The whips is a Organite ensuring the mobility of a cell. Commun run with the Eucaryote S and the Procaryotic S, it is a cytoplasmic prolongation of which the structure is made up of Protéine S complexes.

At the Procaryotic S, it comprises three parts: the basal body, the hook and the filament. At the Eucaryote S, it comprises fibrillary proteins (Microtubule S) and associated proteins able to involve a movement.

Whips at the procaryotes

At the Procaryotic S, 40 Gène S are necessary for the assembly and the operation of whip. The assembly of whip is held in a sequential way, from the internal part towards most external: insertion of the disc M in the membrane then disc S, addition of the stem and its cap, addition of the discs P and L, addition of the hook and completion, autoassemblage of the flagellar filament (by polymerization of Flagelline) and finally addition of the Protein S of motility.

At the Bacterium S mobiles, there exist various flagellar types inducing of variable displacements which one will call ciliatures:

  • only one whips polar = ciliature monotriche has (right)
  • several whip polar = ciliature lophotriche B (right + collapses)
  • one whips with each pole = ciliature amphitriche C (zigzag Net)
  • of whip surrounding the bacterium = ciliature péritriche D (whirling)

Whip have a structure hélicale. They cling with their engine, the basal body, with the cellular wall and the cytoplasmic membrane. Each whips is a semi-rigid body which turns like a propeller. The energy of rotation of the basal body comes from a force proton-motor coach. A rotation requires 1.000 protons. The Bactérie S move at a speed 60 cellular lengths a second. That is equivalent to approximately 0.00017 km/h. Nevertheless, it is very fast, the Guépard, reached a maximum speed of 110 km/h, which is equivalent to 25 lengths a second.

One will note also the antigenic character of whip called Antigène S H or flagellar useful for the bacterial Sérotypage.

Whip are very difficult to observe directly, because they are very small (on average 15 to 20 µm) One can highlight them thanks to the medium mannitol mobility because whip them make the bacteria mobile.

Ultrastructure of whips procaryotic

Broadly whips it procaryotic consists of three parts:
  • the flagellar filament : It is longest and most obvious, it extends from cellular surface: it is this part which is highlighted during colorings and observation in optical Microscopie. It is a hollow roll and rigid made up of many monomers of only one Protéine: the Flagelline. There exists however whip complex, made up of several distinct proteins. These monomers seem in all the cases to borrow the central channel to be finally assembled at the distal end.

  • the hook : It is of a diameter higher than the filament and is located very close to cellular surface. It makes the connection between the basal body and the flagellar filament. Its role is to transmit the movement of the basal body to the filament.

  • the basal body : it is hidden in the cell and its structure differs from the negative bacteria positive Gram and Gram. One can define it as a small needle stem inserted in a system of rings, the whole hidden on the level of the plasmic Membrane and the wall.

    • At the negative Gram S, one finds four rings which are attached to the needle stem:
      • Two external rings whose role is to stabilize and to fix the whole of the structure at the cellular body. The ring L is related to the external Membrane and P is related to the Peptidoglycane.
      • Two rings internal M and S which turns, it is acted in fact of the flagellar engine, it is them which while turning transmit the movement to the filament. M is related to the plasmic membrane.
Whips is sometimes covered with a membrane, derived from the external in certain cases, or completely original membrane in other cases.
    • At the positive Gram S, one finds only two rings:
      • an external ring related to the peptidoglycane.
      • a ring interns, which plays the driving part of , it is related to the plasmic membrane.

The internal rings (or rotor ) are able to turn in the two directions, which make it possible the bacterium to change sens.
The external rings (or stator ) do not turn, they have as a role to stabilize the whole of the flagellar structure.

As one could expect it, the structure of whips very different at is archées, near to the pili of the type IV of the eubacteries. For example, there is no central channel (what implies in particular that the new monomers of flagelline are added at the proximale end).

Whips at the eucaryotes

August 1st The structure of whip cells Eucaryote S is appreciably different, and is characterized in particular by the presence of a sleeve mitochondrial, a length largely more important: up to 200 µm (against 14 µm in the bacteria), moreover the biochemical structure of whips differs: there is no Flagelline but one notes the presence of Microtubule S. the embedding of whips in the membrane is done by tubular invagination.

Formation of whips at the time of the Spermiogenèse

For the human Spermatozoon S, they are formed from one of the centrioles of the round Spermatide. These two Centriole S migrate to the future posterior part of the cellule.
The centriole nearest to the core is known as proximal or juxtanucléaire and furthest away from the core is known as distal. It is the latter which will be at the origin of whips. It gives rise to the microtubules constituting the axis of whips. The springing of whips is the coll.

See too

  • the lashes.

  • Pili (or fimbriae ) unicellular
  • Standard cellular or organizations having one whips:
  • Caryomastigonte

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