Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

29. Amino Acids

Proteins and Amino Acids

Organic Chemistry

29. Amino Acids

Proteins and Amino Acids

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6:06 minutes

Problem 26

Textbook Question

Draw the tetrapeptide Ala-Thr-Asp-Asn and indicate the peptide bonds.

Verified step by step guidance

Step 1: Understand the structure of each amino acid. Alanine (Ala) has a methyl group (-CH₃) as its side chain, Threonine (Thr) has a hydroxyl group (-CH(OH)CH₃), Aspartic acid (Asp) has a carboxylic acid group (-CH₂COOH), and Asparagine (Asn) has an amide group (-CH₂CONH₂).

Step 2: Identify the general structure of an amino acid. Each amino acid has an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a unique side chain (R group) attached to the central carbon (α-carbon).

Step 3: Link the amino acids in the specified order (Ala-Thr-Asp-Asn) by forming peptide bonds. A peptide bond is formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH₂) of the next amino acid, releasing a molecule of water (H₂O) in a condensation reaction.

Step 4: Draw the tetrapeptide structure. Start with Alanine, connect its carboxyl group to the amino group of Threonine via a peptide bond, then connect Threonine's carboxyl group to the amino group of Aspartic acid, and finally connect Aspartic acid's carboxyl group to the amino group of Asparagine. Ensure the side chains of each amino acid are correctly represented.

Step 5: Indicate the peptide bonds in the structure. Highlight the C=O and N-H bonds that form the peptide linkages between each pair of amino acids. These bonds are the defining feature of the peptide backbone.

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Key Concepts

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

Peptide Bonds

Peptide bonds are covalent bonds that link amino acids together in a protein or peptide chain. They form through a dehydration synthesis reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. This bond is crucial for the structure of proteins, as it determines the sequence and arrangement of amino acids.

Amino Acids

Amino acids are the building blocks of proteins, each consisting of a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group). The side chain determines the properties of each amino acid, influencing the overall structure and function of the resulting peptide or protein. In the context of the question, the specific amino acids Ala (Alanine), Thr (Threonine), Asp (Aspartic acid), and Asn (Asparagine) are to be represented.

Tetrapeptide Structure

A tetrapeptide is a peptide composed of four amino acids linked by peptide bonds. The sequence of amino acids in a tetrapeptide is significant, as it dictates the peptide's properties and biological function. In this case, the tetrapeptide Ala-Thr-Asp-Asn must be drawn to show the correct order and connections, highlighting the peptide bonds between each pair of amino acids.

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Textbook Question

a. Calculate the overall yield of bradykinin when the yield for the addition of each amino acid to the chain is 70%.

b. What would be the overall yield of a peptide containing 15 amino acids if the yield for the incorporation of each is 80%

Textbook Question

What dipeptides would be formed by heating a mixture of valine and N-protected leucine?

Textbook Question

Proof that an imine was formed between aldolase and its substrate was obtained by using D-fructose-1,6-bisphosphate labeled at the C-2 position with ¹⁴C as the substrate. NaBH₄ was added to the reaction mixture. A radioactive product was isolated from the reaction mixture and hydrolyzed in an acidic solution. Draw the structure of the radioactive product obtained from the acidic solution. (Hint: NaBH₄ reduces an imine linkage.)

Textbook Question

Draw the product obtained when a lysine side chain in a polypeptide reacts with maleic anhydride.

Multiple Choice

The unique properties of the 20 common amino acids are determined by which of the following?

Multiple Choice

How many different amino acids are commonly found in proteins?

Multiple Choice

How many standard amino acids are commonly found in proteins?

Multiple Choice

An RNA sequence includes 15 codons. How many amino acids does this sequence encode?

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