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

Structure and function of lipoproteins, Triacylglycerols, cholesterol and p...

Triacylglycerols, cholesterol and phospholipids are associatively insoluble in aqueous solution. Thus, they are transported around the body in the blood as parts of lipoproteins.

When manifested in homozygosity in the offspring?, Why can it be said that ...

Why can it be said that a recessive allele can remain hidden in the phenotype of an individual and revealed only when manifested in homozygosity in the offspring? A recessive a

Drug management for gout disease, Q. Drug Management for gout disease? ...

Q. Drug Management for gout disease? Drugs are so effective in lowering the serum mate concentration that rigid restriction of dietary purines is rarely necessary. Uricosurie d

Does thermal inversion occur in the winter or in the summer, Q. Does therma...

Q. Does thermal inversion occur in the winter or in the summer? The Pollutant low altitude thermal inversion take place in the winter and in this period of the year the sun hea

What is the inactivation of the x chromosome?what is a barr, What is the in...

What is the inactivation of the X chromosome? What is a Barr body? The Inactivation of the X chromosome is a phenomenon that occurs in women. Ever since women have two X chromo

Lead to protein denaturation, Q. What are some factors that can lead to pro...

Q. What are some factors that can lead to protein denaturation? Protein denaturation can be caused by temperature variation, pH change, changes in the concentration of surround

Explain about the effect of nutrient and drug interaction, Explain about th...

Explain about the Effect of Nutrient and Drug Interaction? Medicines can treat and cure many health problems. Nevertheless, do you recall your doctor advising or recommending c

Sex-limited traits, can u show the different activities on the topic

can u show the different activities on the topic

Components of ecosystem, Components of Ecosystem The components of the ...

Components of Ecosystem The components of the ecosystem can be categorised into abiotic or non-living and biotic or living components; Abiotic components: The important ab

Describe what are non degradable pollutants, Question : (a) Briefly de...

Question : (a) Briefly describe what are non degradable pollutants? (b) What do you meant by ichthyosarcotoxic fishes and give two examples of ichthyosarcotoxic fish poiso

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