Exam 4: Amino Acids and the Peptide Bond

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The amino and carboxyl groups of amino acids react in a head-to-tail fashion, eliminating water, and forming a covalent linkage typically referred to as a(n) bond.

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Question 1

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The intrinsic properties of the 20 amino acids include all EXCEPT:

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Question 2

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Explain the classification of peptides based on the number of amino acids they contain.

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Question 3

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Peptide is the name assigned to short polymers of amino acids. Peptides are classified according to the number of amino acid units in the chain. Each unit is called an amino acid residue, the word residue denoting what is left after the release of H₂O when an amino acid forms a peptide link upon joining the peptide chain. Dipeptides have two amino acid residues, tripeptides have three, tetrapeptides four, and so on. After about 12 residues, this terminology becomes cumbersome, so peptide chains of more than 12 and less than about 20 amino acid residues are usually referred to as oligopeptides, and when the chain exceeds several dozen amino acids in length, the term polypeptide is used. The distinctions in this terminology are not precise.

The difference between serine and homoserine is the same as between cysteine and homocysteine. This change from the common amino acid is:

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Question 4

All of the statements about the classification of these amino acids are correct EXCEPT:

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Question 5

All are true for stereoisomers EXCEPT:

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Question 6

Which of the listed amino acids is classified as a basic amino acid?

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Question 7

Which of the peptides would absorb light at 280 nm?

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Question 8

Discuss the principles on which methods of amino acid separation are based.

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Question 9

Discuss the amino acids that occur only rarely in proteins.

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Question 10

Which of the following amino acids absorbs light most strongly between 250 and 300 nm?

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Question 11

At which of the following pH values would histidine (pK_a values of 1.8, 6.0 and 9.2) be found with a net negative charge?

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Question 12

All are true statements about L-isoleucine EXCEPT:

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Question 13

If the pI of a peptide is 4.6, might be present while would probably be absent.

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Question 14

The pK_a of the α−carboxyl group of an amino acid is ____ by the presence on the amine group.

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Question 15

Which of the following IS NOT a result of resonance in peptide bonds?

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Question 16

Explain the chirality of amino acid molecules.

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Question 17

Which of the following amino acids has more than one chiral carbon?

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Question 18

Which of the following atoms IS NOT contained within the amide plane of the peptide backbone?

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Question 19

For the peptide Ala-His-Glu-Val-Asp-Cys-Lys-Leu, what is the net charge at pH 3?

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Question 20

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Exam 4: Amino Acids and the Peptide Bond

The amino and carboxyl groups of amino acids react in a head-to-tail fashion, eliminating water, and forming a covalent ____ linkage typically referred to as a(n) ____ bond.

The intrinsic properties of the 20 amino acids include all EXCEPT:

Explain the classification of peptides based on the number of amino acids they contain.​

The difference between serine and homoserine is the same as between cysteine and homocysteine. This change from the common amino acid is:

All of the statements about the classification of these amino acids are correct EXCEPT:

All are true for stereoisomers EXCEPT:

Which of the listed amino acids is classified as a basic amino acid?

Which of the peptides would absorb light at 280 nm?

Discuss the principles on which methods of amino acid separation are based.​

Discuss the amino acids that occur only rarely in proteins.​

Which of the following amino acids absorbs light most strongly between 250 and 300 nm?

At which of the following pH values would histidine (pKa values of 1.8, 6.0 and 9.2) be found with a net negative charge?

All are true statements about L-isoleucine EXCEPT:

If the pI of a peptide is 4.6, ____ might be present while ____ would probably be absent.

The pKa of the α−carboxyl group of an amino acid is ____ by the presence on the amine group.

Which of the following IS NOT a result of resonance in peptide bonds?

Explain the chirality of amino acid molecules.​

Which of the following amino acids has more than one chiral carbon?

Which of the following atoms IS NOT contained within the amide plane of the peptide backbone?

For the peptide Ala-His-Glu-Val-Asp-Cys-Lys-Leu, what is the net charge at pH 3?

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 and carboxyl groups of amino acids react in a head-to-tail fashion, eliminating water, and forming a covalent linkage typically referred to as a(n) bond.

Explain the classification of peptides based on the number of amino acids they contain.

Discuss the principles on which methods of amino acid separation are based.

Discuss the amino acids that occur only rarely in proteins.

At which of the following pH values would histidine (pK_a values of 1.8, 6.0 and 9.2) be found with a net negative charge?

If the pI of a peptide is 4.6, might be present while would probably be absent.

The pK_a of the α−carboxyl group of an amino acid is ____ by the presence on the amine group.

Explain the chirality of amino acid molecules.