It is important to avoid digging into agar with the loop due to the high risk of cross contamination between different specimens. Contamination renders a petri dish or streak plate unusable. The American Society for Microbiology states that improper loop sterilization also increases the risk of contamination.
According to Boston University, modern streak plate protocol calls for three or four samples per petri dish. Each segment requires a new swab or sterilized loop. The most popular tools used to inoculate agar are cotton swabs and metal loops. Cotton swabs are single-use instruments because they do not withstand flame sterilization. Reusable metal loops require sterilization after every use.
Some scientists prefer to use plastic loops. These resemble metal loops but must be thrown away after each inoculation. Metal needles are another option. Like metal loops, needles require sterilization.
The American Society for Microbiology recommends sterilizing metal loops and needles by passing them through the flame of a Bunsen burner turned to its lowest setting. To sterilize an instrument, insert it into the light blue portion of the flame and hold it there until it glows orange or red. Gradually inserting the loop or needle into the flame prevents sputtering of potentially biohazardous liquids.
Another effective way to sterilize metal loops and needles is to place them in an incineration machine designed for that purpose. This method of sterilization takes less than 10 seconds. However, the incinerator takes several minutes to reach operating temperature.Learn More
Monoecious plants have both male and female flowers on the same specimen, while dioecious plants produce male and female flowers on different specimens. This means that while a monoecious plant may pollinate itself, dioecious plants require a partner to achieve pollination. Most common landscaping plants are monoecious and require no partner for fertilizing their ova.Full Answer >
Aluminum reacts with sodium hydroxide. Sodium hydroxide is otherwise known as lye or caustic soda.
When aluminum and sodium hydroxide come into contact with one another, there is quite a vigorous reaction.Full Answer >
A light microscope uses a focused beam of visible light to magnify objects for observation. It works in a similar way as a refracting telescope but with several minor differences. A telescope uses a large objective lens, because it needs large amounts of light to bring a dim, distant object to a bright focus. On the other hand, a light microscope does not need a large objective lens because it only needs to acquire light from a small area of a thin, close specimen that is well illuminated.Full Answer >
Light microscopes reveal the structures of living cells and tissues, according to HowStuffWorks.com. Using light microscopes, scientists have greatly increased human knowledge in the biomedical science fields. Even as they make strides in available technology, the light microscope continues to provide a powerful tool for scientists.Full Answer >