Question

Draw zwitterion forms of these amino acids. (a) Valine (b) Phenylalanine (c) Glutamine

Short answer

Answer: The zwitterion forms of the given amino acids are as follows: - Valine (zwitterion form): H3N+ - CH(CH3)2 - COO- - Phenylalanine (zwitterion form): H3N+ - CH2 - C6H5 - COO- - Glutamine (zwitterion form): H3N+ - CH2 - CH2 - CONH2 - COO-

Step-by-step solution

Draw the structures of Valine, Phenylalanine, and Glutamine

First, we need to identify the structure of each amino acid. Here are the structures: (a) Valine: H3N+ - CH(CH3)2 - COO- (b) Phenylalanine: H3N+ - CH2 - C6H5 - COO- (c) Glutamine: H3N+ - CH2 - CH2 - CONH2 - COO-

Draw the zwitterionic forms of each amino acid

(a) Valine: For Valine, we can see that the amino group has already gained a proton and the carboxyl group has already lost a proton, so the given structure is a zwitterion: Valine (zwitterion form): H3N+ - CH(CH3)2 - COO- (b) Phenylalanine: For Phenylalanine, we need to convert the amino group and carboxyl group to their charged forms. First, we will add a proton to the amino group, turning it into a positively charged -NH3+ group. Then, we will remove a proton from the carboxyl group, turning it into a negatively charged -COO- group. Phenylalanine (zwitterion form): H3N+ - CH2 - C6H5 - COO- (c) Glutamine: For Glutamine, the amino group has already gained a proton and the carboxyl group has already lost a proton, so the given structure is a zwitterion: Glutamine (zwitterion form): H3N+ - CH2 - CH2 - CONH2 - COO-