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

State in brief about respiration, State in brief about respiration When...

State in brief about respiration When we breathe in the air, our chest expands and air is taken in the lungs and when we breathe out chest returns to its resting position. This

Excretory system, what is the excretory system of a crab?

what is the excretory system of a crab?

Orifices of heart, Atrio-ventricular Orifices The right and left atrio-v...

Atrio-ventricular Orifices The right and left atrio-ventricular orifices are oval apertures. The openings lie in a plane that is almost vertical with a slight downward inclinati

Explain adverse effects of ketoconazole, Explain Adverse Effects of ketocon...

Explain Adverse Effects of ketoconazole Anorexia, nausea and vomiting are common with higher doses (>400 mg/day) of ketoconazole; taking the drug with food or at bedtime may i

What is acetobacter, Q. What is Acetobacter? These bacteria, also known...

Q. What is Acetobacter? These bacteria, also known as "vinegar bacteria", cause significant spoilage in the wine industry but are necessary for vinegar production. The importan

Mechanism of enzyme action, Mechanism  of Enzyme Action  The action of...

Mechanism  of Enzyme Action  The action of enzymes is to lower  the activation energy  or threshold  of their substrates which. Therefore  become  activated and   react  with

Medical therapy for aortic stenosis, Q. Medical Therapy for aortic stenosis...

Q. Medical Therapy for aortic stenosis? Definitive therapy for aortic stenosis is surgical and medical therapy is only palliative. Infective endocarditis and rheumatic fever p

Explain phylum zygomycetes, Phylum Zygomycetes 1) Asexual reproduction ...

Phylum Zygomycetes 1) Asexual reproduction by non-motile spores produced from a stalked spore case which is known as sporangium. 2) They reproduced by- conjugation between n

Brief descriptions of how to test, If sugar is heavier than aspartame, then...

If sugar is heavier than aspartame, then the can of regular soda will sink. How will you test this hypothesis? Write brief descriptions of how you could test?

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