Question 1

How many different amino acids are abundantly found in proteins?

Accepted Answer

A)  10 
B)  16 
C)  20 
D)  40 
E)  none of these 
A)  10 
B)  16 
C)  20 
D)  40 
E)  none of these

Question 2

How will you prepare glycine staring with ethanol and using a Hell-Volhard-Zelinski reaction?

Accepted Answer

@#IMG-DLM&_TB4454_00

Question 3

When four amino acids are connected to each other, they form ____________.

Accepted Answer

A)  a tripeptide 
B)  a protein 
C)  a polypeptide 
D)  a tetrapeptide 
E)  a dipeptide 
A)  a tripeptide 
B)  a protein 
C)  a polypeptide 
D)  a tetrapeptide 
E)  a dipeptide

Question 4

Provide a stepwise synthesis for the dipeptide Ser-Phe.

Accepted Answer

@#IMG-DLM&_TB4454_00 @#IMG-DLM&_TB4454_0

Question 5

When two amino acids are connected to each other, they form ____________.

Accepted Answer

A)  a tripeptide 
B)  a protein 
C)  a polypeptide 
D)  a tetrapeptide 
E)  a dipeptide 
A)  a tripeptide 
B)  a protein 
C)  a polypeptide 
D)  a tetrapeptide 
E)  a dipeptide

Question 6

Provide the structure of the predominant form of the following amino acids at pH 6 and predict the migration towards anode or cathode during electrophoresis.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 7

Which of the following dipeptides is formed when leucine is treated with (BoC)2O and glycine is treated with benzyl alcohol/acid first and the resulting intermediates are reacted in the presence of DCC followed by treatment with trifluoroacetic acid and then aqueous NaOH?

Accepted Answer

A)  Gly-Leu 
B)  Gly-Gly 
C)  Leu-Gly 
D)  Leu-Leu 
E)  all of these 
A)  Gly-Leu 
B)  Gly-Gly 
C)  Leu-Gly 
D)  Leu-Leu 
E)  all of these

Question 8

Cooking an egg is an example of ________________, and is irreversible.

Accepted Answer

The answer of Cooking an egg is an example of...

Question 9

Hydrogen bonding between the carbonyl group of an amino acid on one strand with the amino group of the neighboring strand leads to ______.

Accepted Answer

A)  parallel $\beta$-pleated sheets 
B)  antiparallel $\beta$-pleated sheets 
C)  an $\alpha$-helix 
D)  a $\beta$-helix 
E)  either A or B 
A)  parallel $\beta$-pleated sheets 
B)  antiparallel $\beta$-pleated sheets 
C)  an $\alpha$-helix 
D)  a $\beta$-helix 
E)  either A or B

Question 10

Which of the following tetrapeptides is not cleaved by trypsin?

Accepted Answer

A)  Gly-Lys-Cys-Phe 
B)  Cys-Ala-Arg-Ser 
C)  Gly-Ser-Ile-Lys 
D)  Ala-Lys-Tyr-Arg 
E)  Lys-Met-Pro-Ala 
A)  Gly-Lys-Cys-Phe 
B)  Cys-Ala-Arg-Ser 
C)  Gly-Ser-Ile-Lys 
D)  Ala-Lys-Tyr-Arg 
E)  Lys-Met-Pro-Ala

Question 11

Provide the structure of the predominant form of valine at pH 10?

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 12

Which amino acid is produced from the following reaction sequence?

Accepted Answer

A)  alanine 
B)  valine 
C)  leucine 
D)  isoleucine 
E)  none of these 
A)  alanine 
B)  valine 
C)  leucine 
D)  isoleucine 
E)  none of these

Question 13

Which amino acid is produced from the following reaction sequence?

Accepted Answer

A)  alanine 
B)  valine 
C)  leucine 
D)  isoleucine 
E)  none of these 
A)  alanine 
B)  valine 
C)  leucine 
D)  isoleucine 
E)  none of these

Question 14

Which of the following amino acids have a pI around pH 3?

Accepted Answer

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

Question 15

Provide the structure of the amino acid produced from the following reaction.

Accepted Answer

The answer of Provide the structure of the amino acid...

