Ijmb Model Questions Vol1 2024 Biology Question 2

Practice practical question 2 from the 2024 Ijmb Model Questions Vol1 Biology examination. This question covers Cell Division .

Ijmb Model Questions Vol1 2024 Biology Practical
Topic: Cell Division
Question 2 IJMB_MODEL_QUESTIONS_VOL1 • 2024 • BIOLOGY • practical

A smear of onion root tip cells has been prepared and stained with aceto‑orcein. Using a light microscope, you examined five fields of view, each field containing exactly 100 cells. The numbers of cells observed in each mitotic phase are recorded below: Field 1: Prophase 12, Metaphase 8, Anaphase 5, Telophase 3 Field 2: Prophase 15, Metaphase 7, Anaphase 4, Telophase 2 Field 3: Prophase 10, Metaphase 9, Anaphase 6, Telophase 4 Field 4: Prophase 13, Metaphase 6, Anaphase 5, Telophase 3 Field 5: Prophase 14, Metaphase 8, Anaphase 5, Telophase 2 The cover slip used is 5 µm thick and the area of each field of view is 0.02 mm².

Question Parts

( a )
Calculate the mitotic index (percentage of cells in mitosis) for the whole slide.
( b )
Identify the most frequently observed mitotic phase and explain what this suggests about the cell population in the root tip.
( c )
Using the given field area and cover‑slip thickness, calculate the volume of the smear observed in one field of view. Express your answer in cubic millimetres (mm³) and in nanolitres (nL).
( d )
Suggest two practical improvements that could reduce counting errors in the determination of the mitotic index.

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About This Question

This is Ijmb Model Questions Vol1 2024 Biology Question 2. It is one of the practical questions from the 2024 Ijmb Model Questions Vol1 Biology examination.

The question covers Cell Division .

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