Centrioles, Biology

Assignment Help:

Centrioles

  • Centrioles is also called cell centre.
  • Centrosome discovered by Benden. T. Boveri called it centrosome.
  • Centrosome is present in all animal eukaryotic cells but absent in higher plants.
  • H. Fol discovered spindle fibres.
  • Two centrioles located just outside nucleus, lie at right angle to each other.
  • Surrounding cytoplasm is clear called "Centrosphere" or "Kinoplasm".
  • Centrioles + centrosphere = Centrosome or Microcentrum or Diplosome.
  • Due to clear and shining centrosphere, centrioles are previously thought as light artifact. One end of centriole is open and other end is closed.
  • Centrioles are membraneless elongated structure.
  • Centrioles exhibit "Cart Wheel Structure" (Just like Basal body of Cilia). Basal body is also a type of centriole.

 

1208_centrioles.png

  • Each centriole consists of 9 peripheral microtubules and each microtubule made up of three sub tubules which are called A, B and C. So centriole is made up of peripheral triplet.
  • Each subtubule is made up of 13 protofilaments.
  • Each protofilament is a dimer of a and b tubulin protein.
  • Microtubules of centriole are made up of tubulin protein.
  • Central microtubules are completely absent in centriole but in central part Hub protein is present.
  • Each peripheral microtubule connects with hub protein with the help of radial spoke.
  • Terminal end of radial spoke (towards peripheri) forms a dense structure called X-body, which is present near the A-subtubule.
  • Between two X bodies, a Y-body is also present.
  • Each Y-body connected to X-bodies on its both sides.
  • A-C linker connects C- sub tubule of a microtubules with A-subtubule of another microtubule.
  • Randell and Disprey discovered DNA in centriole, which is called centriolar DNA. It has not been isolated till now but its presence is confirmed. Centriolar DNA is probably circular, naked and double stranded. Centriolar DNA helps in duplication of centriole during G phase of cell division but recently it is beleived that Massules or Pericentriolar Satellites help in duplication of centriole.
  • Around each peripheral microtubule a spherical structure is present, which is called Pericentriolar Satellites or Massules. These are 9 in number.
  • Centrioles are self duplicating units, contain DNA and RNA and are capable of protein synthesis.

Related Discussions:- Centrioles

Define future projections in the field of public nutrition, Define Future P...

Define Future Projections in the Field of Public Nutrition? We discussed earlier that the field of public nutrition has existed for a long time, although not by this name. A he

How pregnancy and lactation affects the bmr, How Pregnancy and Lactation af...

How Pregnancy and Lactation affects the bmr? These periods of physiological stress also has an impact on the metabolic rate. Earlier, we studied that REE is highest during the

What the enzymes do to reaction, What do enzymes do to a reaction? Indicate...

What do enzymes do to a reaction? Indicate all that are correct. a. Lower the activation energy b. Reverse the equilibrium c. Lower the equilibrium d. Increase the reac

Explain the determination and application of vitamin e, Explain the Determi...

Explain the Determination of Vitamin E DL-α-Tocopherol is oxidized with ferric chloride and the ferrous ions formed are measured colorimetrially with the aid of α,α'-dipyridyl

Determine the light-near dissociation test, Determine the Light-Near Dissoc...

Determine the Light-Near Dissociation Test The near  response should be  tested  in  a well  lit room  so that  the object  is clearly visible. The patient  is given  an  accom

Amazonian butterflies, The Amazon rainforest in South America is a biodiver...

The Amazon rainforest in South America is a biodiverse ecosystem. There are large numbers of plant and animal species making up the food web, including over 350 species of predator

Explain iron balance and regulation of iron absorption, Explain Iron Balanc...

Explain Iron Balance and Regulation of Iron Absorption? The body has three unique mechanisms for maintaining iron balance. The first is the continuous reutilization of iron fro

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

Describe cultural characteristics of microorganisms, Q. Describe Cultural C...

Q. Describe Cultural Characteristics of Microorganisms? Bacterial growth in and on foods often is extensive enough to make the food unattractive in appearance or otherwise obj

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