Module 4, lectures 5,6

Question 1

What are the carboxylic acid derivatives?

Answer 1

Carboxylic acid
ester
primary amide
secondary amide
tertiary amide
acid anhydride
acid chloride

Question 2

Describe the reactivity of the carboxylic acid derivatives?

Answer 2

nucleophile reacts by forming bond to the carbonyl carbon in the rate determining step – reactivity of acid derivative is determined by the size. of the partial positive charge on the carbonyl carbon, which results from the electron withdrawing ability of the carbonyl O PLUS the L group

Question 3

What Is one way to predict the reactivity of a derivative?

Answer 3

small = unreactive
Large = reactive

Question 4

What derivative is the least reactive?

Answer 4

Amines due to resonance structures.

Question 5

What is the structure of amino acids?

Answer 5

Amino Acids contain two functional groups – an amine and a carboxylic acid – and one of 20 sidechains (R).
All amino acids are chiral (the central C, called the a carbon, is an asymmetric centre), and so have enantiomers – EXCEPT glycine which has R = H.

Question 6

Describe the fissure projection of amino acids?

Answer 6

Fisher projections of amino acids have the COOH group at the top and the R group. at the bottom. The position of the NH2 group then determines if the amino acid is D
or L. (NH2 on left = L)

Question 7

How is organic chemistry associated with acid-base chemistry?

Answer 7

Each functional group has a pKa value, associated with its ability to donate a H+ to
water.

Question 8

What is PI?

Answer 8

The pI is the average of the two pKa values.
If the amino acid has an R group which itself has a functional group with a pKa value, then the pI is the average of the two most similar pKa values.

Question 9

What is Electrophoresis

Answer 9

A method for separating amino acids based on their charge