Choose the correct statement in respect to metazoan development:
Choose the correct statement in respect to metazoan development:
Select an option to attempt
Correct Answer: Option D
Explanation
Notch-Delta signalling in lateral inhibition:In Notch signalling during metazoan development:• Notch: a single-pass transmembrane RECEPTOR (type I) — expressed on the surface of the receiving cell.• Delta (and Serrate/Jagged): transmembrane LIGANDS — expressed on the surface of the signal-sending cell.Lateral inhibition mechanism:1. In a field of equivalent precursor cells, all initially express BOTH Notch and Delta.2. Random fluctuations: one cell slightly upregulates Delta → activates Notch in adjacent cells.3. Notch activation → represses Delta in that cell (via Hairy/Enhancer of split).4. Through feedback: one cell becomes 'Delta-high/Notch-low' (neuronal/primary fate); its neighbours become 'Notch-high/Delta-low' (non-neuronal/secondary fate).Key point: Notch and Delta CAN be on the SAME precursor cell, but after fate specification they become DIFFERENTIALLY expressed.Answer: Both Notch (receptor) and Delta (ligand) are cell surface proteins on the same precursor cell; lateral inhibition drives differential expression during fate determination.