6.2.2 - Amino Acids, Amides and Chirality

Question 1

What are the two functional
groups of amino acids?

Answer 1

NH2
and COOH (amine and carboxylic acid)

Question 2

Are α-amino acids chiral?
Why?

Answer 2

Yes, one carbon has 4 different substituents.
Except glycine, where R = H

Question 3

What happens to amino
acids in acidic conditions?

Answer 3

Gains a proton on NH2
group
NH3+

Question 4

What happens to amino
acids in alkaline conditions?

Answer 4

Loses a proton from COOH group
COO-

Question 5

What is the peptide linkage?

Answer 5

-CONH

Question 6

What property must a
carbon atom have for the
molecule to display optical
isomerism about that carbon
atom?

Answer 6

4 different substituents attached to one carbon
atom

Question 7

What are the similarities and
differences between two
optical isomers?

Answer 7

Same atoms and bonds, but they are non-superimposable
mirror images of one another. NOT IDENTICAL in chemical
properties necessarily.
Differ in the way they rotate plane polarised light - rotate
plane of polarisation by the same angle but in different
directions

Question 8

What word is used to
describe optically active
molecules?

Answer 8

chiral