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

17. Amines

Amine Reactions

GOB Chemistry

17. Amines

Amine Reactions

Previous problemNext problem

Problem 24b

Textbook Question

The structure of the amino acid lysine (in its uncharged form) is shown below.

b. Is lysine likely to be water-soluble? Explain.

Verified step by step guidance

Step 1: Understand the structure of lysine. Lysine is an amino acid with a side chain containing an amino group (-NH2) attached to a long hydrocarbon chain. It also has the general structure of amino acids, which includes an amino group (-NH2), a carboxyl group (-COOH), and a central carbon atom bonded to a hydrogen atom and the side chain.

Step 2: Recall the concept of solubility. A molecule's solubility in water depends on its ability to form hydrogen bonds with water molecules. Polar or charged groups in a molecule increase its water solubility because they can interact with water's polar nature.

Step 3: Analyze the functional groups in lysine. Lysine contains polar functional groups, such as the amino group (-NH2) and the carboxyl group (-COOH), which can form hydrogen bonds with water. Additionally, the side chain of lysine has another amino group (-NH2), which is also polar and capable of hydrogen bonding.

Step 4: Consider the overall polarity of lysine. Despite the presence of a hydrocarbon chain in the side chain, the multiple polar groups dominate, making lysine a polar molecule overall. This polarity enhances its interaction with water.

Step 5: Conclude based on the analysis. Since lysine has several polar groups capable of forming hydrogen bonds with water, it is likely to be water-soluble. The presence of these groups outweighs the nonpolar hydrocarbon chain in the side chain.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

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

Amino Acid Structure

Amino acids are organic compounds composed of an amino group, a carboxyl group, and a unique side chain (R group). The structure of lysine includes a positively charged amino group in its side chain, which influences its interactions with water and other molecules. Understanding the basic structure of amino acids is essential for predicting their solubility and behavior in biological systems.

Polarity and Solubility

Polarity refers to the distribution of electrical charge around atoms, molecules, or chemical groups. Water is a polar solvent, meaning it dissolves other polar substances well. Lysine, with its polar amino and carboxyl groups, is likely to interact favorably with water, making it water-soluble. This concept is crucial for understanding how amino acids behave in aqueous environments.

Hydrophilic vs. Hydrophobic

Hydrophilic molecules are attracted to water and tend to dissolve in it, while hydrophobic molecules repel water and do not dissolve easily. Lysine, due to its polar side chain and functional groups, is classified as hydrophilic. This classification helps explain why lysine is likely to be water-soluble, as hydrophilic substances readily interact with the polar nature of water.