Identifying Unknown Bacteria Using
Biochemical and Molecular Methods
Beginning of Instructor Pages
Instructor Pages - - 3
The purpose of this lab is to introduce a variety of lab techniques to students working on the common problem of identifying an unknown bacterium. This lab helps students develop an understanding of the biochemical and molecular differences in bacteria and introduces the concept of identifying species based on characeristic gene sequences. Students work through two types of identification procedures, one classical and one involving DNA sequencing, then compare the results of the two methods.
The lab was created to accompany lecture topics in bacterial genetics and biochemistry. The main topics covered in lecture that relate to this lab are prokaryotic replication, transcription, and translation, enzyme function, and cellular respiration. This lab was tailored for second semester freshmen who are in their first semester of a three-semester introductory biology course. The first semester focuses on molecular biology, bacterial genetics, and introductory biochemistry. This lab was designed for 500 students split into lab sections of 20. However, this curriculum is easily adaptable to accommodate any number of students.
In this lab, students identify an unknown bacteria using a biochemical method and a molecular method. For the biochemical method, students use a combination of differential growth tests and enzyme tests developed for clinical use. For the molecular method, students PCR amplify and sequence the 16S rRNA gene from their bacteria, then use BLAST to search the bacterial database and identify the species that most closely matches their sequence results for this gene.
This section contains a brief summary of the exercises contained in this lab. More thorough discussion of the materials follow in the General Materials section. The detailed protocol for each exercise is in the Student Section....
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