PHYLUM: PROTOZOA Locomotory Organs By: AAKRITI
FLAGELLUM (LOCOMOTORY ORGANELLES): . Flagella are the locomotory organelles of flagellate mastigophoran protozoans. They are mostly thread like projection on the cell surface. A typical flagellum consists of an elongated, stiff axial fiber called as axial filament or axoneme enclosed by an outer sheath The axoneme arises from basal granule called as blepharoplast or kinetosome which is further derived from Centrioles. . Blepharoplast lies below the cell surface in the ectoplasm.The region around blepharoplast is called microtubular organizing center that controls the assembly of microtubules.
&tamata laqelium contrarhle Pellicle endoblnam ehlosoplast
. When the axial filament is viewed under an electron microscope 9+2 arrangement can be observed. . The 2 central longitudinal fibers are enclosed by membranous inner sheath The 2 central Tongitudinal fibers are surrounded by g longitudinal peripheral doublets (each with microtubules A and B) which form a cylinder between the inner and the outer sheath . Each peripheral paired fiber is connected to the internal membranous sheath by radial spokes. .Each peripheral doublet also has pairs of arms directed towards neighboring doublet.
Microtubules In Cilia And Flagella outer dynein arm radial spoke inner sheath central singlet nexin microtubule plasma membrane inner dynein arm A microtubule Bmicrotubule outer doublet microtubule 100 nm .92 arrangement of microtubules; outer doublets Cross-linking proteins Ciliary dynein
These arms are made of the protein called as dynein. The arms create the sliding force . The peripheral doublets are surrounded by an outer membranous sheath called as protoplasmic sheath, which is an extension of the plasma membrane Some flagella also bear lateral appendages called as flimmers or mastigonemes along the length of the axoneme above the level of the pellicle
Types of Flagella: Number and arrangement of flagella vary itn Mastigophora from one to eight or more. Free living species usually have one to eight flagella whereas the parasitic forms may have one to many flagella Flagella are classified based on the arrangement of lateral appendages and the nature of the axial filament.
Stichonematic Pantonematic Acronematic Pantacronematic Anematic Eg: Euglena, Astasia E: Peranema, Monas Eg.Chlanydomonas Eg: Uolus Eg: Cryptomonas
Stichonematic: Only one row of lateral appendages occurs on the axoneme up to tip.Eg:Euglena, Astasia Pantonematic: Two or more rows of lateral appendages occur on the axoneme. Eg:Peranema, Monas Acronematic: Lateral appendages are absent and axoneme ends as a terminal 'naked' axial filament. Eg:Chlamydomonas, Polytoma Pantacronematic: Flagellum is provided with two or more rows of lateral appendages and the axoneme ends in a terminal naked axial filament. Eg:Urceolus Anematic: In some cases the flagella is simple without any lateral appendages and a terminal naked filament. Eg:Chilomonas, Cryptomonas
CILIA (LOCOMOTORY ORGANELLES): surface of the body. ciliate protozoan. Cilia greatly resemble the flagella in the basic structure .Cilia are short hair like structures present all over the * They may be also confined to specitic regions of the . Cilia help in locomotion as well as in food collection. . The major difference between the flagella and the cilia is that cilia are smaller compared to the flagella. Cilia arise from the kinetosome. Cilia consist of an axial filament called as axoneme surrounded by the protoplasmic outer sheath
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