In this set of activities, students develop research questions and design experiments to investigate the role of microorganisms in the decomposition of a carrot. The students not only observe the carrot in various states of decomposition but also isolate the bacteria and fungi responsible for this process. After selecting one of the types of bacteria they have isolated, students use biochemical tests to identify the enzymes that enable these microbes to digest various types of compounds. Finally, they relate the digesive capabilities of their test organisms to the composition of a carrot and the environment in which the microbes live.

Downloadable files:

Teacher's Guide
Sample Data Collection Sheet

Student Materials:

• Handout #1: Designing an experiment to investigate the microbiology of decay
• Handout #2: Collecting data related to the process of decay
• Handout #3: Culturing decomposer microbes
• Handout #4: Describing culture plates and isolating selected types of bacteria
• Handout #5: Investigating biochemical capabilites of the selected microbes
• Handout #6: Inoculating culture media
• Handout #7: Using results of biochemical tests to draw conclusions about digestive abilities of selected types of bacteria