Cilia and flagella, Biology

Assignment Help:

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.

Related Discussions:- Cilia and flagella

Races of modern man, RACE S OF MODERN MAN Australoids Negroids ...

RACE S OF MODERN MAN Australoids Negroids Caucasoids Monogoloids American Indian Polynesian All human races have the same number of chromosomes (46) and b

Regulation of glycogenesis, Regulation  of Glycogenesis Glycogen syntha...

Regulation  of Glycogenesis Glycogen synthase,  the key enzyme in glycogenesis, is activated by insulin and glucose and inhibited by CAMP.

Is protein collagen has a high proportion of glycine, The protein collagen ...

The protein collagen has a high proportion (20% or more) of A. asparagine and glutamine B. proline and hydroxyproline C. glycine D. both A and B E. both A and C F

Signs and symptoms of hypoglycaemia, Q. Signs and Symptoms of Hypoglycaemia...

Q. Signs and Symptoms of Hypoglycaemia? Let us now learn about signs and symptoms of hypoglycaemia. It is important for you know these because you can help the patient and fami

Marine ecosystems, Marine Ecosystems Marine ecosystems cover 70 per c...

Marine Ecosystems Marine ecosystems cover 70 per cent of the earth's surface and have an average depth of 3.750 m (the greatest known depth being 10,750 metres in the Mariana

Explain the turbidity measurement, Explain the Turbidity Measurement? P...

Explain the Turbidity Measurement? Presence of sufficient number of microbes makes the liquid medium turbid. Turbidity also increases with the multiplication of microbes. Estim

Define chlorophyll, Chlorophyll Chlorophyll, the pigment responsible fo...

Chlorophyll Chlorophyll, the pigment responsible for giving bright green colour to the vegetables, is very unstable and undergoes changes in colour which are often considered t

Explain the advantages and disadvantages of insulin pen, Advantages of Insu...

Advantages of Insulin Pen - More convenient and easier to transport than traditional vial and syringe. - More accurate doses. - Easier to use for those with visual or fin

Structure of human testis, Structure of human testis: The male repro...

Structure of human testis: The male reproductive system consists of a pair of testis. Testis are male reproductive organs and produce (male gametes) sperms and also secrete

Define the structure of hemicellulose, Structure of Hemicellulose When ...

Structure of Hemicellulose When compared with cellulose, it has lower degree of polymerization, more readily soluble in acid and alkali and non-fibrous. On hydrolysis, it predo

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd