Lab: Tests For Biochemical Molecules

This is my lab for the tests for biochemical molecules.

First we did the test for fats. We rubbed a piece of cupcake, cheese, apple, lettuce, tomato, bread, butter, orange and pancake on a piece of recycled paper. After a couple of minutes, the ones that consisted of fats left an oily residue behind. Here are some before and after pictures.

Next we did the test for starch. We used a spot plate and a couple of drops of Iodine to determine which ones were positive. We were able to figure that out because a dark purple colour indicates starch is present. Here are some pictures from before and after Iodine solution was added.

*Note: the foods circled on the chart in the photo tested positive.

Our last test was for carbohydrates. We used test tubes filled with water and pieces of the various foods inside a hot bath. We added Benedict solution and waited for two minutes. The ones that turned an orange colour indicated single sugars are present. Here are also some photos.

This is a chart I made that shows the positive and negative items for each category.

Items	Fats	Starch	Carbohydrates
Cupcake	Positive	Positive	Positive
Cheese	Positive	Negative	Positive
Apple	Negative	Negative	Positive
Lettuce	Negative	Negative	Not Tested
Tomato	Negative	Positive	Not Tested
Bread	Negative	Positive	Positive
Butter	Positive	Negative	Negative
Orange	Negative	Negative	Positive
Pancake	Negative	Positive	Not Tested