Amino Acids and Proteins Flashcards
Amino acids are chiral which gives them what property?
They are optically active
Amino acids have an NH2 group and a COOH group. What property does this give them?
They can act as a base and an acid
HOOCCH2NH2 + HCl –> _______? Is glycine exhibiting acid or base properties?
HOOCCH2NH2 + HCl –> HOOCCH2NH3+Cl-
Base
HOOCCH2NH2 + NaOH –> ______? Is glycine exhibiting acidic or basic properties?
Na+OOCCH2NH2 + H2O
Acid
What is a zwitterion?
An ion with a positive charge and a negative charge which is overall neutral
How are peptides formed?
Can form via an amide or peptide bond between 2 amino acids
Why would we break down a protein?
To tell us which amino acids are in the polypeptide chain
Why is the melting point of amino acids so high compared to molecules with similar molecular weight?
In neutral conditions, amino acids will become zwitter ions. This is where the amine group gains a hydrogen, making it a positive group and the carboxyl group loses a hydrogen, making it a negative group. This causes ionic bonds to form between amino acids and hence its high melting point.
In neutral conditions, why do the amine and carboxyl groups act as in a zwitterion?
The amine group acts as a base as it gains a H+, while the carboxyl group acts as an acid as it donates a H+
What properties do the R group of an amino acid give?
The R group determines the amino acids size, polarity and its name.
What happens to amino acids in acidic conditions?
In acidic conditions, all amine groups change to NH3+, including in the R group.
What happens to amino acids in alkali conditions?
In alkali conditions, all carboxyl groups change to COO-, including in the R group.
Are amino acids soluble?
Yes, as they form ion-dipole forces with water.
