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

Amino Acid Classifications

GOB Chemistry

18. Amino Acids and Proteins

Amino Acid Classifications

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3:08 minutes

Problem 1b

Textbook Question

Draw the structure for each of the following amino acids and put an asterisk (*) next to any chiral carbon centers in your structure:
b. lysine

Verified step by step guidance

Step 1: Understand the structure of lysine. Lysine is an amino acid with the molecular formula C6H14N2O2. It contains an amino group (-NH2), a carboxyl group (-COOH), and a side chain with a long aliphatic chain ending in another amino group (-CH2-CH2-CH2-CH2-NH2).

Step 2: Draw the backbone structure of lysine. Start with the central alpha carbon (Cα) bonded to the amino group (-NH2), the carboxyl group (-COOH), a hydrogen atom, and the side chain (-CH2-CH2-CH2-CH2-NH2).

Step 3: Identify the chiral carbon. A chiral carbon is a carbon atom bonded to four different groups. In lysine, the alpha carbon (Cα) is bonded to the amino group, carboxyl group, hydrogen atom, and the side chain, making it a chiral center. Place an asterisk (*) next to the alpha carbon in your structure.

Step 4: Complete the structure by ensuring all bonds are correctly drawn and the side chain is fully represented. The side chain consists of four methylene groups (-CH2-) followed by a terminal amino group (-NH2).

Step 5: Double-check your structure for accuracy. Ensure the alpha carbon is marked as chiral with an asterisk (*) and confirm that all functional groups are correctly positioned and labeled.

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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 that serve as the building blocks of proteins. Each amino acid consists of a central carbon atom (the alpha carbon) bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group) that determines the specific properties of the amino acid.

Chirality

Chirality refers to the geometric property of a molecule having a non-superimposable mirror image, much like left and right hands. In amino acids, chirality is often associated with the presence of a chiral carbon atom, which is a carbon atom bonded to four different groups. This property is crucial in biochemistry, as the chirality of amino acids can affect protein structure and function.

Lysine Structure

Lysine is an essential amino acid characterized by its side chain containing an additional amino group, making it a positively charged molecule at physiological pH. The structure of lysine includes a chiral center at the alpha carbon, and it is important to identify this chiral center when drawing its structure, as it influences the amino acid's interactions and roles in proteins.

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Textbook Question

What are some differences between each of the following pairs?

c. polar and nonpolar amino acids

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Textbook Question

How does the polarity of the R group in leucine compare to the R group in serine?

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Textbook Question

Draw the structure for each of the following amino acids at physiological pH:

a. lysine

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Textbook Question

Classify each of the amino acids in problem 16.5 as polar or nonpolar. If polar, indicate if the R group is neutral, acidic, or basic. Indicate if each is hydrophobic or hydrophilic.

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Textbook Question

Classify each of the amino acids in Problem 10.1 as polar (neutral, acidic, or basic) or nonpolar and as hydrophobic or hydrophilic.

a. alanine

b. lysine

c. tryptophan

d. aspartate

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Textbook Question

Give the three-letter and one-letter abbreviations and identify the functional group in the side chain for each amino acid in Problem 10.1.