Read from Megaspore to Embryo Sac
The female gametophyte develops from a megaspore inside the ovule.
Living-system questions are solved by matching a structure or organism to its function, process and stated condition.
Follow development in order
A nucellar cell differentiates into the megaspore mother cell; meiosis produces megaspores; one functional megaspore develops into the 8-nucleate, 7-celled embryo sac. Fertilisation follows, and the ovary later becomes fruit.
Track gamete origins
The megaspore mother cell produces the female gametophyte by meiosis; the microspore mother cell produces microspores that develop into pollen. Wheat typically has one ovule per ovary.
Count nuclear divisions to the embryo sac
The megaspore mother cell undergoes meiosis with two nuclear divisions. The single functional megaspore then undergoes three mitotic divisions. The total is five nuclear divisions, producing the typical eight-nucleate, seven-celled embryo sac.
OlympIQ exam lens
- ✓Nucellus → megaspore mother cell → megaspore → embryo sac.
- ✓Embryo sac: 8 nuclei, 7 cells.
- ✓Microspore mother cell forms pollen lineage.
Keep microspore and megaspore lineages distinct.
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