Ijmb Model Questions Vol1 2019 Biology Question 2

Practice practical question 2 from the 2019 Ijmb Model Questions Vol1 Biology examination. This question covers Cell Division .

Ijmb Model Questions Vol1 2019 Biology Practical
Topic: Cell Division
Question 2 IJMB_MODEL_QUESTIONS_VOL1 • 2019 • BIOLOGY • practical

You are investigating the mitotic activity of root tip cells of Allium cepa (onion) using a squash preparation. After staining the preparation with aceto‑orcein, you examined a random field under a light microscope (1000× total magnification) and recorded the following numbers of cells in each stage of the cell cycle: - Prophase: 30 cells - Metaphase: 45 cells - Anaphase: 15 cells - Telophase: 10 cells - Interphase (non‑dividing cells): 200 cells Answer the questions that follow.

Question Parts

( a )
Calculate the mitotic index for the sample. Express your answer as a percentage to two decimal places.
( b )
Determine the percentage of cells that are in metaphase relative to the total number of cells observed. Give your answer to one decimal place.
( c )
The normal mitotic index for healthy onion root tips lies between 2 % and 5 %. Based on your calculation in (a), discuss whether the sample appears to be undergoing normal cell division or is possibly affected by a mutagenic agent. Support your argument with reference to the data.
( d )
Suggest two modifications to the experimental procedure that could improve the accuracy of the mitotic index determination.

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About This Question

This is Ijmb Model Questions Vol1 2019 Biology Question 2. It is one of the practical questions from the 2019 Ijmb Model Questions Vol1 Biology examination.

The question covers Cell Division .

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