Amino Acid Structure Quiz

Amino Acid Characteristics

• Alanine: Nonpolar, aliphatic amino acid.
• Valine: Nonpolar, branched-chain amino acid, hydrophobic.
• Isoleucine: Nonpolar, branched-chain amino acid with hydrophobic properties.
• Leucine: Nonpolar, branched-chain amino acid crucial for protein synthesis.
• Methionine: Contains a sulfur atom, nonpolar, initiates protein synthesis.
• Tyrosine: Polar, can engage in hydrogen bonding; derived from phenylalanine.
• Tryptophan: Nonpolar, precursors to serotonin, has aromatic structure.
• Phenylalanine: Aromatic, nonpolar; needed for synthesizing tyrosine.
• Aspartate: Acidic, negatively charged side chain; involved in metabolic pathways.
• Glutamate: Acidic, important neurotransmitter in the brain, negatively charged.
• Acidic Amino Acids: Aspartate and Glutamate, known for their negatively charged R groups.
• Lysine: Basic, positively charged side chain; involved in protein interaction.
• Arginine: Basic, can donate protons; involved in metabolic functions.
• Histidine: Basic, can switch between charged and uncharged states, vital for enzyme activity.

Polar Amino Acids

• Serine: Polar, contains hydroxyl group; contributes to hydrogen bonds.
• Threonine: Similar to serine, has a hydroxyl group; polar and hydrophilic.
• Asparagine: Polar, possesses a carboxyamide group; involved in hydrogen bonding.
• Glutamine: Similar to asparagine, polar with carboxyamide group; important for nitrogen transport.
• Cysteine: Contains a thiol group, can form disulfide bonds, stabilizing protein structure.

Other Amino Acid Features

• Glycine: Simplest amino acid, fits into tight spaces within proteins due to its small size.
• Proline: Unique imino acid, introduces rigidity in protein structure; often found in turns.
• Hydrophobic Amino Acids: Tend to be buried inside proteins to avoid contact with water (e.g., Glycine, Alanine, Methionine).
• Polar Amino Acids: Include Serine, Threonine, Asparagine, Glutamine, and Cysteine; facilitate hydrogen bonding.

Charge Characteristics

• Acidic Amino Acids: Exhibit negatively charged side chains.
• Basic Amino Acids: Feature positively charged side chains, crucial for interactions with negatively charged groups.

Unique Properties

• Histidine: Unique ability to switch charge based on local pH; involved in enzyme catalysis and protein function.
• Tyrosine: Exceptionally hydrophobic amino acid that can still interact with water due to its hydroxyl group.

Common Groupings

• Nonpolar Hydrophobic Amino Acids: Include Glycine, Alanine, Leucine, Isoleucine, Valine, Proline, Tryptophan, Phenylalanine, Methionine.
• Polar Hydrophilic Amino Acids: Include Serine, Threonine, Tyrosine, Asparagine, Glutamine, Cysteine.

General Knowledge

• Hydrophilic Amino Acids: Basic and acidic amino acids are considered hydrophilic due to their charge properties.