Question

In eukaryotic flagella, the membrane bound central part is termed as?
A. Shaft
B. Central sheath
C. Axonema
D. Spoke

Answer 1

Hint: Flagella is a long locomotory structure present in many simple organization organisms that help them in locomotion. In some eukaryotic cells, flagella is covered by the cell membrane. In eukaryotes, flagella move in “s” shaped motion.

Complete answer: Cilia and flagella are hair-like outgrowths of the cell membrane.
Cilia are small structures that work like oars and cause the movement of either the cell or the surrounding fluid. Flagella are responsible for cell movement. The microscope reveals that flagella are covered by the plasma membrane. The core of the flagella is known as the axoneme. Axoneme possesses a number of microtubules that are running parallel to the long axis. The axoneme consists of nine pairs of doublets that are arranged radially to peripheral microtubules and a pair of centrally located microtubules. 9+2 array is the type of axonemal microtubule. The central tubules are connected with the help of bridges and it is enclosed by a central sheath which is further connected to one of the tubules of each peripheral doublet by a radial spoke. Linkers connect the peripheral doublets. Both the cilium and flagellum emerge from the basal bodies.

So, the correct option is option C. Axoneme

Note: There are mainly four types of flagella.
1. Monotrichous: It means having one flagellum.
For example, Vibrio cholera
2. Amphitrichous: It means a single flagellum on both sides.
For example, Alcaligenes faecalis
3. Lophotrichous: Tufts of flagella at one or both sides.
For example, spirillum
4. Peritrichous: they have flagella spread across the body except for the poles.
For example, E.coli.