Igcse Model Questions Vol1 2022 Biology Question 2

Practice practical question 2 from the 2022 Igcse Model Questions Vol1 Biology examination. This question covers Cell Division .

Igcse Model Questions Vol1 2022 Biology Practical

Topic: Cell Division

Question 2 IGCSE_MODEL_QUESTIONS_VOL1 • 2022 • BIOLOGY • practical

A student investigates mitosis in the root tip of an onion (Allium cepa) using the squash technique. After fixing the root tip in Carnoy's solution, staining with aceto‑orcein, and preparing a slide, the student examines a random field of view at 100× objective and records the following numbers of cells in each stage of mitosis. - Prophase: 30 cells - Metaphase: 20 cells - Anaphase: 15 cells - Telophase: 10 cells - Interphase (non‑dividing cells): 125 cells The total number of cells counted in the field is therefore 200.

Question Parts

( a )

Calculate the mitotic index for the root tip sample. Show your working.

( b )

Explain what a high mitotic index indicates about the growth activity of the tissue observed.

( c )

Identify two sources of error that could affect the reliability of the mitotic index obtained and suggest one way to minimise each error.

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About This Question

This is Igcse Model Questions Vol1 2022 Biology Question 2. It is one of the practical questions from the 2022 Igcse Model Questions Vol1 Biology examination.

The question covers Cell Division .

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