Meiosis is a process that includes reduction division. The cells that carry out meiosis in the male reproductive organ of plants are known as pollen mother cells.

Figure 2.1 shows photomicrographs of three different stages of meiosis in pollen mother cells from Lilium, a lily plant.

Figure 2.1, photomicrograph A: a pollen mother cell containing two separate clusters of darkly stained, condensed chromosomes, one tightly clumped cluster in the upper part of the cell and a second, slightly less condensed cluster below it, with no dividing wall visible between them.

Figure 2.1, photomicrograph B: a pollen mother cell with a new cell wall partly formed across its middle, separating two daughter nuclei, each containing a small clump of condensed chromosomes in the corner furthest from the dividing wall.

Figure 2.1, photomicrograph C: a pollen mother cell containing a single mass of condensed, tangled chromosomes roughly at the centre of the cell, with faint thread-like spindle fibres visible around it.

Name the stages of meiosis shown in cells A, B and C in Figure 2.1.

2(b)Meiosis Genetic DiversityMedium3 marks

Homologous chromosomes pair up and then separate into different daughter cells during meiosis. Explain what is meant by a homologous pair of chromosomes.

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2(c)Meiosis Genetic DiversityMedium3 marks

Explain the need for reduction division to occur during meiosis.

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