GENERAL HISTOLOGY

Detailed explanation-1: -Safranine is used to stain onion peel cells. This makes them easily observable under a microscope. It imparts a characteristic pink colour to the cells. Methylene blue is used to impart a blue colour to cheek cells.

Detailed explanation-2: -Onion cell slide Prepare a 0.01M Iodine stain two days prior to class. In an operating fume cupboard or well-ventilated area, weigh 15 g potassium iodide and dissolve in 100 mL of distilled water. Add 3 g iodine crystals and stir to dissolve. Iodine dissolves quickly in concentrated potassium iodide solution.

Detailed explanation-3: -The iodine acts as a stain to make the structures in the cell easier to see. Carefully lower a cover slip over the onion skin. Try to avoid trapping air bubbles. Place the slide on the microscope stage.

Detailed explanation-4: -As a biological stain, iodine is useful for studying plant cells because it stains starch blue-black and in animal tissue, it can help in the demonstration of nuclei and cell membranes.

Detailed explanation-5: -Iodine is used in staining cells of an onion peel on the slide due to following reason. *Onion bulb is made up of scaly leaves which store starch granules in their cytoplasm of the cells. *Iodine binds to starch in the granules and develops blue black colour.