An isolated chain of islands known as the squirrel islands exists in the Pacific Ocean.The island group consists of three separate islands named A, B, and C.The three islands are each 5 miles apart.See diagram below.

The islands support various wildlife including a population of 10,000 squirrels per island.Although the island group is isolated, there is a bit of mixing of squirrels between islands.Occasionally a very ambitious squirrel will swim from one island to another in search of a better life.It is rare—but it does happen.

One day, on island B, a squirrel was born that was named Chip by his parents. Chip looked like all the other squirrels on the island on the surface but was actually a mutant.

CHIPS – the mutantsNORMALS- the non mutants

When Chip was just a one-celled embryo, one base a “T” in his DNA was changed to a “C”.The change happened in a gene that coded for an electron transport chain enzyme.This mutation is carried in all cells of his body.The mutation has both positive and negative effects on chip.

— On the down side, Chip still makes the ETC enzyme but it has a slightly different shape and doesn’t work as well.This means that his ETC won’t generate a hydrogen ion gradient as quickly as the normal squirrels.He has to consume more glucose than other squirrels in order to make the same amount of ATP.The result is that Chip and all of his descendants when he has them will have to eat 5 nuts a day in order to survive, while the normal squirrels have to only consume 4 nuts a day to survive.

+ On the positive side, Chip is now resistant to Cyanide. The chemical cyanide kills squirrels by binding to an enzyme in the squirrels ETC.When the cyanide binds to the enzyme, the ETC halts and the squirrel will quickly die.The mutation that chip carries alters the shape of the enzyme that cyanide is supposed to bind to and cyanide will no longer bind to the enzyme making him completely resistant to cyanide.Yay!

A) The analogy of Squirrel Island has a lot in common with the problem we have today with antibiotic resistance.Think about antibiotic resistance, what do the pieces of the analogy represent in antibiotic resistance?


Normal Squirrels:

Chip the mutant Squirrels:


B) Which of the 5 resistance mechanisms did Chip exhibit when he became resistant to cyanide?

C) Name 3 things that we could do to decrease antibiotic resistance in bacterial populations.

D) The following are all false statements about antibiotic resistance.Write a few sentences that describes why the ideas are incorrect and propose a more correct sentence.

1) Antibiotics are changing and consequently have become weak

2) People have become immune to antibiotics

E) Why do you think it is very important to complete the full course of an antibiotic, prescribed by doctor, to reduce the chance of development of antibiotic resistance?

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