The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane—more acidic outside the cell than inside the cell. In this bacterial cell, phosphate transport is an example of:

#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:

1. After Crystal Violet

2. After Safranin

3. After Alcohol decolorization

4. After Iodine treatment

#Question id: 40412

#Applied Microbiology

Match the Reagents in List-I with their specific role/function in List-II.

#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

1. Read the following statements regarding the Gram staining technique.
1. 1. Statement I: Heat fixing is done after adding the crystal violet stain to the slide.
2. 1. 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)?