The nomenclature of amino acids involves both systematic IUPAC naming and common trivial names. Each amino acid is characterized by the presence of an amino group (-NH₂) and a carboxyl group (-COOH), which are attached to a central carbon atom. The IUPAC names typically reflect the structure of the amino acids, often incorporating the suffix "-ine" for basic amino acids and "-ic acid" for acidic ones. For example, glycine is the simplest amino acid, named for its sweet taste, while alanine is derived from the Latin word "alanus." Additionally, amino acids are often abbreviated using three-letter codes (e.g., Gly for glycine, Ala for alanine) for convenience in biochemical contexts. The classification of amino acids can also be based on their side chains, which determine their properties and roles in proteins.
What is the general structure of an amino acid?
An amino acid consists of a central carbon atom (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.
How are amino acids classified based on their side chains?
Amino acids can be classified into several categories based on their side chains: non-polar (hydrophobic), polar (hydrophilic), acidic (negatively charged), and basic (positively charged).
What is the IUPAC naming convention for amino acids?
The IUPAC naming convention for amino acids typically involves naming the compound based on the longest carbon chain containing the carboxyl group, followed by the suffix "-ine" for basic amino acids or "-ic acid" for acidic amino acids.
What is the common name for the amino acid with the formula NH₂CH₂COOH?
The common name for NH₂CH₂COOH is glycine, which is the simplest amino acid.
How are essential and non-essential amino acids defined?
Essential amino acids cannot be synthesized by the human body and must be obtained through diet, while non-essential amino acids can be synthesized by the body.
Which of the following is the three-letter abbreviation for glycine?
a) Ala
b) Pro
c) Val
d) Gly
Answer: d) Gly
What is the IUPAC name for aspartic acid?
a) 2-amino-3-hydroxybutanoic acid
b) 2-amino-4-carboxybutanoic acid
c) 2-amino-3-methylbutanoic acid
d) 2-amino-2-methylpropanoic acid
b) 2-amino-4-carboxybutanoic acid
Answer:
Which of the following amino acids is classified as an essential amino acid?
a) Glycine
b) Alanine
c) Valine
d) Serine
Answer: c) Valine
What is the common name for the amino acid with the formula NH₂CH(CH₃)COOH?
a) Proline
b) Leucine
c) Alanine
d) Valine
Answer: d) Valine
Which of the following amino acids has a side chain that contains a sulfur atom?
a) Methionine
b) Cysteine
c) Both A and B
d) None of the above
Answer: c) Both A and B