Cilia+and+Flagella



**Cilia and Flagella**
// -**Cilium (pl. Cilia)** // A microscopic, hair-like projection on the surfaces of some cells. Extends 5-10 micrometers. Cilia are found in Eukaryotes and are rarely found in plants and grow on the outside surface of the cell. they are rarely found alone, they are in large numbers and work in cordinated waves across the surface of the cell to perform its function. - In protists cilia are used for locomotion and moving water over thei surface.

- A second type of cilia is called the primary cilia, Eukaryotic cells only have one primary cilia on them, and they rarely don't have one. Primary cilia were discovered in 1898 however it wasn't untill very recently however that their importance was known. Primary cilia are known to be important in chemical sensation, signal transduction, and control in cell growth. - Non-primary cilia are called motile cillia, and primary cilia are also known as non-motile cilia

Common uses of motile Cilia - Used in the lining of the trachea in order to filter out dirt, chemicals, bacteria, and many other thing that could be potentialy harmful to the body out of the lungs. They are also used in order to keep the mucus in the nose and throat area from falling back into the lungs. - In female mammals cilia is also used to sweep the ovum from the ovary to the uterus - Primary Cilia are used for signal transduction and regulation of cell growth - An example of primary cilia use is on the photoreceptor cells of the eye, and connecting it to the other cells in the eye.

- **// Flagellum (pl. Flagella) //** A tail-like structure that projects from the cell body of certain prokaryotic and eukaryotic cells.

Flagella Flagella are long, whip-like extensions off the cell. They are made of protein and rotate like propellers so the cell can swim through liquids such as a body of water or body fluids of larger organisms. flagella are found in bacteria, archaea, and eukaryotes. It is helical and has a bend just outside the outer membrane called the hook. The rod in the picture below runs between the hook and the basal body, the anchor of the flagella, and passes through protein rings in the cell's membranes. [|Gram-positive] organisms have 2 basal body rings, one in the peptidoglycan, cross-linked complex of polysaccharides and peptides, and one in the cell membrane. [|Gram-negative] organisms have 4 rings. The L ring associates with lipopolysaccharides, P ring associates with peptidoglycan layer, and MS ring is attached to the cell membrane. The filament is a bundle of nine fused pairs of [|microtubules]surrounding two central single microtubules. A flagellum is driven by a rotary engine made of protein. It is located at the flagellum's anchor point on the inner cell membrane and [|FliG] acts as the on-off switch. The engine is powered by the flow of protons across the cell membrane due to a concentration gradient. The rotor transports protons across the membrane, and is turned in the process. The rotor by itself can move up to 17,000 rpm, but with a filament attached it will only reach up to 1,000 rpm.



Cilia Vs. Flagella Although cilia and flagella are structurally identical, they do have one major difference: their movement pattern. as seen in the diagram below, flagella move in a propeller motion while cilia move in a back and forth motion.