Question

In your research on gene regulation in E. coli, you produce 2 mutant strains with the same phenotype: they can grow on lactose but not on glucose. To investigate these 2 mutants further, you perform a complementation test using them and discover that the diploid combination strain can grow on glucose or lactose. From this, you can deduce that:_______. A) Both mutants have a mutation in the same gene
B) The 2 mutants have mutations in different genes
C) Glucose and lactose metabolic pathways in E. coli utilize at least one shared gene in common
D) At least 2 different genes are required for glucose metabolism in E. coli
E) B and D.

Answer 1

Answer:

E) B and D.

Explanation:

• A test that is used to  determine if two mutations that are associated with a specific phenotype are allelic or non allelic is known as a complementation test.
• If the mutation is allelic then the combination does not complement, but if complementation occurs it shows that the combination is not allelic.
• In the given case, the mutants cannot grow on glucose, however a combination of two strains were able to grow on glucose, this means they are able to complement each other.
• If they complement each other this means that mutations lie on different genes and since, they are affecting the growth on glucose it also confirms that the atleast 2 different genes are required for glucose metabolism in E.coli.