Term
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1. Which of the following amino acids participates the most in protein buffering of blood?
A. Histidine
B. Proline
C. Alanine
D. Tryptophan
E. Phenylalanine
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Definition
A. Histidine
Histidine has imidazole ring.
Functions as a general acid-base catalyst in many enzymes.
Histidine is the only amino acid with good buffering capacity around pH 7, the pH of intracellular fluids and blood.
However, most proteins only contain small amt of Hisidine and therefore do NOT contribute significantly to buffering in biological systems (hemoglobin is an exception)
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Term
The addition of a hydroxyl to _____ produces tyrosine.
A. Valine
B. Tyrosine
C. Phenylalanine
D. Glycine
E. Proline
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Definition
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Term
Optically inactive amino acid?
A. Valine
B. Tyrosine
C. Phenylalanine
D. Glycine
E. Proline
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Definition
D. Glycine
Glycine has two identical hydrogen atoms instead of 4 different groups attached to central carbon so it is the only amino acid that is optically inactive.
Atom geometry is indistinguishable. |
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Term
Precursor of dopamine, epinephrine, and norepinephrine?
A. Valine
B. Tyrosine
C. Phenylalanine
D. Glycine
E. Proline
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Definition
B. Tyrosine
See page 286 for pathway and structures. Also Lectures 1-2
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Term
Imino acid?
A. Valine
B. Tyrosine
C. Phenylalanine
D. Glycine
E. Proline
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Definition
E. Proline
Proline has a secondary amino group that is part of a five-membered ring structure p.4
The unique structure of Proline can have an important role in protein secondary structure alterations.
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