Question

The Ames test demonstrates that?

1) Spontaneous mutations are random.
2) Certain chemicals are mutagenic.
3) Transcription factors bind to DNA at specific sequences.
4) DNA wraps around histones in eukaryotic chromosomes.
5) One gene-one enzyme hypothesis

Answer 1

The Ames test is a biological assay that helps identify mutagenic chemicals by assessing their potential to cause mutations in the DNA of bacteria.

Step-by-step explanation:

The Ames test demonstrates that certain chemicals are mutagenic. It is a biological assay used to assess the mutagenic potential of chemical compounds. By using a strain of Salmonella that is unable to produce histidine due to a genetic mutation, the Ames test measures whether a chemical causes mutations that restore the bacteria's ability to synthesize histidine. Compounds that lead to a higher number of such reversion mutants are considered more mutagenic and, therefore, have a higher potential to be carcinogenic. The test is preferable to animal models as it is quicker and less expensive, though it may produce false positives or negatives.

Additionally, because many chemicals are not directly mutagenic but become so after metabolism, the Ames test often includes rat liver extract to simulate liver metabolism. After the Ames test identifies a compound as mutagenic, further testing with models such as rodents is conducted to determine the substance's carcinogenic properties.