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Micro-Lab
Microbes in the environment
Question | Answer |
---|---|
What quantity of agar will you need to add? | 1.28 g |
What effect does the agar have on the culture medium? | It solidifies the medium |
To what temperature will it have to be heated? | 100 degrees celcius |
Why is it necessary to keep the flask at an angle through this procedure? | To minimize contamination from the air |
Why is the swab first moistened in sterile water before sampling a dry surface? | the swab must be moist to adequately pick up microbes. |
What is human body temperature in degrees celcius? | 37 degrees celcius |
Why is condensation on the agar undesirable? | Bacteria will be in a liquid suspension instead of forming discrete colonies and it will spread the microbes on the surface |
What is the use of Petri plates in microbiology? | They provide a large surface area for solid culture media in an easily stored container |
What are bacteria using for nutrients in nutrient agar? | Peptone and beef extract |
What is the purpose of the agar? | The agar is the solidifying agent. |
Why is agar preferable to gelatin as a solidifying agent in culture media? | 1. It liquefies at 100 degrees Celsius and stays in a liquid state until cooled to 40 degrees Celsius. 2. Once hardened, it stays solid up to 100 degrees Celsius. 3. Few microbes can metabolize the agar, so it remains solid. |
Did all the organisms living in or on the environments sampled grow on your nutrient agar? Why or why not? | No because we didnt satisfy all the nutritional and environmental requirements |
How could you tell whether the turbidity in your nutrient broth was from a mixture of different microbes or from the growth of only one kind of microbe? | By sub-culturing the nutrient broth onto the surface of a nutrient agar plate. The plate will create discrete colonies & if they differ u can tell. |