Ijmb Model Questions Vol1 2025 Biology Question 2

Practice practical question 2 from the 2025 Ijmb Model Questions Vol1 Biology examination. This question covers Cell Division .

Ijmb Model Questions Vol1 2025 Biology Practical

Topic: Cell Division

Question 2 IJMB_MODEL_QUESTIONS_VOL1 • 2025 • BIOLOGY • practical

A sample of onion (Allium cepa) root tip is collected, fixed in Carnoy's solution, stained with aceto‑orcein and a squash preparation is examined under a compound microscope. From a randomly chosen field you count a total of 300 cells and record the number of cells in each stage of mitosis as follows: Prophase – 45 cells, Metaphase – 60 cells, Anaphase – 30 cells, Telophase – 15 cells, Interphase – 150 cells.

Question Parts

( a )

Calculate the mitotic index, expressed as the percentage of cells that are in any stage of mitosis.

( b )

Determine the percentage distribution of each mitotic phase (Prophase, Metaphase, Anaphase, Telophase) relative to the total number of mitotic cells.

( c )

Explain what the mitotic index reveals about the growth activity of the onion root tip.

( d )

Identify two procedural factors that could lead to an under‑estimation of the mitotic index and suggest a method to minimise each factor.

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About This Question

This is Ijmb Model Questions Vol1 2025 Biology Question 2. It is one of the practical questions from the 2025 Ijmb Model Questions Vol1 Biology examination.

The question covers Cell Division .

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