Question

You join a food chemistry lab where the researchers have found two new additives that are quite good at preventing food from spoiling. Before putting these chemicals out on the market, they decide that they should probably make sure there are no harmful effects to humans. They do an Ames test and observe the following results. Needless to say, they decide not to use the additives on food.

Bacterial Strain his mutation # of colony forming units on plates lacking histidine Untreated Treated Treated with | Treated Treated with with Additive A with Additive B Additive A and liver Additive B and liver extract extract 1.6 + 0.5 1.7 +0. 1 3 .0 + 1.0 2.2 + 0. 4 1 239 + 28 9.3 + 3.0 10+ 4. 0 12 + 3.2 11 + 2.8 12 + 2.2 TAF TAT Frameshift T:A changed to A:T A:T changed to C:G TAG 0.7 +0.3 621 +24 654 + 31 1.0 + 0.5 1.2 + 0.6

What kind of mutation (be as specific as you can) is caused by additive A? Explain your reasoning.

Answer 1

AT to GC mutation - Transition

T 1st replication     G   ------------------------>        G
A --------------------> A' (imino) 2nd replication     C

Adenine becomes imino form it will binds to Guanine than Thymine. So, Guanine now makes bonds with Cytosine.