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

Explain major limiting factors of photosynthesis, Q. What are the three maj...

Q. What are the three major limiting factors of photosynthesis? The three major limiting factors of photosynthesis process are light intensity, carbon dioxide temperature and c

Tanco beans, what is the origin, uses, morphology, active constituents and ...

what is the origin, uses, morphology, active constituents and market perparations ?

Compare between isp and soy flour, Compare between ISP and soy flour Th...

Compare between ISP and soy flour The cost of isolated soybean proteins is five to seven times higher than that of defatted soy flour. On an equivalent protein weight basis, th

Cytology, who is the first person who saw the cell

who is the first person who saw the cell

Determine the toe motor neuron that excites a toe muscle, Which of the foll...

Which of the following is true for a toe motor neuron that excites a toe muscle that moves the big toe in the right foot? A. The cell body of the toe motor neuron is located in

Explain what is correction of hypovolemia, Explain what is Correction of Hy...

Explain what is Correction of Hypovolemia ? Intravenous fluids should be given to correct hypovolemia and optimize preload to the heart. This is particularly important in sept

Evaluation of the programme or agency, Evaluation of the programme or agenc...

Evaluation of the programme or agency: It can be  based on following:  i)   Audit or review of programme or agency: This can be continuously done by the staff through in

Poultry and duck diseases-avian encephalomyelitis, Avian encephalomyelitis ...

Avian encephalomyelitis This is an acute infectious disease of birds (3 weeks old), which is caused by a member of the genus Enterovirus in the family Picornaviridae. Epid

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