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

Describe some food borne diseases, Q. Describe some Food borne disease? ...

Q. Describe some Food borne disease? Food borne diseases are caused by the ingestion of foods containing toxic or infectious agents. In India, the diseases transmitted by foo

Why enzymes work to speed up a chemical reaction, Enzymes work to speed up ...

Enzymes work to speed up a chemical reaction by: a. attaching coenzymes to the substrate b. heating up the substrate c. lowering the activation energy of the reaction d. supplyi

Define the meaning of isomerism, Define the Meaning of Isomerism? All m...

Define the Meaning of Isomerism? All monosaccharides exhibit isomerism. An asymmetric carbon or chiral carbon contains four different groups attached to it. The formula 2 n de

What is the concept of lophophore, What is the concept of Lophophore? A...

What is the concept of Lophophore? A unique double ring of hollow ciliated tentacles that surround the oral opening in some animal phyla. There is some debate as to whether the

Monitoring of risk management, Monitoring of risk management Assessment...

Monitoring of risk management Assessment of effectiveness  of measures taken, and review risk  management  and/or assessment,  as  necessary. The outcome of the risk evaluation

Why is a balanced frequency of different alleles of a gene, Why is a balanc...

Why is a balanced frequency of different alleles of a gene in a population more useful for the survival of that population facing environmental changes? For the trait condition

Lipids, Lipids All animal tissues contain lipids or fats as essential...

Lipids All animal tissues contain lipids or fats as essential components of cell membrane. It is also stored in certain tissues. Lipids are body's chief source of energy and

What is catharanthus roseus pharmaceutical compounds, Q. What is Catharanth...

Q. What is Catharanthus roseus pharmaceutical compounds? This species yielded the alkaloids vincristine and vinblastine. Traditionally used by various cultures for the treatmen

Define prevalence of weight management, Define Prevalence of Weight Managem...

Define Prevalence of Weight Management? WHO (1998) estimates that in developing countries about 245 million adults are moderately underweight and 93 million severely underweigh

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