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

What is punnett squares in genetics, What is Punnett Squares in genetics? ...

What is Punnett Squares in genetics? The probability, or likelihood, that a certain phenotypic or genotypic trait will appear in offspring can be predicted and diagrammed using

What is the difference between haploid and diploid, What is the difference ...

What is the difference between haploid and diploid? why are so many anesthesias fat solvents Why is it important for core body temperature to stay more constant than skin tem

Define protein requirements for physical fitness, Define Protein Requiremen...

Define Protein Requirements for physical fitness? Proteins provide energy to the body. Since exercise may increase an athlete's need for protein, depending on the type and freq

Why is ridge mapping required, Why is ridge mapping required and what is it...

Why is ridge mapping required and what is its alternative The selection of the implant diameter apart from the mesiodistal space available also depends on the buccolingual widt

What are the main intraspecific ecological interactions, Q. What are the ma...

Q. What are the main intraspecific ecological interactions? The major harmonious intraspecific ecological interactions are societies and colonies. The major inharmonious intras

Explain the composition of nutrient agar and nutrient broth, Explain the Co...

Explain the Composition of Nutrient Agar and Nutrient Broth? The composition and procedure for preparation of some commonly used media, which we will use in the laboratory for

Alfieri repair-technique of operation, Alfieri Repair: This is advised ...

Alfieri Repair: This is advised for ischaenlic mitral regurgitation. In the area of prolapse, the anterior and posterior leaflet edges are approximated with one or two mattress

How is the structure of a mitochondrion well adapted, How is the structure ...

How is the structure of a mitochondrion well adapted for the activities it carries out? The mitochondrial membranes segregate the enzymes and reactants of the Krebs cycle, faci

phylum , characters of phylum rynchocephali

characters of phylum rynchocephalia

Plasmodesmata, PLASMODESMATA Termed by Tangl & Strasburger. Cytop...

PLASMODESMATA Termed by Tangl & Strasburger. Cytoplasmic / Protoplasmic bridges between 2 adjacent cells. Desmotubules connects the E.R. of 2 cells. Plasmodesmata p

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