Question 1

Draw the Fischer projection for D-serine and assign the configuration (R/S) at the chirality center.

Accepted Answer

The answer of Draw the Fischer projection for D-serine and...

Question 2

Which of the following is the predominant form of lysine at pH 14?

Accepted Answer

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

Question 3

Proteins that consist of linear polypeptide chains bundled together are classified as________.

Accepted Answer

A)  globular proteins 
B)  fibrous proteins 
C)  lipoproteins 
D)  tetrapeptides 
E)  pleated sheets 
A)  globular proteins 
B)  fibrous proteins 
C)  lipoproteins 
D)  tetrapeptides 
E)  pleated sheets B

Question 4

Which of the following is true about the amino acids with isoelectric point around pH 3?

Accepted Answer

A)  The side chain must be acidic. 
B)  The side chain must be basic. 
C)  The side chain must be polar. 
D)  The side chain must be non polar. 
E)  none of these 
A)  The side chain must be acidic. 
B)  The side chain must be basic. 
C)  The side chain must be polar. 
D)  The side chain must be non polar. 
E)  none of these

Question 5

Separation of amino acids using electrophoresis is mainly based on ______.

Accepted Answer

A)  differences in the pI values 
B)  concentration 
C)  differences in pH values 
D)  none of these 
A)  differences in the pI values 
B)  concentration 
C)  differences in pH values 
D)  none of these

Question 6

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 7

List the reason why the s-trans conformation of a peptide bond is more stable than the s-cis conformation.

Accepted Answer

A)  there is a restricted rotation around the peptide bond 
B)  rotation is allowed around the peptide bond 
C)  it has reduced steric hindrance 
D)  none of these 
A)  there is a restricted rotation around the peptide bond 
B)  rotation is allowed around the peptide bond 
C)  it has reduced steric hindrance 
D)  none of these

Question 8

Hemoglobin, found in blood, is classified as a ______ protein.

Accepted Answer

A)  structural 
B)  regulatory 
C)  transport 
D)  fibrous 
E)  globular 
A)  structural 
B)  regulatory 
C)  transport 
D)  fibrous 
E)  globular

Question 9

Which of the following reagents is used to protect the amino group in the selective synthesis of the dipeptide Ala-Val?

Accepted Answer

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

Question 10

Which of the following amino acids is achiral?

Accepted Answer

A)  alanine 
B)  leucine 
C)  glycine 
D)  phenylalanine 
E)  none of these 
A)  alanine 
B)  leucine 
C)  glycine 
D)  phenylalanine 
E)  none of these

Question 11

Which of the following fragments are formed when the following peptide is cleaved using chymotrypsin? Gly-Lys-Cys-Phe-Ile-Val-Tyr-Ala-Ser

Accepted Answer

A)  Gly-Lys-Cys, Phe-Ile-Val, Tyr-Ala-Ser 
B)  Gly-Lys-Cys-Phe, Ile-Val-Tyr, Ala-Ser 
C)  Gly-Lys-Cys-Phe, Ile-Val, Tyr-Ala-Ser 
D)  Gly-Lys-Cys, Phe, Ile-Val-Tyr, Ala-Ser 
E)  Gly-Lys, Cys-Phe, Ile-Val-Tyr-Ala-Ser 
A)  Gly-Lys-Cys, Phe-Ile-Val, Tyr-Ala-Ser 
B)  Gly-Lys-Cys-Phe, Ile-Val-Tyr, Ala-Ser 
C)  Gly-Lys-Cys-Phe, Ile-Val, Tyr-Ala-Ser 
D)  Gly-Lys-Cys, Phe, Ile-Val-Tyr, Ala-Ser 
E)  Gly-Lys, Cys-Phe, Ile-Val-Tyr-Ala-Ser

Question 12

What is the pI of the following amino acid?

Accepted Answer

A)  1.16 
B)  4.81 
C)  5.97 
D)  9.62 
E)  none of these 
A)  1.16 
B)  4.81 
C)  5.97 
D)  9.62 
E)  none of these

Question 13

Which of the following is the predominant form of aspartic acid at pH 1?

Accepted Answer

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

Question 14

In $\alpha$-amino acids the amino and carboxylic acid groups are separated by ____,

Accepted Answer

A)  two carbon atoms 
B)  one carbon atom 
C)  peptide linkage 
D)  amide linkage 
E)  none of these 
A)  two carbon atoms 
B)  one carbon atom 
C)  peptide linkage 
D)  amide linkage 
E)  none of these

Question 15

Which amino acid is produced from the following reaction?

Accepted Answer

A)  methionine 
B)  serine 
C)  cysteine 
D)  lysine 
E)  none of these 
A)  methionine 
B)  serine 
C)  cysteine 
D)  lysine 
E)  none of these

Question 16

The heme group present in hemoglobin is called a _______.

Accepted Answer

A)  prosthetic group 
B)  substrate 
C)  cofactor 
D)  byfactor 
E)  enzyme 
A)  prosthetic group 
B)  substrate 
C)  cofactor 
D)  byfactor 
E)  enzyme

Question 17

Which of the following tetrapeptides is not cleaved by chymotrypsin?

Accepted Answer

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

Question 18

Provide the structure of the predominant form of alanine at pH 2?

Accepted Answer

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

Question 19

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

Accepted Answer

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

Question 20

Provide the reagents necessary to prepare phenylalanine using a Strecker synthesis.

Accepted Answer

The answer of Provide the reagents necessary to prepare phenylalanine...

Exam 25: Amino Acids, Peptides, and Proteins

Draw the Fischer projection for D-serine and assign the configuration (R/S) at the chirality center.

Which of the following is the predominant form of lysine at pH 14?

Proteins that consist of linear polypeptide chains bundled together are classified as________.

Which of the following is true about the amino acids with isoelectric point around pH 3?

Separation of amino acids using electrophoresis is mainly based on ______.

Which amino acid is produced from the following reaction sequence?

List the reason why the s-trans conformation of a peptide bond is more stable than the s-cis conformation.

Hemoglobin, found in blood, is classified as a ______ protein.

Which of the following reagents is used to protect the amino group in the selective synthesis of the dipeptide Ala-Val?

Which of the following amino acids is achiral?

Which of the following fragments are formed when the following peptide is cleaved using chymotrypsin? Gly-Lys-Cys-Phe-Ile-Val-Tyr-Ala-Ser

What is the pI of the following amino acid?

Which of the following is the predominant form of aspartic acid at pH 1?

In α\alphaα -amino acids the amino and carboxylic acid groups are separated by ____,

Which amino acid is produced from the following reaction?

The heme group present in hemoglobin is called a _______.

Which of the following tetrapeptides is not cleaved by chymotrypsin?

Provide the structure of the predominant form of alanine at pH 2?

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

Provide the reagents necessary to prepare phenylalanine using a Strecker synthesis.

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

In $\alpha$ -amino acids the amino and carboxylic acid groups are separated by ____,