Key differences, features, and comparative analysis of Sub-stage and Key event.
| Sub-stage | Key event |
|---|---|
| Leptotene | Chromosomes become gradually visible under the light microscope; they begin to condense. |
| Zygotene | Synapsis — homologous chromosomes pair, forming a bivalent (tetrad); the synaptonemal complex forms between them. |
| Pachytene | Crossing over — exchange of segments between non-sister chromatids at recombination nodules, catalysed by the enzyme recombinase. Bivalents now clearly appear as tetrads. |
| Diplotene | The synaptonemal complex dissolves; homologues separate slightly but stay joined at chiasmata (X-shaped sites of crossing over). |
| Diakinesis | Terminalisation of chiasmata; chromosomes fully condense; spindle assembles; nucleolus & nuclear envelope disappear — marks the end of Prophase I. |
This comparison table is part of the chapter notes for Cell Cycle & Cell Division. Get complete notes, flashcards, active recall sheets, and test prep modes:
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