Day 7: The Case of the Missing iPod

Today's class was when I got to do something I'd always wanted to do: act like I was Sherlock Holmes.  We were given two lab options. Both were about macromolecules. One was the boring straightforward way, and the other was the mysterious and exciting way.

I think we both know which one I picked.

Michelle and I took on the roles of Sherlock Holmes and Dr. John H. Watson (the H stands for Hamish) and attempted to solve the case of Jerell's missing iPod.

Long story short, Jerell left his iPod with his stuff during lunch at work when his girlfriend came to visit him for lunch. When he came back, it mysteriously disappeared, In its place were a few crumbs of food.

Suspects: The four other workers taking a lunch break at that time: Jose, who was eating a bean and cheese burrito, Ashley, who had some fat-free yogurt, Bruce was eating toast with butter and jelly, and Kiara munched on some pretzels. Each one had a different lunch and only one would match the results of the crumbs left at the scene of the crime.

First, Michelle and I tested the macromolecule composition of vegetable oil, glucose, starch, egg whites, and water for signs of glucose, starch, protein, and lipids. We'd found that vegetable oil contains lipids, glucose contains glucose (well duh), starch contains starch (again, I had no idea) and egg whites contain protein.

Using that, we could infer which foods had which macromolecule.

Our dry and liquid evidence found contained only glucose.

We used bits of the food from the suspects to determine who stole the iPod. And with that, we ran them through a series of tests.

Carbohydrates
In order to find glucose, we had to heat up the substance with some benedict solution. If the solution turned from blue to orange, there was glucose in there.

Glucose was present in the pretzels, jelly, and yogurt, but not in the butter or beans. So that means Jose is out of the running. Bruce is still in there because he also had jelly which came out positive for glucose.

Next was the iodine test for starch. I don't have a picture for it, but if the iodine goes from an orangish color to a dark blue/black color, then it's positive.

Starch was present in the pretzels, yogurt, and beans but not in the butter or jelly.

There was no starch found in the evidence so Kiara, Ashley, and Jose are not the their.

All signs are pointing to Bruce but we still needed to make sure.

We continued with a biuret test for protein. If the Biuret goes from blue to lavender, then it's positive.

Only the fat free yogurt came out as positive and that was already out of the running, so it's really looking like Bruce stole the iPod right now. 

But we had one more test to make sure: the lipids test. For this one, we dipped some cardboard paper into the substance and then waited a bit for the paper to dry. If light passed through the paper, then there were lipids present. Only pretzels had lipids.

So Bruce stole the iPod!!

And that concludes the mystery of the case of the missing iPod.

To see Sherlock Holmes and Dr. John Watson in action, you should visit the Beware the Biology website where I'll have the full story uploaded as my first ever lab report. 

Until next time.