Ijmb Model Questions Vol1 2023 Biology Question 2

Practice practical question 2 from the 2023 Ijmb Model Questions Vol1 Biology examination. This question covers Cell Division .

Ijmb Model Questions Vol1 2023 Biology Practical
Topic: Cell Division
Question 2 IJMB_MODEL_QUESTIONS_VOL1 • 2023 • BIOLOGY • practical

A root‑tip squash of an onion (Allium cepa) was prepared and examined under a light microscope. From a random field of view, 200 cells were counted and classified according to the stage of mitosis observed. The results are shown below: | Stage | Number of cells | |------------|-----------------| | Prophase | 30 | | Metaphase | 25 | | Anaphase | 20 | | Telophase | 15 | | Interphase | 110 | All counts are whole numbers and the total of the five categories equals 200.

Question Parts

( a )
Calculate the mitotic index (MI) for the sample, expressed as a percentage to one decimal place. MI = (total number of cells in mitosis / total number of cells observed) × 100.
( b )
Determine the percentage of cells in each mitotic phase (prophase, metaphase, anaphase, telophase) relative to the total number of mitotic cells. Express each percentage to one decimal place.
( c )
A researcher treats a comparable onion root tip with auxin, a plant growth hormone known to stimulate cell division. Predict qualitatively how the mitotic index and the distribution of mitotic phases would change compared with the untreated sample, and give a brief explanation (maximum two sentences).

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About This Question

This is Ijmb Model Questions Vol1 2023 Biology Question 2. It is one of the practical questions from the 2023 Ijmb Model Questions Vol1 Biology examination.

The question covers Cell Division .

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