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Taxi - movement of bacteria to the food

version (21.5 KB) by Shmuel Ben-Ezra
Friendly user-interface simulating the chemo-taxis movement of biological systems


Updated 23 Nov 2008

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How do bacteria find their way to the food ? many biological systems use the chemo-taxis algorithm to improve their conditions and hence, their chance to survive. Chemo-taxis in general refers to movement influenced by chemical properties of the medium. In this model, we have a group of independent cells in 2-dimensions. Each cell moves in a straight line in random orientation until it tumbles. When it tumbles, the cell gets a new and random direction for propagation, independent of the past. Tumbles occur in some rate of events per unit time. The cell can regulate its tumbling-rate. Furthermore, the cell can detect and remeber local food concentartion. The chemo-taxis algorithm is as follows: If the cell detects a positive change in food concentartion (the cell is happy) - it lowers the tumbling-rate (less tumbles per second, movement in longer straight lines). If the cell detects a negative change in food concentration (the cell is sad) - it raises the tumbling-rate. If the cell detects no change in food concentration - the tumbling rate returns to some default, normal value of tumbling-rate (this is the adaptation mechanism).

Cite As

Shmuel Ben-Ezra (2020). Taxi - movement of bacteria to the food (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (5)

Simple but educative

can anyone please guide me to good resources about this subject. i understand the theory but i cant understand where can i find an algorithm to base my work on it, also i am wondering if i can use the probability to control the bacteria movements and how, i need to do a program with the same idea but much simpler

waled altememy

waled altememy

John D'Errico

Its a simple biased random walk for multiple particles. But its interesting, of some educational value, and has a fairly well done interface. (Although not perfect, as the main set of axes were partially covered by the edit boxes for me. Probably a problem with units on the uicontrols.) The help was not bad, though missing a few items. For example, I wondered what the different colors in the plot meant. My guess is the colors just make it pretty to look at, and help you to follow a single bacterium around the figure. More white space in the help would have made it more readable too. Its simply too dense to read easily as is. Finally, its not entirely obvious to me that the fixed magnitude of velocity, but random directional resets, etc., truly form a good model for bacterial motion.


Graphically enhanced to provide the user with better control and to display the evolution of the system over time.

Help menu added, describing theory, algoeithm and usage of application.

MATLAB Release Compatibility
Created with R14SP3
Compatible with any release
Platform Compatibility
Windows macOS Linux