein(s)?

What is the product of the following reaction? (Assume workup to neutralize.)

Which of the following correctly describes the tertiary structure of a peptide?

Which of the following aldehydes would be a good starting material in the Strecker synthesis of phenylalanine?

Structure and Bonding

Acids and Bases

Introduction to Organic Molecules and Functional Groups

Alkanes

Stereochemistry

Understanding Organic Reactions

Alkyl Halides and Nucleophilic Substitution

Alkyl Halides and Elimination Reactions

Alcohols,ethers,and Related Compounds

Alkenes and Addition Reactions

Alkynes and Synthesis

Oxidation and Reduction

Radical Reactions

Conjugation, resonance, and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation and Reduction

Aldehydes and Ketones - Nucleophilic Addition

Carboxylic Acids and the Acidity of the O-H Bond

Carboxylic Acids and Their Derivatives - Nucleophilic Acyl Substitution

Substitution Reactions of Carbonyl Compounds at the a Carbon

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond-Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Synthetic Polymers

Lipids

Molecular Ion Peaks and Fragmentation Patterns

Analyzing Molecular Motion and Infrared Spectroscopy

Organic Spectroscopy Concepts

Filters

Give the order (1^st to last)in which the following amino acids would be eluted with a buffer of pH = 4 from a column containing a cationic-exchange resin (Dowex 50): Arg (pI = 10.8),Ser (pI = 5.7),Asp (pI = 2.8)and His (pI = 7.6).