- Naturvetenskapsprogrammet (före 2011) Årskurs 3
- Biologi B
Antibakteriella substanser - Labbrapport i Biologi B (på engelska)
En laborationsrapport på engelska som undersöker antibakteriella substanser - dvs. hur vissa ämnen kan ha samma effekt som antibiotika på bakterier och bakteriernas tillväxt.
hon tyckte att den var mycket bra och gav betyget MVG.
- Materials and Method
• Bacteria from an agar plate or a liquid containing culture medium. (E.Coli 12 K12)
• NA-plates (Nutrientagar)
• Rackla(Swedish), T-alcohol, Lamp and matches
• Heating cabinet (37°C)
• An ependorf stick with 1 cm³ 0,9 % NaCl-solution.
• Grafting needle
• Pipette out of plastic
• Tweezers, Cotton
• Teaspoon, pen, small magnet
• Small filtering papers, about this size О (not necessary )
1. Prepare sterile nutrient agar.
- 6.9 g agar powder
- 300 ml distillated water
Put the water in a cub over a heating plate with a small magnet in it. Then slowly pour the agar powder in the water under the constant stirring done by the magnet spinning. When finished pouring all of it, take the small magnet out with a teaspoon. Put a small piece of cotton on top of the cup. Then put the cup with agar solution in a microwave for a couple of minutes. When it starts to bubble, take it out and let it cool for some minutes till you are able to hold the cup with your bare hands without hurting.
2. Take out the cotton and then Flambera (Swedish) the mouth/opening of the cup and then pour the solution on the sterile NA-plate. Then close the lid and let the solution cool till it is firm like jelly.
3. Take about 1-2 mm² of the bacteria with the grafting needle and place it in the 2ml NaCl solution with the help of the ependorf stick. Mix it thoroughly. Then take 5 ml of the solution and smear it all over the agar plate, with the help of the racklan(Swedish) , that first has to be flamberat(Swedish) so it becomes sterile.
4. Then there is 2 ways of how you can put the four chemicals on the agar.
a) Divide the agar- plate in four sections from beneath with a pen. Then drill four holes in the agar in each section with the pipette. After doing so, you pour the different substances in each hole. It’s highly recommended that you write with pen beneath each section what substance is in the hole.
b) Divide the agar-plate in four sections from beneath with a pen. Take four of the small, round filtering papers in the microwave for about 30 sec to make it somewhat more sterile. Then flambera (swedish) the tweezers and use it to smear the papers with each four substance. After this you simply put them on each section, also here its recommended that you write beneath the agar plate what kind of substance it is on the paper.
5. This is the last and simplest step. Put the agar-plate upside down (to prevent ventilation) in the heating cabinet for about a day or so... Köp tillgång för att läsa mer