Question

In the Ames test for mutagenicity, why was rat liver extract included in the control sample?

Multiple Choice
Rat liver extract contains enzymes that may be necessary for certain mutagens to work. Since it must be added to the experimental sample, it is also added to the control sample.
Rat liver extract was being tested for its mutagenic properties
Rat liver extract serves as an indicator for mutagenicity. It allows scientists to count the mutated colonies in each sample.
Rat liver extract contains enzymes that may be necessary for certain mutagens to work. Mutagenicity of rat liver extract alone was tested by the control, while mutagenicity of a chemical mutagen alone was tested in the second sample
Bacterial cells can only make the amino acid histidine if rat liver extract is present

Answer 1

The correct answer is: Rat liver extract contains enzymes that may be necessary for certain mutagens to work.

Therefore, in the Ames test for mutagenicity, it is included in the control sample to ensure that any observed mutations are caused by the mutagen being tested and not by the absence of necessary enzymes. The mutagenicity of rat liver extract alone is tested by the control, while the mutagenicity of a chemical mutagen alone is tested in the second sample.
Rat liver extract contains enzymes that may be necessary for certain mutagens to work. Since it must be added to the experimental sample, it is also added to the control sample.

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