Question

Bacterial flagella are made of
A. Carbohydrate
B. Lipid
C. Protein
D. Amide

Answer 1

Hint: A biological macromolecular nano-machine for locomotion in bacteria is known as flagellum. A membrane embedded molecular motor rotates a long helical filament that works as a propeller and helps bacteria in driving through the liquid environment.

Complete answer:
Carbohydrates are ketones or polyhydroxy aldehydes . They are the main components in the cell wall. Lipids are major structural components of plasma membranes or biological membranes. Amides are obtained by the substitution of the hydroxyl group of a carboxylic acid with the amino group.
The flagellum is composed of around 30 different proteins with copy numbers ranging of a few thousands and is made by self-assembly of those proteins. By changes in the chemical environment, the helical filament can be transformed into different distinct super coiled forms such as single, mechanical forces or amino acid mutations. The axial portion of the bacterial flagellum involves several substructures: the hook, the hook-filament junction, the rod, the long helical filament and a cap at the filament tip. At the primary sequence level, although the axial component proteins are dissimilar, they share structural characteristics that are common. The central portions of their amino acid sequences are hyper variable whereas carboxy- and amino-terminal parts contain highly conserved segments. In their monomeric form, they possess large, natively-disordered terminal regions which are essential in controlling and mediating inter-subunit interactions.

Hence, the correct answer is option (C).

Note: Combining the X-ray diffraction and the single particle image analysis by cryo-EM— in the recent structural studies have given insights into molecular mechanisms of polymorphic ability, self-assembly and super coiling open way for construction of different flagella-based systems for applications in bio- or nanotechnology and vaccination.