Lecute 6

Question 1

How many naturally occurring amino acids

Answer 1

20

Question 2

How many naturally occurring amino acids have chiral carbons

Answer 2

19

(18 have s stereochemistry)

Question 3

2 functional groups on amino acids

Answer 3

• NH2
• COOH

Question 4

A b and y amino acids

Answer 4

• when -NH2 and -COOH groups on the same C
• a amino acids
• a means that the NH2 is o the carbon next to c=o

Question 5

All the amino acids expect glycine are

Answer 5

• chairal molecuels so exist as a part of enentomers
• they have a stereogenic centre

Question 6

3D arrangement of groups of amino acids

Answer 6

• all have the same 3D arrangement apart from cysteine
• all S configuration apart from cysteine
• Fischer projection is drawn with COOH at top
• L if NH2 is on left - all natural chiral amino acids exist in the L-form

Question 7

Side chains

Answer 7

• the difference between various amino acids

Question 8

Nature of side chains

Answer 8

Question 9

Chemistry of amino acids

Answer 9

• dictated by the functional groups
• NH2 is a nucleophiles and a base
• COOH acid, nucleophillic substitution
• any additional functionality in the side chain
• a carboxylic acid is a weak acid and an amine is a weak base!!!!!!!!!
• the fact these two groups are in close proximity imparts properties on the a-amino acids

Question 10

The PI is…

Answer 10

An important structural parameter as it influences a molecules solubility and its electro mobility in analytic techniques such as electrophoresis

Question 11

Electrophoresis

Answer 11

• separation/ analytical technique that discriminates molecules on their electro mobility and thus overall charge

Question 12

Amino acids in ther charged form dominates rather then non-ionic form