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

Chromosomal type-genetic basis of sex determination, Chromosomal Type-Genet...

Chromosomal Type-Genetic basis of Sex Determination It refers to the condition where the genes involvcd in sex dcterrnincltion arc located on specific chromosomes known as the se

Kreb''s cycle, Kreb's cycle is the biochemical cycle in the cellular aerob...

Kreb's cycle is the biochemical cycle in the cellular aerobic metabolism where the acetyl CoA is combined with the oxaloacetate to form citric acid; the resulting citric acid is c

What is carbohydrates, What is Carbohydrates? Carbohydrates : Carbohyd...

What is Carbohydrates? Carbohydrates : Carbohydrates function mainly as immediate sources of energy, stored energy such as starch, and structural components of cells. Carbohyd

Chemical energy of matter, Chemical energy of matter : As is obvious from ...

Chemical energy of matter : As is obvious from  the above  account  living cells  obtain  energy  by breaking   C-C and C-H bonds  of organic  matter under the  process of catabol

Explain the process of nucleotide catabolism, Question 1 Write a short not...

Question 1 Write a short note on the following Free Energy Cori cycle Fermentation Pentose phosphate pathway Transamination Allosteric Regulation Qu

What are the parasympathetic neurons, What are the parasympathetic neurons ...

What are the parasympathetic neurons Patient A has a disease that has destroyed half of the alpha-adrenergic receptors on each of the smooth muscles that control the diameter o

Chemical properties of fatty acids, Chemical Properties of Fatty Acids ...

Chemical Properties of Fatty Acids Esterification Like any other organic acid,  fatty acids also form esters with  various alcohols. An alcohol such as glycerol is reacted

What are the illustrations of the civil law, What are the illustrations of ...

What are the illustrations of the civil law? Illustrations of the civil law: Illustrations of civil actions are defamation of breach, character of contract, trespassing or

Protein case study, DK is a year old female who was born after a normal pre...

DK is a year old female who was born after a normal pregnancy and delivery.  At 17 months of age DK showed signs of speech delay, increased lethargy and vomiting up to four times p

Define the term - lateralisation and localisation, Define the term - latera...

Define the term - lateralisation and localisation Discriminative validity studies including lateralisation and localisation achieved satisfactory results, but the localisation

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