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

Which are intracellular organelles present in bacteria, Q. Which are intrac...

Q. Which are intracellular organelles present in bacteria? Considering typical eukaryotic cell organelles heterotrophic bacteria have ribosomes essential for protein synthesis.

Explain citric acid cycle, Explain citric acid cycle In  the citric aci...

Explain citric acid cycle In  the citric acid cycle, the oxaloacetate is first condensed with acetyl CoA, and  then regenerated  as  the cycle  is  comp!eted.  But these  react

Density - population parameters and regulation, Density - Population Parame...

Density - Population Parameters and Regulation Density is defined as number of individuals or population biomass per unit of area or volume at any given time. Biomass refers t

fungi, Fungi The study of fungi (s. fungus) is called mycology. Fungi...

Fungi The study of fungi (s. fungus) is called mycology. Fungi are unicellular or multicellular chemoheterotrophic eukaryotes. They may be grouped into yeasts, molds and funga

Define dissection of the aorta, Q. Define Dissection of the Aorta ? The...

Q. Define Dissection of the Aorta ? The CXR may be abnormal in upto 80 per cent of patients. The abnormalities include: i) Widened mediastinum: This is defined as a mediast

Functions of skin, FUNCTIONS OF SKIN - Skin performs various diverse fu...

FUNCTIONS OF SKIN - Skin performs various diverse functions, that is why it is called "jack of all trades". 1 .      Protection - The skin protects the internal soft or

Where does the water resorbed after glomerular filtration, Q. Where does mo...

Q. Where does most of the water resorbed after glomerular filtration go? What are the other substances resorbed by the nephron tubules? Only 0.5 to 1% of the glomerular filtrat

In the metagenesis of obelia and aurelia, Q. In the metagenesis of Obelia a...

Q. In the metagenesis of Obelia and Aurelia what is the form that produces gametes? What is the form that reproduces asexually? In the metagenesis of some coelenterates, like O

Amphibians, respiratory system in amphibains

respiratory system in amphibains

Of which type of defense cell do worm infections, Of which type of defense ...

Of which type of defense cell do worm infections stimulate the multiplication? The major leukocytes that generally multiply and participate in the defense against worm infectio

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