Can your draw it out and explain it to me please 36LAB WEEK 7Serial Dilutions, and Plate CountingExercise #2 Pour Plate MethodTo perform the pour plate method, you will use the dilution tubes from the previous schematicand perform the top three agar plates. You will obtain three empty Petri dishes and label them with thedilution factors. Next, you will pipette 1 ml from each of the 9 ml dilution blanks into their respectiveplate. Lastly, you will obtain three molten Tryptic Soy Agar (TSA) agar tubes from the hot water bathand pour one agar tube into each plate. Swirl the agar to mix in the water and make the agar disperseevenly in the bottom of the plate. After the agar hardens, give the plates to the instructor for incuba-tion. Next week you will notice that some of the colonies will be on top and grow larger while onestrapped down in the agar will be small and wedge shaped since they do not have as much freedom forgrowth.DAY 2: RESULTSsEBASthey oddelt sichDE Su borIn the above three circles draw what your pour plates look likeafter incubation and record the count for each platescut situsIn the above three circles draw what your spread plates look likeafter incubation and record the count for each platebacterial cfus/mlRecord your final calculation for the concentration ofbacteria in the original sample tube from last weekSource: Roger L original sample. A second method that is sometimes used is called a pour plate. With this technique,you may pipette a full ml into a molten agar and then pour this agar into an empty Petri dish. YouI can swirl the plate to mix the contents. The molten agar is kept just hot enough so that it does notsolidify but not hot enough to kill the bacteria. Once the agar is poured, it will harden quickly andthe bacterial cells will be dispersed and trapped into the agar and then grow into colonies duringincubation.1 mlExercise #1Spread Plate MethodThe diagram at the bottom of this page shows a schematic of the dilution series we will performtoday using a bacterial culture tube as the original sample. The instructor will walk through the sche-matic on the board to help you calculate out what the dilution factors will be for each bottle, tubeand plate. The instructor will also perform a demonstration to show you how to use the instrumentsconsisting of micropipetters and a vortex machine. Next week you will count the colonies and backcalculate to see what the bacterial concentration was in the original tube.In order to perform the back calculation, you take the number of colonies and multiply it by thedilution factor on the plate. You also want to drop the negative sign off of the exponent since you aregoing back the opposite direction. First, you need to determine which plate is the countable plate. Acountable plate will have between 30 and 300 colonies on it. Any plate with over 300 colonies willbe too crowded or smeared to get a good count and we declare it Too Numerous To Count (TNTC).If a plate has less than 30 colonies on it, then it is discarded for being statistically insignificant. Forexample, if I have a plate that has 237 colonies on it and the dilution factor is 105, then the calculationwould be as follows. The 237 colonies is in the range of 30 to 300 so it is countable. Next, I multiplyit by the dilution factor dropping the negative sign which gives me 237 X 105. This is not correct sci-entific notation so I would report 2.37 X107 cfus/ml as my final concentration. If you struggle withscientific notation, take the 237 colonies and put five zeros after it giving you 23700000. Next, movethe decimal place between the 2 and 3 and then put in the proper exponent of 107. This would tell methat the original culture tube had a bacterial concentration of approximately 23,700,000 cells/ml. Ifyou happen to have more than one countable plate, then you would average them together.10²Sample 99 ml10⁰ = 1 blankPourSpread1 ml10-499 mlblank1 ml10-510-61 ml10-59 mlblank0.1 ml1 ml10-610LAB WEEK 7 Serial Dilutions, and Plate CountingCarial Dilution and Standard Plate Count110-69 mlblank1 ml1 ml0.1 ml10710°9 mlblank1 ml10-80.1 ml35Source: Roger Lightner

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Dilution : The process of lowering a solute's concentration in a solution by increasing the solvent,…