Practice question

Cilia and flagella share fundamentally conserved ultrastructure despite differing length, number and beat pattern across eukaryotes. Both contain nine peripheral microtubule doublets encircling two central singlets, designated 9+2 axoneme, anchored by basal body derived from centriole. Dynein arms generate sliding force hydrolyzing ATP, converted to bending by nexin links and radial spokes. Variations in waveform result from regulatory proteins, not core architecture. Protein composition overlaps heavily with tubulin and dynein, but defining similarity remains internal axonemal organization conserved from protists to mammalian epithelia.