E-PolyLearning

26. Which pair of amino acids absorbs the most UV light at 280 nm?
a. Threonine & Histidine
b. Trp & Tyrosine
c. Cystein & Asparagine
d. Phenylalnine & Proline
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Answer: (b).Trp & Tyrosine

27. Which of the following is a nonstandard amino acid?
a. Cysteine
b. Isoleucine
c. Hydroxyproline
d. Histidine
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Answer: (c).Hydroxyproline

28. Which of the following is an essential amino acid?
a. Tryptophan
b. Methionine
c. Lysine
d. All of these
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Answer: (d).All of these

29. Protein fluorescence arises primarily from which residue?
a. Arginine
b. Tryptophan
c. Tyrosine
d. Phenylalanine
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Answer: (b).Tryptophan

30. Which of the following amino acid is known as half-cystine residue?
a. Cysteine
b. Isoleucine
c. Valine
d. Histidine
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Answer: (a).Cysteine

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