Amino Acids and Peptides 25
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Questions and Answers

Proteins and many other important biomolecules are made from nucleic acids.

False

Glycine is the only achiral member of the 20 common amino acids.

True

All amino acids exist as the L-optical form in Nature.

True

Amino acids contain only an acid, but not a base.

<p>False</p> Signup and view all the answers

Aromatic Amino Acids are crucial for the visualization of proteins.

<p>True</p> Signup and view all the answers

Oligopeptides contain 2-10 amino acids.

<p>True</p> Signup and view all the answers

Proteins generally contain between 50-400 residues.

<p>True</p> Signup and view all the answers

Peptide bonds have weak Resonance.

<p>False</p> Signup and view all the answers

A Tetrapeptide starts at the C-terminal AA.

<p>False</p> Signup and view all the answers

Cysteines can be linked via disulphide bonds.

<p>True</p> Signup and view all the answers

Glutathione contains Glu-Cys-Gly linked via sidechain Glu acid.

<p>True</p> Signup and view all the answers

Insulin is made from a single chain of amino acids.

<p>False</p> Signup and view all the answers

Polyacrylamide gel electrophoresis (PAGE) is used for the purification of DNA.

<p>False</p> Signup and view all the answers

Isoelectric points are not important for the characterization and separation of amino acids, peptides, and proteins.

<p>False</p> Signup and view all the answers

Short chains of AA are oligopeptides, and larger chains are known as polypeptides.

<p>True</p> Signup and view all the answers

Peptide linkages are the only way amino acids can be linked together to produce amides.

<p>False</p> Signup and view all the answers

Which type of amino acid is commonly found in nature?

<p>α-amino acids</p> Signup and view all the answers

Which amino acid is the only achiral member of the 20 common amino acids?

<p>Glycine</p> Signup and view all the answers

What type of linkages can cysteines form?

<p>Disulfide bonds</p> Signup and view all the answers

Which book is recommended for the study of Amino Acids & Peptides?

<p>Bruice: “Organic Chemistry”, 4th Ed. Chapters 23 + 24</p> Signup and view all the answers

What is the characteristic of the isoelectric point for neutral amino acid side chains?

<p>It is equal to the average of the pKaCOOH and pKaNH3+.</p> Signup and view all the answers

Which suffix is used for oligopeptides containing 2-10 amino acids?

<p>Tri</p> Signup and view all the answers

What stabilizes peptide bonds by delocalization energy?

<p>Resonance</p> Signup and view all the answers

What is the name of the tetrapeptide shown in the image?

<p>Alanylleucine</p> Signup and view all the answers

Which peptide is involved in pain control?

<p>Methionine enkephalin</p> Signup and view all the answers

How are cysteines linked in glutathione?

<p>Via disulphide bonds</p> Signup and view all the answers

What is insulin made from?

<p>Single chain of amino acids</p> Signup and view all the answers

What is used to denature proteins into uniform rods in polyacrylamide gel electrophoresis (PAGE)?

<p>Sodium dodecyl sulphate (SDS)</p> Signup and view all the answers

What does the pH electrophoresis profile indicate?

<p>Charge of proteins</p> Signup and view all the answers

What does the term 'isolectric point' refer to?

<p>Maximum pH at which a molecule carries no net electrical charge.</p> Signup and view all the answers

What do short chains of amino acids form when linked together by peptide bonds?

<p>Oligopeptides</p> Signup and view all the answers

What is the suffix used for polypeptides with between 10-50 residues?

<p>Hexa</p> Signup and view all the answers

What is the characteristic of glycine among the 20 common amino acids?

<p>achiral</p> Signup and view all the answers

What type of amino acids are most commonly found in nature?

<p>a-amino acids</p> Signup and view all the answers

What is the recommended book for the study of Amino Acids & Peptides?

<p>Bruice: “Organic Chemistry”, 4th Ed. Chapters 23 + 24</p> Signup and view all the answers

What is the only amino acid that exists as the L-optical form?

