Lysozyme is an enzyme that breaks down bacterial cell walls and is found in your tears, mucus, and saliva. A mutation occurs in the gene for lysozyme that results in a lysine (a positively charged amino acid) being substituted for an arginine (also a positively charged amino acid). Do you think that the mutant lysozyme will function similarly to the normal lysozyme?
◦ yes, because both lysine and arginine are positively charged so the tertiary structure and therefore function should be similar
◦ no, because all changes in protein primary sequence result in functional differences
◦ no, because changing lysine to arginine will cause the protein to denature
◦ yes, because protein function stays the same no matter what mutations occur
An example of polymorphism: the two colour variations found in the orchid Dactylorhiza sambucina.
Plant Cell
Cancer cell.
A Human Cell
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Mechanisms for Regulating Bacterial Gene Expression