structure and properties of amino acids




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   
ANS: C - a zwitterions

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2).
What is the end product of leucine metabolism?
A   Acetyl-CoA   
B   Pyruvic acid   
C   Oxaloacetic acid   
D   Acetyl carnitine   
ANS: D - Acetyl carnitine

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3).
What is the heaviest of the twenty amino acids?
A   Phenylalanine   
B   Tryptophan   
C   Tyrosine   
D   Histidine   
ANS: B - Tryptophan

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4).
Which of the following amino acids can form hydrogen bonds with their side (R) groups?
A   Asparagine   
B   Aspartic acid   
C   Glutamine   
D   All of these   
ANS: D - All of these

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5).
The isoelectric point of an amino acid is defined as the pH
A   where the molecule carries no electric charge   
B   where the carboxyl group is uncharged   
C   where the amino group is uncharged   
D   of maximum electrolytic mobility   
ANS: A - where the molecule carries no electric charge

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6).
Molecules that bear charged groups of opposite polarity are known as
A   zwitterions   
B   ambions   
C   ion conversion   
D   amphions   
ANS: A - zwitterions

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7).
What is the product of the catabolic breakdown of Arginine?
A   Alpha-ketoglutarate   
B   Fumarate   
C   Oxaloacetate   
D   Succinate   
ANS: A - Alpha-ketoglutarate

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8).
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   
ANS: A - Isoleucine, valine and phenylalanine

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9).
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   
ANS: C - the body cannot synthesize

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10).
D-Alanine and L-Alanine are technically known as
A   anomers   
B   enantiomers   
C   epimers   
D   polymer   
ANS: B - enantiomers

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