Amino acids (a-amino acids)

Question 1

What are alpha amino acids?

Answer 1

Contain an amine (NH2) group and a carboxylic acid (COOH) group bonded to the SAME C atom

Question 2

What is the general formula of alpha amino acids?

Answer 2

General formula: RCH(NH2)COOH

Question 3

What is the simplest amino acid?

Answer 3

Glycine, R group is H

Question 4

What amino acids can show optical isomerism and why?

Answer 4

All a-amino acids except glycine as they have a chiral C

Question 5

What is a chiral carbon?

Answer 5

A carbon bonded to 4 different groups of atoms

Question 6

How do amino acids react with acids?

Answer 6

The NH2 group (amino group/s) reacts to form an ammonium ion (NH3+)
The lone pair of e- on N form dative covalent bond with proton from acid
E.G.
(CH3)2CH(NH2)COOH + H+ —> (CH3)2CH(NH3+)COOH
H2N(CH2)4CH(NH2)COOOH + H+ —> H3N+(CH2)4CH(NH3+)COOH

Question 7

How do amino acids react with bases?

Answer 7

-COOH group/s react to form carboxylate ion
HOOCCH2CH(NH2)COOH + 2H+ —> -OOCCH2CH(NH2)COO- + 2H20

Question 8

How do amino acids react with alcohols?

Answer 8

In the presence of con. sulfuric acid and heat to make ester + water
E.g
alanine + ethanol + H+
The H+ from the acid joins to NH2, making an ammonium ion (NH3+)