Cilia and flagella, Biology

CILIA AND FLAGELLA

  • Purkinje first observed ciliary movement.
  • Hodge studied detail structure of sperm flagellum.
  • Manton studied structure of cilia in plants.
  • Cilia and flagella are simillar in structure. There are some external differences between cilia and flagella.

Cilia

Flagella

Shorter - 5 to 1 0 m in length

 

More in number on a cell

(14000/cell)

 

Exhibit sweeping or pendular movement.

It includes power stroke and recovery stroke.

Action co-ordinated

upto 150 m long

 

Few in number

(1-8/cell)

 

undulating movement

 

Action not co-ordinated

  • Both structures help in locomotion, excretion, secretion and transportation.
  • Cilia and flagella are present in eukaryotic cells except slime moules.
  • Cilia and flagella are also present in prokaryotic cells except Anabena (BGA).
  • Cilia and flagella shows 9+2 arrangement of microtubules.
  • Cilia and flagella consists of 3 parts -

(1) Basal body                 (2) Basal Plate               (3) Shaft

(1) Basal body

  • It is also known as kinetosome or basal granule or blepheroplast.
  • It has 9+0 orientation of microtubule.
  • Hub protein present in the proximal part of basal body but absent in distal part.
  • Central part of basal granule is composed of semisolid cytoplasm called "Central Hub". Microtubules connected to central Hub with the help of protein fibres called primary fibres. Secondary fibres connect microtubules with each other. The triplet microtubules form an angle of 40° with the tangent of basal granule.
  • Rootlet - A conical bundle of protein fibers arise from basal body, Rootlet have dark bands composed of ATPase.
  • Synthesis of ATP takes place in dark bands.

(2) Basal Plate

  • Present between basal body and shaft.
  • It conects basal body and shaft to each other.
  • Two major changes occur at the region of basal plate -

(i) Triplet of peripheral microtubule convert into doublet of microtubules. (ii) Central microtubules develop from distal end of Hub protein.

(3) Shaft

Shaft consists of two parts -

(i) Sheath

(ii)  Axoneme

  • Outer covering of cilium or flagellum is called sheath. Peripheral sheath covers peripheral microtubule whereas central sheet covers central microtubules.
  • Axoneme of shaft consists of 11 microtubules (9 peripheral and 2 central).

738_cilia and flagella.png

  • Axoneme shows 9+2 arrangement of microtubules.
  • Each peripheral microtubule consists of A and B subtubule.
  • A subtuble has two bent arms, these are made up of dyenine proteins. These arms directed in clockwise fashion. Arms of A-tubules composed of an enzymatic protein. Dynien similar to myosin of muscles. Dynien protein have ability to split A TP ( in presence of Ca+ 2 and Mg+2) and liberate energy for movement. Cilia and flagella bend or move due to sliding of microtubules along one another while maintaining their individual length (mechanism simillar to muscle contraction).
  • Each peripheral microtubules consists of tubulin protein. Tubulin simillar to Actin protein of muscles.
  • A and B subtubules connected to each other with the help of Nexine protein.
  • Both central microtubules connected to each other with protoplasmic bridge. Central sheath is present around the central microtubule.
  • Each A subtubule liked to central sheath with the help of radial spoke. Terminal end of radial spoke forms knob like structure that is known as spoke head. Spoke head is present near to central sheath.
  • Transition junctions are also present between central sheath and spoke head.
  • Shaft of cilium of flagellum filled with proteinacious matrix.
Posted Date: 10/5/2012 8:48:44 AM | Location : United States







Related Discussions:- Cilia and flagella, Assignment Help, Ask Question on Cilia and flagella, Get Answer, Expert's Help, Cilia and flagella Discussions

Write discussion on Cilia and flagella
Your posts are moderated
Related Questions
An increase in the calcium conductance of all sarcoplasmic reticulum membranes of a skeletal muscle with no external forces on it leads to A. Increased binding of calcium ions

Q. Is the interphase of mitosis different from the interphase of meiosis? The interphase mitosis that proceeds is similar to the interphase that precedes meiosis. In them the m

Define Typical Ambient Air Pollutants Particulate matter Sulfur containing compounds Organic compounds Nitrogen containing compounds Carbon monoxide

Q. Explain the taxonomic concepts? The history of classification is an exciting aspect of plant taxonomy. The discovery of the use of plants for food and later as medicine bega

Define the term- brain circuitry underlying addiction By unraveling brain circuitry underlying addiction, scientists have identified new targets for therapies which might quell

Explain the Kingdom Fungi organisms? Kingdom Fungi consists of mostly eukaryotic, multicellular, non-photosynthetic organisms that derive their nutrients by absorption. Fungi

Concerning the number of hosts how are parasites classified? Parasites that need only one host are known as monoxenous parasites. Parasites that need more than one host for th

Minerals :-Copper Food Source      Organ meats, sea foods, nuts, seeds Nutritional Functional role Essential nutrient: Deficiency is rare. Catalyst: Lipid perox

Q. Describe about Collective or Universal consciousness? Neurochemicals and associated brain processes are simply channel selectors for various states of consciousness. All sta

Q. What are the common contraindications of the contraceptive pills? There are medical reports associating the use of contraceptive pills with vomiting, headaches, vertigo, nau