S-STEM Scholar Dung Le's Blog

1. What is  micropipette? The micropipette is used to transfer small amounts (< 1 ml) of liquids. The scales on micropipettes are in microliters (1000 !l = 1 ml). The brand of micropipettes we will be using is made by Rainin and called a "Pipetman". These are very expensive, delicate instruments costing $250-300 apiece. We have four sizes identified by the number on the round button on the plunger. The value is the maximum volume in microliters that can be transferred with that size pipette. They are used in conjunction with disposable sterile plastic tips. 2. The limits of micropipette? The limits are: - P10: 1.0 - 10.0  μm - P20: 2.0 - 20.0  μm - P200: 20 - 200  μm - P1000: 200 - 1000  μm Look at the front face of the pipet and you will see a window with three digits inside. The diagram below shows the MAXIMUM value that can or should be dialed in on each size pipet. To exceed these values will put the pipet out of calibration. Beside each "window" ...

     1. Materials - Crystal violet (primary stain) - Gram's iodine (mordant, to fix crystal violet in the cell wall) - Ethanol or Acetone (decolorizer) - Safranin (secondary stain or counterstain) - DI Water  - Microscope slide 2. Procedure - Place a small drop of bacterial sample on a slide. Heat fix the bacteria to the slide by passing it through the flame of a Bunsen burner three times. Applying too much heat or for too long can melt the bacteria cell walls, distorting their shape and leading to an inaccurate result. If too little heat is applied, the bacteria will wash off the slide during staining.   - Use a dropper to apply the primary stain (crystal violet) to the slide and allow it to sit for 1 minute. Gently rinse the slide with water no longer than 5 seconds to remove excess stain. Rinsing too long can remove too much color, while not rinsing long enough may allow too much stain to remain on gram-negative cells. ...

My name is Dung Le, and I have been living in the U.S.A for 2 years ago and this is my 2nd year to studying in Glendale Community College.   My academic  long-term goal is become an Pharmacist, and my short-term goal is Bio-chemistry. I love reading cookbooks,  so  they help me to control time, temperature, technique and equipment to make a cookie or brownies.  Besides, I love working in the lab also. I believe that I work in lab field of STEM- TRAIN, I can gain knowledge about lab skill and biology. They will help me to get more experience and keep my passion to achieve my goal. Lab working which is the way to help me to find my interesting. Nice to meet and work with all of you here!!! Have a good day!