Q. An organelle with an internal cross-section showing characteristic array is the
Solution:
Cilia and flagella are long, motile, cylindrical projections of the cell membrane. The core of the cilia and flagella is called as axoneme. Axoneme of Both cilia and flagella, in a cross-section exhibit, a structure of , i.e., microtubules doublets on the periphery and central microtubules. In eukaryotes, it is composed of tubulin protein. Both cilium and flagellum are covered with a layer of plasma membrane.
Diagram showing axoneme of cilia and flagella
They arise from centriole like structures called basal bodies which, possess a number of microtubules running parallel to the long axis, in an arrangement of , i.e., nine triplets in the periphery without any microtubules in the centre, unlike the arrangement found in cilia and flagella.

Diagram showing axoneme of cilia and flagella
They arise from centriole like structures called basal bodies which, possess a number of microtubules running parallel to the long axis, in an arrangement of , i.e., nine triplets in the periphery without any microtubules in the centre, unlike the arrangement found in cilia and flagella.