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M.A.R.
M.A.R.
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NotWoodward has answered it perfectly! The glycine which has both positive and negative (resulting neutral charge) is a zwitter ion form. This form is achieved at different pH for different amino acids depending on their R groups.

How does pH actually affect the amino acid? I always break it down when I explain it to my students as follows: An

An amino acid in a very protonated solution (low pH) is going to be saturated with Hydrogenhydrogen ions, so all molecules that can take a proton will take it as they are abundant. Therefore, N will take them and be NH3+become $\ce{NH3+}$ and Carboxythe carboxyl group will take it and form COOH, but as you keep on adding a base (increasing the pH), the base would react with an available proton for neutralisation. 

Therefore, N will easily give away its extra proton and as pH increases will become NH2$\ce{NH2}$. If you continue adding a base, once all N has given away its extra proton, Carboxy group would then give away the proton, resulting in COO-$\ce{COO-}$. So this results in different forms of the same molecule at different pH to attain equilibrium. 

Certain amino acids also have different names based on their states, example: Glutamic acid (R = ---COOHRCOOH) and Glutamate (R = ---COO-$\ce{RCOO-}$).

NotWoodward has answered it perfectly! The glycine which has both positive and negative (resulting neutral charge) is a zwitter ion form. This form is achieved at different pH for different amino acids depending on their R groups.

How does pH actually affect the amino acid? I always break it down when I explain it to my students as follows: An amino acid in a very protonated solution (low pH) is going to be saturated with Hydrogen ions, so all molecules that can take a proton will take it as they are abundant. Therefore, N will take them and be NH3+ and Carboxy group will take it and form COOH, but as you keep on adding a base (increasing the pH), the base would react with an available proton for neutralisation. Therefore, N will easily give away its extra proton and as pH increases will become NH2. If you continue adding a base, once all N has given away its extra proton, Carboxy group would then give away the proton, resulting in COO-. So this results in different forms of the same molecule at different pH to attain equilibrium. Certain amino acids also have different names based on their states, example: Glutamic acid (R = ---COOH) and Glutamate (R = ---COO-)

NotWoodward has answered it perfectly! The glycine which has both positive and negative (resulting neutral charge) is a zwitter ion form. This form is achieved at different pH for different amino acids depending on their R groups.

How does pH actually affect the amino acid? I always break it down when I explain it to my students as follows:

An amino acid in a very protonated solution (low pH) is going to be saturated with hydrogen ions, so all molecules that can take a proton will take it as they are abundant. Therefore, N will take them and become $\ce{NH3+}$ and the carboxyl group will take it and form COOH, but as you keep on adding a base (increasing the pH), the base would react with an available proton for neutralisation. 

Therefore, N will easily give away its extra proton and as pH increases will become $\ce{NH2}$. If you continue adding a base, once all N has given away its extra proton, Carboxy group would then give away the proton, resulting in $\ce{COO-}$. So this results in different forms of the same molecule at different pH to attain equilibrium. 

Certain amino acids also have different names based on their states, example: Glutamic acid (RCOOH) and Glutamate ($\ce{RCOO-}$).

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Sameeta Kambli
Sameeta Kambli
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NotWoodward has answered it perfectly! The glycine which has both positive and negative (resulting neutral charge) is a zwitter ion form. This form is achieved at different pH for different amino acids depending on their R groups.

How does pH actually affect the amino acid? I always break it down when I explain it to my students as follows: An amino acid in a very protonated solution (low pH) is going to be saturated with Hydrogen ions, so all molecules that can take a proton will take it as they are abundant. Therefore, N will take them and be NH3+ and Carboxy group will take it and form COOH, but as you keep on adding a base (increasing the pH), the base would react with an available proton for neutralisation. Therefore, N will easily give away its extra proton and as pH increases will become NH2. If you continue adding a base, once all N has given away its extra proton, Carboxy group would then give away the proton, resulting in COO-. So this results in different forms of the same molecule at different pH to attain equilibrium. Certain amino acids also have different names based on their states, example: Glutamic acid (R = ---COOH) and Glutamate (R = ---COO-)