Chemotaxis on the Move – Active Learning Teaching Tool
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Author:
Ann H. Williams1,*
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Published 20 December 2010
- *Corresponding author. Mailing address: Biology Department, University of Tampa, Box 3F, 401 W. Kennedy Blvd., Tampa, FL 33606. Phone: (813) 257-3994. Fax: (813) 258-7496. E-mail: [email protected].
- Copyright © 2010 American Society for Microbiology
Abstract:
In Microbiology courses, concepts such as chemotaxis can be difficult to visualize for students. Described here is a short visual playacting activity where students simulate E.coli moving towards an attractant source using a biased random walk. This short interactive activity is performed in the lecture course of General Microbiology that contains mostly Biology major juniors or seniors prior to the lecture on the subject of chemotaxis and flagellar movements. It is utilized to help students (class of 30–40) understand and visualize the process of chemotaxis and the concepts of random walk, biased random walk, runs, tumbles and directed movement of flagella in response to attractants and repellents.
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Abstract:
In Microbiology courses, concepts such as chemotaxis can be difficult to visualize for students. Described here is a short visual playacting activity where students simulate E.coli moving towards an attractant source using a biased random walk. This short interactive activity is performed in the lecture course of General Microbiology that contains mostly Biology major juniors or seniors prior to the lecture on the subject of chemotaxis and flagellar movements. It is utilized to help students (class of 30–40) understand and visualize the process of chemotaxis and the concepts of random walk, biased random walk, runs, tumbles and directed movement of flagella in response to attractants and repellents.

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Author and Article Information
-
Published 20 December 2010
- *Corresponding author. Mailing address: Biology Department, University of Tampa, Box 3F, 401 W. Kennedy Blvd., Tampa, FL 33606. Phone: (813) 257-3994. Fax: (813) 258-7496. E-mail: [email protected].
- Copyright © 2010 American Society for Microbiology
Figures
Demonstration of random walk.
Each star is a student and each will perform a random walk. The random walk for only three students is shown (dark black stars). Each student performed four runs (arrows) and four tumbles (circles) with the black circle tumble being the end location of the student. Each tumble can result in movement in a new direction and all runs are five steps, regardless of direction the student is facing. For all three students, the end tumble (black circle) is still not past the three-quarter line towards the apple pie.

Click to view
FIGURE 1
Demonstration of random walk.
Each star is a student and each will perform a random walk. The random walk for only three students is shown (dark black stars). Each student performed four runs (arrows) and four tumbles (circles) with the black circle tumble being the end location of the student. Each tumble can result in movement in a new direction and all runs are five steps, regardless of direction the student is facing. For all three students, the end tumble (black circle) is still not past the three-quarter line towards the apple pie.
Demonstration of biased random walk.
Each star is a student performing a biased random walk towards the apple pie. The biased random walk is shown for only three students (dark black stars). Each student performed four runs (arrows) and four tumbles, with the black circle tumble being the end location of the student. The student will always tumble after a run but if they are facing apple pie, they run for ten steps; if facing away from apple pie, run for two steps; or if facing in between, run for five steps. More of the students have migrated towards the apple pie in the biased random walk than in the random walk. This is evident by two of the three students (black circle end tumbles) reaching past the three-quarter line towards the apple pie.

Click to view
FIGURE 2
Demonstration of biased random walk.
Each star is a student performing a biased random walk towards the apple pie. The biased random walk is shown for only three students (dark black stars). Each student performed four runs (arrows) and four tumbles, with the black circle tumble being the end location of the student. The student will always tumble after a run but if they are facing apple pie, they run for ten steps; if facing away from apple pie, run for two steps; or if facing in between, run for five steps. More of the students have migrated towards the apple pie in the biased random walk than in the random walk. This is evident by two of the three students (black circle end tumbles) reaching past the three-quarter line towards the apple pie.