17 Questions
What are the two functional groups present in all amino acids?
amine and carboxylic acid
What is the pH range at which the amino acid is overall neutral?
pH 7-9
What is the relationship between the pKa of the carboxylic acid group and the pKa of the protonated amine group?
The pKa of the carboxylic acid group is lower than the pKa of the protonated amine group
What is the purpose of breaking down a polypeptide into its component amino acids?
To assign pKa values to each amino acid
What is the R group in an amino acid?
A side chain that varies between different amino acids
What are the two functional groups present in an amino acid, other than the R group?
carboxylic acid (-COOH) and amine (-NH2)
How do D-sugars and L-sugars differ in their rotation of plane-polarized light?
D-sugars rotate light clockwise (dextrorotatory), while L-sugars rotate light counterclockwise (levorotatory)
What type of bonds connect amino acids in a peptide chain?
amide bonds
How do you determine the D/L configuration of an amino acid?
based on its optical rotation, using the D/L system
What is the difference between the N-terminus and C-terminus of a peptide chain?
The N-terminus is the amino end, where the amine group is free, while the C-terminus is the carboxyl end, where the carboxyl group is free
Why can't a peptide chain be formed by simply throwing amino acids together?
because the amino acids must be joined through peptide bonds, which require specific chemical reactions and conditions
What is the purpose of protecting groups in peptide synthesis?
To protect the C-terminus and N-terminus of amino acids from reacting with other molecules during the synthesis process.
What is the abbreviation for the protecting group commonly used for amines?
Boc
What is the reagent used to couple amino acids together in peptide synthesis?
DCC (dicyclohexylcarbodiimide)
What is the advantage of solid-phase synthesis, also known as Merrifield synthesis?
It allows for easier purification and automation of the synthesis process.
What is the purpose of using a base like NaHCO3 in peptide synthesis?
To facilitate the deprotection of protecting groups and promote the formation of peptide bonds.
What is the role of Pd/C in peptide synthesis?
It is used to remove protecting groups, such as Boc.
Test your understanding of amino acids, including their structure, properties, and ionization behavior. Learn about the different types of amino acids and their characteristics. Quiz yourself on the pKa values and protonation states of amino acids.
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