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

How does sexual reproduction occur in bacteria, How does sexual reproductio...

How does sexual reproduction occur in bacteria? How different are the modalities of bacterial sexual reproduction? Sexual reproduction happens when bacteria incorporate genetic

Difference between reproduction system of man and rabbit, Difference betwee...

Difference between Reproduction System of man and rabbit -   S.No.   Man   Rabbit   1.   2.   3.

Lower oesophageal sphincter, Q Lower Oesophageal Sphincter? Competency ...

Q Lower Oesophageal Sphincter? Competency of LES (Lower Oesophageal Sphincter) is important. The pressure of this sphincter is controlled by many factors, one of which is hormo

#title.protozoa classes., #question.give the classes of protozoa phylum in ...

#question.give the classes of protozoa phylum in detail with examples .

Conduction, Conduction An action potential occurs at one point along t...

Conduction An action potential occurs at one point along the axon. Yet we know that neurological impulses are not fixed, they travel along a neuron. So how can the action pote

Why is pattern baldness more common in men than in women, Why is pattern ba...

Why is pattern baldness more common in men than in women? Pattern baldness is handled by the allele B. Testosterone interacts with the heterozygous genotype (BB′) to make baldn

Explain signal hypothesis, A classical secretory protein vary from a cytoso...

A classical secretory protein vary from a cytosolic protein by having a sequence about 13-35 amino acids long at its N-terminal end called as a signal peptide or signal sequence.

Class of mollusca - aplacophora, Class of Mollusca - Aplacophora Worm...

Class of Mollusca - Aplacophora Worm-like, no shell, head or excretory organs mantle with chitinous cuticle or scales or spicules mantle cavity posterior. Aplacophorans are a

Determine in brief about the mse, Determine in brief about the MSE The ...

Determine in brief about the MSE The MSE deals with questions concerning the addressee's Consciousness, Emotional State, Thought Content and Clarity, Memory, Sensory Perception

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