Photo AI
a. The following structure shows part of a polypeptide: OH I COOH I CH2+ I H I N I CH- C- I CH2- C- I C I COOH I CH2 I N I At a particular pH, an amino acid in solution can exist as ions that have both a negative and positive charge - VCE - SSCE Chemistry - Question 6 - 2009 - Paper 1
Question 6
a. The following structure shows part of a polypeptide: OH I COOH I CH2+ I H I N I CH- C- I CH2- C- I C I COOH I CH2 I N I At a particular pH, an ami... show full transcript
Worked Solution & Example Answer:a. The following structure shows part of a polypeptide: OH I COOH I CH2+ I H I N I CH- C- I CH2- C- I C I COOH I CH2 I N I At a particular pH, an amino acid in solution can exist as ions that have both a negative and positive charge - VCE - SSCE Chemistry - Question 6 - 2009 - Paper 1
Step 1
Step 2
ii. Choose one of the amino acids in this section of polypeptide and draw the structure of its zwitterion clearly showing all bonds.
Answer
I will choose glycine for this part. The zwitterionic form of glycine can be represented as follows:
+
H
|
H2N-C-COO−
|
H
In this structure, the amine group (NH2) is protonated to NH3+, and the carboxylic acid group (COOH) donates a proton, becoming COO−, resulting in a net charge of zero.
Step 3
Give the names of two carbon compounds that can be used to synthesise this ester.
Answer
The two carbon compounds that can be used to synthesize this ester are methanol and an appropriate carboxylic acid, such as acetic acid. The reaction between these two components will produce the ester used in raspberry flavouring.