E-PolyLearning

21. Which amino acids would most likely reside in the membrane-anchoring domain of a membrane embedded protein?
a. Isoleucine, valine and phenylalanine
b. Phenylalanine, valine, and aspartate
c. Leucine, threonine, and lysine
d. Lysine, arginine and histidine
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Answer: (a).Isoleucine, valine and phenylalanine

22. An essential amino acid is one that
a. is essentially easy to synthesize
b. is essential to flagella motion
c. the body cannot synthesize
d. the body can synthesize under essential conditions
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Answer: (c).the body cannot synthesize

23. D-Alanine and L-Alanine are technically known as
a. anomers
b. enantiomers
c. epimers
d. polymer
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Answer: (b).enantiomers

24. Which of the following pairs of amino acids would carry a negative charge on their side chain at pH 8.0?
a. Asparagine & Glutamine
b. Leucine & Glycine
c. Histidine & Lysine
d. Aspartate & Glutamate
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Answer: (d).Aspartate & Glutamate

25. In a polypeptide average mass of an amino acid residue is
a. 110 daltons
b. 118 daltons
c. 80 daltons
d. 150 daltons
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Answer: (a).110 daltons

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