17.5.5 - Amino acids Flashcards
Why can all amino acids except glycine rotate plane-polarised light, why is this?
All amino acids other than glycine have a chiral centre.
Why are amino acids solid at room temperature?
They are zwitterions that can form ionic interactions between each other.
What are zwitterions?
When an amino acid is electrically neutral because it has a positive and a negative charge that balance each other.
What is the isoelectric point?
The pH at which the zwitterion exists in aqueous solution.
What does a low isoelectric point indicate?
That the molecule is predominantly acidic.
What happens to the NH2 group of an amino acid in acidic solution?
It gains a proton to become NH3
+
What happens to the COOH group of an amino acid in alkaline solution?
It loses a proton to form a COO- group.
