flagellum

Examples of flagellum in the following topics:

• Opisthokonts: Animals and Fungi

  • One common characteristic of opisthokonts is that flagellate cells, such as most animal sperm and chytrid spores, propel themselves with a single posterior flagellum .
  • Most fungi do not produce cells with flagellae, but the primitive fungal chytrids do, suggesting that a common ancestor of current fungal species did have a flagellum.
  • Here is a depiction of a unicellular organism with a flagellum.
  • Flagellum are a typical structure found on opisthokonts, sometimes at only specific points of the a life cycle.

• Chemotaxis

  • Clockwise rotation - breaks the flagella bundle apart such that each flagellum points in a different direction, causing the bacterium to tumble in place.
  • Many bacteria, such as Vibrio, are monoflagellated and have a single flagellum at one pole of the cell.
  • Others possess a single flagellum that is kept inside the cell wall.
  • CheY induces tumbling by interacting with the flagellar switch protein FliM, inducing a change from counter-clockwise to clockwise rotation of the flagellum.
  • Change in the rotation state of a single flagellum can disrupt the entire flagella bundle and cause a tumble.

• Intermediate Filaments and Microtubules

  • Flagella (singular = flagellum) are long, hair-like structures that extend from the plasma membrane and are used to move an entire cell (for example, sperm, Euglena).
  • When present, the cell has just one flagellum or a few flagella.
  • This is an appropriate name because a single flagellum or cilium is made of a ring of nine microtubule doublets surrounding a single microtubule doublet in the center .

• Chromalveolata: Stramenopiles

  • The unifying feature of this group is the presence of a textured, or "hairy," flagellum.
  • Many stramenopiles also have an additional flagellum that lacks hair-like projections .
  • This stramenopile cell has a single hairy flagellum and a secondary smooth flagellum.

• Morphologically Unusual Proteobacteria

  • One daughter is a mobile "swarmer" cell that has a single flagellum at one cell pole that provides swimming motility for chemotaxis.
  • One daughter is a mobile "swarmer" cell that has a single flagellum at one cell pole that provides swimming motility for chemotaxis.

• Contractile Vacuoles in Microorganisms

  • Structure of Euglena: 1 - Flagellum; 2 - Eye spot / Pigment spot / Stigma; 3 - Photoreceptor; 4 - Short second flagellum; 5 - Reservoir; 6 - Basal body; 7 - Contractile vacuole; 8 - Paramylon granule; 9 - Chloroplasts; 10 - Nucleus; 11 - Nucleolus; 12 - Pellicle

• Bryophytes

  • The gametes formed by bryophytes swim with a flagellum.

• Fertilization

  • Fusion between the oocyte plasma membrane and sperm follows and allows the sperm nucleus, centriole, and flagellum, but not the mitochondria, to enter the oocyte.

• Sperm

  • The uniflagellated sperm cells (with one flagellum) of animals are referred to as spermatozoa.

• Chytridiomycota: The Chytrids

  • Their gametes are the only fungal cells known to have a flagellum.