Posts Tagged ‘Demonstration’
Using A Micropipette: Youtube demonstration
| Demonstration for using a Micropipette. Must watch! |
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Chemotaxis- Bacterial Movement!
Still don’t have any faster way to get online (again posting from Nokia N72 using Vodafone GPRS!) but I’m expecting to get a broadband connection installed at my home by this Monday.
And I discovered the answer to that question in that book itself. Here’s the solution-
For distinguishing a Procaryote from Eucaryote without using a Microscope, the phenomena of “Chemotaxis” may be considered.
Bacteria, falls under Procaryotes shows movement towards certain chemicals known as “Attractants” also they show movement away from some chemicals, named as “Repellents”.
This type of behavior is shown by bacteria only.
Demonstration:-
1:-Take a capillary tube, fill it with some proper attractant & place it over a bacterial suspension. On diffusion of attractant from the end of the capillary, bacteria will swim up that capillary tube.
Number of bacteria in that capillary tube will determine the strength of attractant & rate of chemotaxis.
2:- If bacteria are placed in the centre of a petri dish of a semisolid agar containing an attractant, the bacteria will exhaust the local supply & then swim outward following the attractant gradient they have created. Result is expanding ring of bacteria.
And when a disk of repellent is placed in a petri dish of semisolid agar & bacteria, the bacteria will swim away from repellent, creating a clear zone around the disk.
