#Question id: 40410
#Applied Microbiology
Read the following assertion and reason and select the correct option.
Assertion (A): A synthetic chemical like DDT is not considered a "biological material" in the context of biopatents.
Reason (R): Biological materials for patenting purposes must be living organisms or substances naturally produced by them.
#Question id: 40411
#Applied Microbiology
Arrange the correct sequence of color changes observed in a Gram-negative bacterium during the Gram staining process at each step:
After Crystal Violet
After Safranin
After Alcohol decolorization
After Iodine treatment
#Question id: 40412
#Applied Microbiology
Match the Reagents in List-I with their specific role/function in List-II.
| List-I (Reagent) | List-II (Function) |
| (A) Crystal Violet | (I) Mordant (Fixes the dye) |
| (B) Gram's Iodine | (II) Counterstain |
| (C) 95% Ethyl Alcohol | (III) Primary Stain |
| (D) Safranin | (IV) Decolorizing Agent |
#Question id: 40413
#Applied Microbiology
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): After the washing with alcohol (decolorization step), Gram-positive bacteria retain the purple color, while Gram-negative bacteria become colorless.
Reason (R): Gram-positive bacteria have a thick peptidoglycan layer that traps the Crystal Violet-Iodine complex, whereas Gram-negative bacteria have a high lipid content in their outer membrane which dissolves in alcohol.
#Question id: 40414
#Applied Microbiology
- Read the following statements regarding the Gram staining technique.
- Statement I: Heat fixing is done after adding the crystal violet stain to the slide.
- Statement II: Ideally, the iodine solution (mordant) should be kept on the smear for approximately 1 minute.
#Question id: 40415
#Applied Microbiology
Which of the following errors during the Gram staining procedure would most likely cause a Gram-positive bacterium to appear Gram-negative (pink)?