Question

Assuming that you want to see metaphase chromosomes of onion roots, how do you design an experiment to see as many metaphases as possible?

Answer 1

Onion Roots are used in the experiment as cells are rapidly undergoing mitiosis in the meristem region. This  region in the root tip is the actively growing region and thus the mitotic index is high

Step 1 : Cut .5mm of no. of root tips and place them in a watchglass

Step 2 Add some HCL and stain to the root tips followed by aceitic acid stain

Step 3 Gently heat for 5 mins to evaporate the additional liquid.

Step 4 Transfer the stained roots to slide and cover with cover slip

Step 5. use a peice of paper to blot dry and apply pressure so the root tip forms a thin layer.

Step 6: place it under a microscope and observe.

Step 7: Find the area with active multiplication using 10X magification

Step 8 Switch to the 40X objective to make closer observations.

What we should observe is cells at different stages of the replication cycle.