Question

Q.3) Gram positive bacteria

a. Get stained with crystal violet but

the colour is

not retained after washing with

alcohol

b. get stained with crystal violet and

the colour

is retained even after washing with

alcohol

c. Show staining with crystal violet

only in the

presence of alcohol

d. Do not staining reaction with crystal violet​

Answer 1

Explanation:

Bacteria or Monera fall into two groups on the basis of their cell wall structures. For this, a staining technique is used which is known as Gram staining because it was discovered by Christian Gram.

Those who retain the gram stain are called Gram positive and those who don't retain the stain are called Gram negative. Now let's know the procedure in detail:

• First of all, prepare a smear of bacteria.
• Put some drops of crystal violet on the slide.
• After 30s, rinse it with water.
• Then add some drops of Iodine.
• Now again rinse it.
• Now wash it with ethanal (atleast 90%)

Now observe:

1. The one which retain the violet stain is Gram positive bacteria.
2. And the one which don't retain but can retain sarfanin red is the Gram negative Bacteria.

Back to Question:

The answer would be Gram positive bacteria get get stained with crystal violet and the colours retained even after washing with alcohol. It is because alcohol is used to decolourise and to separate the unbound crystal violet drops. And Gram positive bacteria retains them because of thick cell wall.

So, the correct option is:

$\large{ \boxed{ \bf{ \red{Option \: B}}}}$

And we are done !!

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