media and gram staining

Question 1

what are the 2 types of media used for identifying microorganisms

Answer 1

selective and differential media

Question 2

describe how selective media works

Answer 2

the presence of specific substances allows the growth of certain organisms over others, it selects the growth of specific prokaryotes

Question 3

describe how differential media works

Answer 3

chemicals are used to produce visible changes in colonies that allow identification

Question 4

what does the process of gram staining allow and how does it work

Answer 4

allows you to distinguish between the classes of gram +ve or -ve, according to the cell wall structure, using the retention of crystal violet/iodine complex by gram +ve bacteria

Question 5

what are the limitations of gram staining

Answer 5

not all organisms stain well with gram staining, so other tests must be used for example the organism that causes TB