BIOLOGY
AMINO ACIDS
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
Alanine has two pKa (2.35, 9.87). What is the net charge of alanine at pH = 11?
|
|
0
|
|
|
-1
|
|
|
+1
|
|
|
None of the above
|
Explanation:
Detailed explanation-1: -At a pH greater than 10, the amine exists as a neutral base and the carboxyl as its conjugate base, so the alanine molecule has a net negative charge.
Detailed explanation-2: -At neutral pH (pH 7), alanine exists as a zwitterion which means it has a zero net charge.
Detailed explanation-3: -The pKa1 and pKa2 values of alanine are 2.3 and 9.7 respectively.
Detailed explanation-4: -As a result, the structure of alanine at a given pH is as follows: This implies that at pH 10, the charge of alanine is-1.
There is 1 question to complete.