Two strains of E.coli-one of which can turn on its lactase production and one that cannot-are grown together with lactose in the medium.If all other conditions are equal,what will occur?
A) Both strains will continue to be present in equal amounts.
B) The two strains will kill each other off.
C) The strain that can turn on lactase production will overgrow the culture and be the only one left.
D) The strain that cannot turn on lactase production will overgrow the culture and be the only one left.
E) The strain that can turn on lactase production will make its own lactose once the lactose present in the medium is completely used.

Question

Quizplus · Accepted Answer

The strain that can turn on lactase production will have a selective advantage over the strain that cannot, as it will be able to utilize the lactose in the medium more efficiently. This will lead to the lactase-producing strain outcompeting the non-lactase-producing strain and eventually becoming the only one left in the culture.

Two Strains of E