BIOLOGY
AMINO ACIDS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Lysine
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Tryptophan
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Cysteine
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Methionine
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Detailed explanation-1: -There are three amino acids that have basic side chains at neutral pH. These are arginine (Arg), lysine (Lys), and histidine (His). Their side chains contain nitrogen and resemble ammonia, which is a base. Hence option (a) is correct.
Detailed explanation-2: -Lysine and arginine are the basic amino acid as they contain more amino group than acidic group.
Detailed explanation-3: -Arginine is the most basic among them because it contains guanidine side group, −(CH2)4NHC(=NH)NH2, which is basic. Lysine has two amine groups, which makes it overall basic because of the second isolated amine group (−(CH2)4NH2). Histidine, on the other hand, contains imidazole group, which is also basic.
Detailed explanation-4: -The basic amino acids lysine (Lys) and arginine (Arg) play important roles in membrane protein activity, the sensing of membrane voltages, and the actions of antimicrobial, toxin, and cell-penetrating peptides.