Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

18. Amino Acids and Proteins

Peptides

GOB Chemistry

18. Amino Acids and Proteins

Peptides

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0:54 minutes

Problem 18c

Textbook Question

Draw the structural formula for each of the following peptides:
c. Val—Arg

Verified step by step guidance

Identify the amino acids involved in the peptide. In this case, the peptide consists of Valine (Val) and Arginine (Arg).

Recall the general structure of an amino acid: an amino group (

\text{-NH}_2

), a carboxyl group (

\text{-COOH}

), a hydrogen atom, and a unique side chain (R-group) attached to a central carbon atom (alpha carbon).

Determine the side chains for Valine and Arginine. Valine has a branched alkyl side chain (

\text{-CH(CH}_3\text{)_2}

), and Arginine has a guanidino group (

\text{-CH}_2\text{-CH}_2\text{-NH-C(NH)_2}

Form the peptide bond between the carboxyl group of Valine and the amino group of Arginine. A peptide bond is a covalent bond formed by a condensation reaction, where a molecule of water is removed, linking the carbon of the carboxyl group to the nitrogen of the amino group.

Draw the structural formula of the dipeptide Val—Arg, ensuring the peptide bond is correctly represented and the side chains of Valine and Arginine are accurately depicted.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Peptide Structure

Peptides are short chains of amino acids linked by peptide bonds. The structure of a peptide is determined by the sequence of its constituent amino acids, which influences its properties and functions. Understanding the basic structure of peptides is essential for drawing their structural formulas.

Amino Acids

Amino acids are the building blocks of peptides and proteins, each containing an amino group, a carboxyl group, and a unique side chain (R group). The specific properties of the amino acids, such as polarity and charge, affect the overall structure and function of the peptide. In the case of Val—Arg, valine and arginine are the two amino acids involved.

Peptide Bond Formation

A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water in a condensation reaction. This bond is crucial for linking amino acids together to form peptides. Understanding how peptide bonds are formed is key to accurately representing the structural formula of peptides.