Concept explainers
To identify:
The substance that cannot be found in the blue area of the starch agar plate, but in the clear area.
Introduction:
The starch is a polysaccharide made up of glucose. The glucose is linked by glycosidic bonds, which can be hydrolyzed using the amylase enzyme.
Explanation of Solution
The iodine test is the used to test the presence of starch. The starch turns the aqueous solution of triiodide into an intense blue-black color. This is due to the formation of intermolecular charge transfer complex.
The digestion of the starch by amylase gives a negative iodine test, as the amylase converts the starch to glucose. The clear region on a starch agar plate gives a negative test due to the absence of starch and its digestion into glucose.
The glucose and amylase can be found in the clear area.
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Chapter 13 Solutions
Laboratory Experiments in Microbiology (11th Edition)
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