Cryo-ET of Chlamydomonas cells. A and B, Longitudinal (A) and cross-sectional (B) tomographic slices through a Chlamydomonas cilium showing the central pair complex (CPC), doublet microtubules (DMTs), and ciliary membrane (M) with the extracellular glycocalyx (G). White brackets in (A) denote a single 96-nm axonemal repeat, which contains two radial spokes. C and D, Subtomogram average of the 96-nm axonemal repeat unit displayed as an isosurface rendering (C). ODA, outer dynein arm; N-DRC, nexin-dynein regulatory complex; I1α/I1β/ICLC, α- and β-heavy chain and intermediate/light-chain complex of the I1 dynein; IDA/a-e and g, inner dynein arm isoforms; RS, radial spoke. Enlarged bottom-view of the N-DRC (D), indicating positions of protein subunits (adapted from Gui et al. (2019). E, Architecture of the ciliary central pair complex viewed from proximal to distal, highlighting the color-coded and labeled projections of the C1 and C2 microtubule (adapted from Fu et al. (2019). F, Tomographic slice through a cryo-FIB milled Chlamydomonas cell body. M, mitochondrion; C, chloroplast; T, thylakoid; S, starch granule; R, ribosomes; V, vesicle. Arrowheads highlight detailed molecular structures, including ATP synthases in the mitochondrion, oxygen-evolving complexes in the thylakoid membrane, contact sites between the outer and inner chloroplast membranes, and a vesicular coat. Scale bars = 100 nm in B (valid for A as well), 200 nm in F.