Why is agar a useful substance in the microbiology lab?

Answer 1

Few microbes can degrade agar, so it remains solid during microbial growth. It liquefies at 100 degrees C and solidifies at 40 degrees C. Once the agar has solidified, it can be incubated at temperatures up to 100 degrees C and remain solid.

Answer 2

Chemical agar is a solidifying agent that bacteria can grow on.

A chemically defined media is a media in which the chemical nature of all the ingredients and their amounts are known. These media are also called synthetic media, mainly chemoorganotrophic heterotrophs also can be grown in defined media with glucose as a carbon source and an ammonium salt as a nitrogen source.

Answer 3

1. Microbes Cannot digest the Agar

2.The powder agar dissolved at 100 degrees, a temperature that does not destroy the nutrients

3.It solidifies at low temperatures so temperature sensitive nutrients can be added without detriment to the Agar

4.Does not melt below 100 celcius so it can be used for thermophiles

Answer 4

• (a) non-toxic to most microbes.
• (b) only melts at 100oC, but solidifies at about 45oC (a temperature most bacteria can survive).
• (c) nontoxic to other forms of life.
• (d) stable to sterilization temperatures.
• (e) physiologically inert as very few bacteria have the enzymes for digesting it.

Answer 5

Because agar remains solid during bacterium incubation and generally bacteria cannot break down agar as an energy/carbon source.