1. Starter
A dye can be made from 4-methylphenylamine and 2,6-dimethylphenol, shown below
1)Identify the inorganic nitrogen-containing compound formed by the mixture of hydrochloric acid and sodium nitrite.
2) Draw the structure of the organic compound formed in the ice-cold acidic mixture, showing a displayed formula of the nitrogen-containing group.
3)Suggest the structure of the dye.

2. Amino acid
L.O.:
State the general formula for an α-amino acid as RCH(NH2)COOH.
State that an amino acid exists as a zwitterion at a pH value called the isoelectric point.
State that different R– groups in α-amino acids may result in different isoelectric points.
Describe the acid–base properties of α-amino acids at different pH values.

3. General formula of an α-amino acid

4. Structures of some amino acids4

5. The R group
There are 20 different amino acids The only difference is the atoms making up the R group The simplest R group is found in glycine where R = H The largest R group is in tryptophan

6. Where is the alpha carbon in this amino acid?

7. AMINO ACIDS
amine group
carboxylic acid group

8. glycine

9. alanine

10. valine

11. serine

12. aspartic acid

18. amino acids are chiral (except glycine where R = H)
only one enantiomer occurs usually

19. Formation of a zwitterion from glycine
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This document may have been altered from the original 19

20. A zwitterion is a dipolar ionic form of an amino acid that is formed by the donation of a hydrogen ion from the carboxyl group to the amino group.

21. The isoelectric point is the pH value at which the amino acid exists as a zwitter ion.

22. Acid–base reactions of an amino acid22

23. Draw the structure of the amino acid at the pH shown.

24. Draw the structure of the amino acid at the pH shown.

25. Isoelectric Points A Question: pH 3.22? pH 1? pH 13?
If glutamic acid, HOOCCH2CH2CH(NH2)COOH has its isoelectric point at pH 3.22, what will its structure be at:
pH 3.22?
pH 1?
pH 13?