GENERAL HISTOLOGY

Detailed explanation-1: -A flagellum (/fləˈdʒɛləm/; pl. flagella) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates . Structure of bacterial flagellum.

Detailed explanation-2: -The force for flagellar movement is exerted by the sliding of outer-doublet microtubules driven by the molecular motors, the dyneins. Dynein activity is regulated by the radial spoke/central pair apparatus through protein phosphorylation, resulting in flagellar bend propagation.

Detailed explanation-3: -Typical sperm are “stripped-down” cells, equipped with a strong flagellum to propel them through an aqueous medium but unencumbered by cytoplasmic organelles such as ribosomes, endoplasmic reticulum, or Golgi apparatus, which are unnecessary for the task of delivering the DNA to the egg.

Detailed explanation-4: -Flagella and cillia are the flexible extensions of the plasma membrane of sperm cells. The cell is propelled by the beating of these extensions.