Question

~~7.   Describe the different cultural characteristics identified when you use agar plates,    agar slants, and nutrient broth.

Answer 1

Agar plates -

An agar plate is a petri dish containing agar as a solid growth medium and nutrients used to culture organisms. Colonies can be characterised by

Size , shape, texture , elevation , pigmentation , effect on growth medium .

It can be used to identify the bacteria .

The swab from the bin is directly spread on to the nutrient broth.

Agar slant - it's a screw capped culture tube partially filled with agar plus nutrients . To make it a slant the agar is allowed to cool at an angle . This makes sure that the surface area for the bacteria to grow increases. Some very important point to observe is the pattern of growth some may grow like staphylococcus aureus on the line of inoculation. Or some other like bacillus subtilis follow spreading growth pattern.

Nutrient broth - it is medium which supports the growth of non - fastidius organism. It contains 0.5 % peptone - provides organic nitrogen . 0.3% of yeast extracts and Many nutrients.