Question 16

The quaternary structure of a protein is due to _______.

Accepted Answer

A)  hydrogen bonding within the peptide 
B)  aggregation of two or more polypeptides 
C)  disulfide linkages within the peptide 
D)  covalent bonding between peptides 
A)  hydrogen bonding within the peptide 
B)  aggregation of two or more polypeptides 
C)  disulfide linkages within the peptide 
D)  covalent bonding between peptides

Question 17

Identify the compound that reacts with amino acids to form a fluorescent purple product.

Accepted Answer

A)  2,4-DNP 
B)  ninhydrin 
C)  methyl orange 
D)  methyl red 
E)  phenolphthalein 
A)  2,4-DNP 
B)  ninhydrin 
C)  methyl orange 
D)  methyl red 
E)  phenolphthalein

Question 18

Which of the following reagent(s) is(are) used to remove the N-terminus amino acid residue using Edman degradation?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  none of these 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  none of these

Question 19

Edman degradation removes one amino acid residue at a time from the _______ of the peptide.

Accepted Answer

A)  C-terminus 
B)  N-terminus 
C)  middle 
D)  none of these 
A)  C-terminus 
B)  N-terminus 
C)  middle 
D)  none of these

Question 20

Identify how disulfide bonds are formed.

Accepted Answer

A)  oxidation of thiol groups 
B)  joining cysteine residues within a peptide 
C)  joining cysteine residues between two strands of a peptide 
D)  all of these 
A)  oxidation of thiol groups 
B)  joining cysteine residues within a peptide 
C)  joining cysteine residues between two strands of a peptide 
D)  all of these

Exam 25: Amino Acids, Peptides, and Proteins

How many different amino acids are abundantly found in proteins?

How will you prepare glycine staring with ethanol and using a Hell-Volhard-Zelinski reaction?

When four amino acids are connected to each other, they form ____________.

Provide a stepwise synthesis for the dipeptide Ser-Phe.

When two amino acids are connected to each other, they form ____________.

Provide the structure of the predominant form of the following amino acids at pH 6 and predict the migration towards anode or cathode during electrophoresis.

Which of the following dipeptides is formed when leucine is treated with (BoC)2O and glycine is treated with benzyl alcohol/acid first and the resulting intermediates are reacted in the presence of DCC followed by treatment with trifluoroacetic acid and then aqueous NaOH?

Cooking an egg is an example of ________________, and is irreversible.

Hydrogen bonding between the carbonyl group of an amino acid on one strand with the amino group of the neighboring strand leads to ______.

Which of the following tetrapeptides is not cleaved by trypsin?

Provide the structure of the predominant form of valine at pH 10?

Which amino acid is produced from the following reaction sequence?

Which amino acid is produced from the following reaction sequence?

Which of the following amino acids have a pI around pH 3?

Provide the structure of the amino acid produced from the following reaction.

The quaternary structure of a protein is due to _______.

Identify the compound that reacts with amino acids to form a fluorescent purple product.

Which of the following reagent(s) is(are) used to remove the N-terminus amino acid residue using Edman degradation?

Edman degradation removes one amino acid residue at a time from the _______ of the peptide.

Identify how disulfide bonds are formed.

A Review of General Chemistry: Electrons, Bonds, and Molecular Properties

Molecular Representations

Acids and Bases

Alkanes and Cycloalkanes

Stereoisomerism

Chemical Reactivity and Mechanisms

Alkyl Halides: Nucleophilic Substitution and Elimination Reactions

Addition Reactions of Alkenes

Alkynes

Radical Reactions

Synthesis

Alcohols and Phenols

Ethers and Epoxides; Thiols and Sulfides

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Conjugated Pi Systems and Pericyclic Reactions

Aromatic Compounds

Aromatic Substitution Reactions

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Alpha Carbon Chemistry: Enols and Enolates

Amines

Introduction to Organometallic Compounds

Carbohydrates

Lipids

Synthetic Polymers

Filters

Which of the following dipeptides is formed when leucine is treated with (BoC)₂O and glycine is treated with benzyl alcohol/acid first and the resulting intermediates are reacted in the presence of DCC followed by treatment with trifluoroacetic acid and then aqueous NaOH?