Biochemistry - Structure and Properties of Amino Acids - Discussion

Discussion :: Structure and Properties of Amino Acids - Section 1 (Q.No.1)

1. 

When the amino acid alanine (R-group is CH3) is added to a solution with a pH of 7.3, alanine becomes

[A]. a cation
[B]. nonpolar
[C]. a zwitterions
[D]. an isotope

Answer: Option C

Explanation:

No answer description available for this question.

Mamta Kushwah said: (Dec 22, 2012)  
Because they have pka value is up to 6.7 .

Geofrey Cosmas said: (May 7, 2013)  
The alanine become zwitterionic character because at 7.3 the carboxylic group already ionized and the amino group is still protonated contribution the neutrality, which we call as its ISOELECTRIC POINT. FROM Tanzania.

Regina Sanco said: (Sep 24, 2013)  
The alanine becomes zwitter because at a PH of app 7.3, the carboxyl group COOH of alanine becomes fully deprotonated (a proton is removed) forming COO- whiles the amino group becomes fully protonated forming an NH3+.

Japan Mahinda said: (Mar 6, 2014)  
At ph 7.3 is nearly physiological and alanine exist as a zwitterion as NH3+- C-COO-, SO THE NH3+ and the COOH- CREATES A DIPOLE(ZWITTERION).

Vishal said: (Aug 17, 2014)  
Because they are having both the positive and negative charges.

Wanyama Emmanuel said: (Dec 8, 2014)  
When the amino acid is placed in a solution at physiologic pH, the carboxyl group loses its hydrogen to the amino group, hence it becomes negatively charged while the amino group gets a positively charged.

Kate Wanjiku said: (Jul 6, 2015)  
Because at neutral PH alanine can either act as a base or as an acid.

Wangu said: (Nov 2, 2015)  
The amino group gains hydrogen ion that is lost from the carboxyl group.

Lama Shatat said: (Jun 11, 2016)  
Because at physiologic pH ( ~ pH = 7.4), the carboxyl group is dissociated, forming the negatively charged carboxylate ion(-COO-) and the amino group is protonated(-NH3+).

Abhimanyu Batra said: (Mar 11, 2017)  
Nice explanation. Thank you all.

Kennedy said: (Jun 15, 2017)  
Excellent explanations thanking you all for your help.

Shawul said: (Aug 15, 2017)  
Thank you for explained briefly.

Sheku Swaray said: (Mar 20, 2019)  
Thanks all for explaining.

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