Question

Using the staining and counting protocol utilized in this laboratory exercise, design another experiment to test differences in mitotic rates among two populations of cetts (net necessarily limited to plants or to the independent variable used in this lab)? Provide the hypothesis that you would be testing.

Answer 1

1. Take 2 population of cells.
2. Prepare the cells for procedure (If the cells are obtained from the plat material, then it is cleaned. Then the plant material or the animal tissue is cut into small parts and prepared.).
3. Label the populations properly.
4. Treat the cell populations with hydrochloric acid (only for plant cells).
5. Wash with distilled water and dry the specimen using filter paper.
6. Take the specimens of each population and place it in the microscopic slide.
7. Stain the specimens with acetocarmine stain.
8. After 2 minutes, gently squash the specimen while placing the conerslip on top of it.
9. Count the cells undergoing mitosis (prophase(P), metaphase(M), anaphase(A), telophase(T)) and the total cells(N) of both population in the microscopic view.
10. Note the time of a cell to complete metaphase (t) for both cell population.
11. Calculate mitotic index using the below formula.

(NOTE: Steps 4 and 5 are skipped, if the samples are given as cell suspension)

Mitotic index (I)= ](P+M+A+T)/N] * 100

Average length of the cell cycle = (t / I)*100 where t=time duration of metaphase

The difference in mitotic rate can be analysed from the calculated mitotic index and average length of the cell cycle.