Waec Model Questions Vol1 2020 Biology Question 2

Practice practical question 2 from the 2020 Waec Model Questions Vol1 Biology examination. This question covers Cell Division .

Waec Model Questions Vol1 2020 Biology Practical

Topic: Cell Division

Question 2 WAEC_MODEL_QUESTIONS_VOL1 • 2020 • BIOLOGY • practical

A sample of rapidly growing onion (Allium cepa) root tip is prepared for microscopic observation. The slide is examined using a 40× objective and a 10× eyepiece (total magnification 400×). In five randomly selected fields of view a total of 200 cells are counted. The numbers of cells observed in the four phases of mitosis are: Prophase – 30 cells, Metaphase – 20 cells, Anaphase – 10 cells, Telophase – 5 cells. The remaining cells are in interphase.

Question Parts

( a )

Calculate the mitotic index, expressed as a percentage of cells in mitosis.

( b )

Determine the percentage of cells in each individual phase of mitosis (relative to the total number of mitotic cells).

( c )

From the percentages obtained, which phase of mitosis appears to occupy the longest period of time? Give a brief explanation.

( d )

Suggest one possible source of error that could affect the accuracy of the mitotic index and propose a method to minimise this error.

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About This Question

This is Waec Model Questions Vol1 2020 Biology Question 2. It is one of the practical questions from the 2020 Waec Model Questions Vol1 Biology examination.

The question covers Cell Division .

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