Cilia and Flagella
Distribution:
Cilia:
- On protozoa (eg. Paramecium, Vorticella and Stentor)
- Respiratory tract (eg. trachea)
- Oviductus.
Flagella:
- On algae, a number of protozoa (eg. Euglena and Chlamydomonas) and a number of bacteria.
- Spermatozoa.
Structure:
- Cilium (plural: cilia) is a short, fine strand of hair, about 10μm long and 200nm in diameter.
- Flagellum (plural: flagella) is a long and fine strand of hair. Length: 10-150μm; Diameter: ~200nm.
- Cilia and flagella contain nine pairs of microtubules that are arranged in a ring around two central microtubules. Thus cilia and flagella are said to have a ‘9+2’ microtubule arrangement.
- Radial spokes connect the microtubule pair at the center to the peripheral microtubules.
- Each peripheral pair of microtubule has a pair of dinein arms.
- At the base of cilium and flagellum is the basal body. Basal body has a structure similar to the centriole. Basal body has a ‘9+0’ microtubule arrangement.
- On the outside of cilia and flagella is the plasma membrane.
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| Cilia and flagella structure |
Functions:
- Cilia and flagella are for locomotion by protozoa.
- Cilia in the oviductus help to move ovum down the tube.
- Cilia on the lining of respiratory tracts trap particles.
Diagrams and explanations are fabulous
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