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17 Cards in this Set
- Front
- Back
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3 substituents of an amino acid
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Amino group
Carboxylic acid group R-group |
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At what pH are amino acids in zwitterionic form?
i.e. What is physiological pH? |
~ pH 7.8
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Define:
Dipeptide Tripeptide Oligopeptide Polypeptide |
Dipeptide - a chain of 2 AA's
Tripeptide - a chain of 3 AA's Oligopeptide - a chain of 3-10 AA's Polypeptide - a chain of > 10 AA's |
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Individual AA's within a polypeptide are called...
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...amino acid residues
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The structure of most polypeptides depends upon the...
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...Hydrophobic Effect.
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Define:
Zwitterionic form |
Total charge on a molecule is zero, but it contains portions +ve and -ve charge (which sum to zero).
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the pK value of the *carboxyl group* attached to the α-carbon is usually around...
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2.2
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the pK value of the *amino group* attached to the α-carbon is usually around...
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9.4
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Define:
Isoelectric Point |
pI
The pH at which there is no net charge. |
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Within globular proteins, non-polar amino acids are located:
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At the center
Transmembrane domain doing non-polar interactions |
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All amino acids are optically active except...
Why? |
Glycine
Because the central carbon does not have 4 different substituent groups |
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Which stereochemical configuration do all amino acids derived from proteins have?
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L-configuration
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Cysteine can form _____ bonds.
Why is this important? |
disulfide
disulfide bonds can link polypeptide chains |
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Polypeptides are joined via a _____ bond and formed via. a _____ reaction
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peptide
condensation |
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Amino acids and modified amino acids act as _____ and _____.
What are some examples? |
hormones and neurotransmitters
EXAs: Glycine Glutamic acid λ-aminobutyric acid Seratonin Dopamine |
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Which amino acid has a side group that binds back to the amine?
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Proline
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Which amino acid has the smallest side chain?
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Glycine
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