<p>glycine</p> Signup and view all the answers

What is the characteristic isoelectric point for neutral amino acid side chains?

<p>pI = 1/2 (pKaCOOH+pKaNH3+)</p> Signup and view all the answers

What type of bond can cysteines form?

<p>Disulphide bonds</p> Signup and view all the answers

What is the name of the tetrapeptide: Alanylglutamylglycyllysine?

<p>Alanylglutamylglycyllysine</p> Signup and view all the answers

What is the suffix used for oligopeptides containing 2-10 amino acids?

<p>di, tri, tetra, penta, hexa, hepta, octa, nona, deca</p> Signup and view all the answers

What peptide is involved in pain control?

<p>Leucine enkephalin</p> Signup and view all the answers

What is the pH electrophoresis profile used to indicate?

<p>Protein isoelectric points</p> Signup and view all the answers

What is insulin made from?

<p>Two chains of amino acids</p> Signup and view all the answers

How are cysteines linked in glutathione?

<p>Via disulphide bonds</p> Signup and view all the answers

What do short chains of amino acids form when linked together by peptide bonds?

<p>Oligopeptides</p> Signup and view all the answers

What is the suffix used for polypeptides with between 10-50 residues?

<p>Polypeptides</p> Signup and view all the answers

What stabilizes peptide bonds by delocalization energy?

<p>Resonance</p> Signup and view all the answers

What is the name of the pentapeptide: Ser-Gly-Tyr-Ala-Leu?

<p>Serylglycyltyrosylalanylleucine</p> Signup and view all the answers

Study Notes

Proteins and Amino Acids

  • Proteins are synthesized from nucleic acids, which encode the instructions for their formation.
  • Glycine, the only achiral amino acid among the 20 common types, has no stereoisomer.
  • All naturally occurring amino acids exist primarily in the L-optical form.
  • Amino acids possess an acidic group and lack a basic group.
  • Aromatic amino acids play a significant role in protein visualization due to their unique properties.
  • Oligopeptides consist of 2 to 10 amino acids linked together.
  • Proteins typically contain between 50 and 400 amino acid residues.

Peptide Bonds and Structures

  • Peptide bonds exhibit weak resonance, contributing to their stability.
  • A tetrapeptide is characterized by its four amino acid components, starting from the C-terminal amino acid.
  • Cysteines can form disulfide bonds, which stabilize protein structure.
  • Glutathione, an important tripeptide, is composed of glutamic acid, cysteine, and glycine, linked via the side chain of glutamic acid.
  • Insulin is synthesized as a single chain of amino acids, indicating its polypeptide structure.

Techniques and Properties

  • Polyacrylamide gel electrophoresis (PAGE) is utilized for DNA purification and analysis.
  • Isoelectric points, while significant for certain applications, are deemed less critical for characterizing amino acids, peptides, and proteins.
  • Short chains of amino acids linked by peptide bonds form oligopeptides, while longer chains are termed polypeptides.

Additional Key Points

  • Cysteines in glutathione are linked through disulfide bonds, enhancing the molecule's stability.
  • Various suffixes identify oligopeptides (2-10 residues) and polypeptides (generally 10-50 residues).
  • The term "isoelectric point" signifies the pH at which an amino acid has no net charge, affecting its behavior in solutions.
  • Glycine is distinctly recognized for its lack of chirality among common amino acids.
  • Insulin, critical for glucose regulation, is formed from a specific sequence of amino acids.
  • The profile in pH electrophoresis indicates the protein's charge and structure.
  • The pentapeptide Ser-Gly-Tyr-Ala-Leu is a specific sequence that illustrates peptide bonding.

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Related Documents

PHA111 Amino Acids.pptx

Description

Test your knowledge of amino acids, peptides, and proteins in nature with this quiz based on the MPharm PHA111Amino Acids & Peptides lecture by Dr. Mark Gray. The quiz covers recommended readings and key concepts discussed in the lecture slides.

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