Textbook Question
What kind of biological function would each of the following proteins perform?
c. Protease
Ch.18 Amino Acids and Proteins
McMurry8th EditionFundamentals of GOBISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
Chapter 18, Problem 45a
Name and draw the structures of the amino acids that fit the following descriptions:
a. Contains an isopropyl group
Verified step by step guidance1
Step 1: Recall that amino acids are organic compounds containing both an amino group (-NH₂) and a carboxyl group (-COOH), along with a unique side chain (R group) that determines their identity.
Step 2: Identify the amino acid that contains an isopropyl group in its side chain. An isopropyl group is a branched alkyl group with the structure -CH(CH₃)₂.
Step 3: The amino acid with an isopropyl group in its side chain is **valine**. Its side chain is -CH(CH₃)₂, making it a nonpolar, hydrophobic amino acid.
Step 4: Draw the structure of valine. The general structure of an amino acid is: H₂N-CH(R)-COOH, where R is the side chain. For valine, R = -CH(CH₃)₂. The full structure is: H₂N-CH(-CH(CH₃)₂)-COOH.
Step 5: Label the functional groups in the structure. Highlight the amino group (-NH₂), the carboxyl group (-COOH), and the isopropyl side chain (-CH(CH₃)₂) to ensure clarity in the representation of valine.
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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 has 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. Understanding the general structure of amino acids is essential for identifying specific ones based on their side chains.
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Amino Acid Catabolism: Amino Group Example 2
Isopropyl Group
The isopropyl group is a branched alkyl group derived from propane, consisting of three carbon atoms with the structure -CH(CH3)2. In the context of amino acids, the presence of an isopropyl group in the side chain indicates that the amino acid has a hydrophobic character, influencing its interactions and positioning within proteins. Recognizing this group is crucial for identifying the correct amino acid.
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Hydrophobic Interactions
Hydrophobic interactions refer to the tendency of nonpolar substances to aggregate in aqueous solutions to minimize their exposure to water. Amino acids with hydrophobic side chains, such as those containing isopropyl groups, play a significant role in protein folding and stability. Understanding these interactions helps in predicting how amino acids will behave in a protein's three-dimensional structure.
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Related Practice
Textbook Question
What amino acids do the following abbreviations stand for? Draw the structure of each.
a. Val
Textbook Question
Name and draw the structures of the amino acids that fit the following descriptions:
a. Contains a thiol group
Textbook Question
Draw leucine and identify any chiral carbon atoms with arrows.
1
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Textbook Question
Is phenylalanine hydrophilic or hydrophobic? Explain why.
Textbook Question
At neutral pH, which of the following amino acids has a net positive charge, which has a net negative charge, and which is neutral? (Hint: Draw the various charged forms of each amino acid before deciding.)
a. Asparagine
b. Lysine
c. Proline