Structure of mitochondria, Biology

Assignment Help:

STRUCTURE

Mitochondria is a double unit membranous structure. It consists of outer & inner membranes.


2143_mitochondria.png

  • Outer membrane is smooth & made up of lipoproteins. It bears many non stalked particles. These particles are known as subunits of parson. In outer membrane carrier protein is also present. Carrier protein is similar to bacterial porins (proteins), which is present in gram negative bacteria.
  • Outer membrane has more phospholipids (Phosphatidyl choline) and cholesterol as compared to inner membrane.
  • Inner membrane is selectively permeable in comparison to outer membrane. Many types of enzymes are present in inner membrane, which are involved in ATP synthesis (oxidative phosphorylation). Outer surface of inner membrane is called C- face while inner surface called M- face. Inner membrane is folded into a number of finger like cristae. Cristae are tubular finger like but in fungi cristae' are plate like while in Euglena cristae are vesicle shaped. Cristae word coined by Palade. Inner membrane have electron acceptors arranged in a definite sequence and form electron transport system (ETS). Inner membrane is studded with pin head particles called oxysomes or elementary particles or particles or subunits of Fernandez Moran. (104  to 106 in number). Each F particle consists of three parts - Basal plate, Stalk and Head. ATP synthesis occur in head region of oxysome because here ATPase enzyme is present. Synthesis of ATP in head region can be proved by sonication experiment. There is a factor at the base of oxysome that is called F which attach particles to inner mitochondrial membrane. This factor also termed as Oligomycin Sensitivity Conferring Protein (OSCP) Oxysomes composed of ATPase enzymes and concerned with Oxidative phosphorylation (Recker 1967).

596_mitochondria1.png

  • Unit of mitochondria = Oxysomes.
  • Unit of ATP synthesis = Oxysomes
  • Inner membrane have less phospholipids. Phospholipid in inner membrane is mainly diphosphatidyl glycerole.
  • Each membrane has thickness of 60-75 Å Both membrane separated by a outer chamber or perimitochondrial space (80-100Å). This space is rich in coenzymes and enzymes required for oxidation of fats.
  • Inner chamber enclosed by inner membrane which consists of matrix. Mitrochondrial matrix have 70% of total cell enzymes, which are involved in Kreb's cycle. Beside these enzymes matrix have a complete protein synthesis apparatus. Matrix contains mtDNA, RNA and ribosomes.

mtDNA is circular or double stranded. It has :-

1. High G-C content

2. High melting point

3. High renaturation temperature

4. It can replicate itself during any stage of cell division (from G-2 to cytokinesis)

5. 2-6 copies present in each mitochondria.

6. Mitochondrial DNA can code the synthesis of 10 different types of proteins ( Membrane proteins). Rest of the proteins and enzymes of mitochondria are synthesized under the control of nuclear genes.

7. Mitochondrial DNA was discovered by Nash and Margit (1963).

8. Enzymes for replication and transcription of DNA like DNA- polymerase and RNA polymerase.

  • In mitochondria 70s types ribosomes are present, which are known as mitoribosomes. (Mitochondria of mammals have 55s ribosomes)
  • In scurvy disease several mitochondria fuse to form large bodies called chondriosphere.

Related Discussions:- Structure of mitochondria

Nursing assessment of acute glomerulonephritis, Nursing Assessment   Du...

Nursing Assessment   During assessment the child's parents will give you history of upper respiratory infection or skin infection  in the previous one to three weeks. Initially

Immediate post-operative care to a cardiac patient, Immediate Post-operativ...

Immediate Post-operative Care The patient is accompanied to the ICU by a surgeon, anesthetist and the nurse who assisted for the surgery with portable ventilator and ECG

Source of cells for regeneration, Source of Cells for Regeneration It...

Source of Cells for Regeneration It had been considered earlier that interstitial cells constitute a reserve of undifferentiated cells that provide the cellular material for

Define the advatages of potassium, Define the advatages of Potassium Th...

Define the advatages of Potassium The gross impact of these effects on crop production is manifested  in several ways. Perhaps the first visible indication of a potassium defic

Digestion, Adsk question #Minimum 100 words accepted#saliva enzyme

Adsk question #Minimum 100 words accepted#saliva enzyme

Illustrate dilated cardiomyopathy, Q. Illustrate Dilated cardiomyopathy? ...

Q. Illustrate Dilated cardiomyopathy? It is a disease of unknown etiology, affecting myocardium. Its diagnosis is established by presence of left ventricular dilatation and sys

What are the advantages of mucoperiosteal flap, Advantages of mucoperiostea...

Advantages of mucoperiosteal flap There is no tissue loss It is advantageous in cases where there is deficiency of keratinized tissue and the soft tissue is not lost, but ma

Excretory organ and waste product, name the excretory ogran and waste produ...

name the excretory ogran and waste product formed in various types of animals

Impediments to infuse biology - lack of trained people, Define Impediments ...

Define Impediments to infuse biology - Lack of trained people? At present, biologists as a rule have not been trained sufficiently in quantitative approaches. A heavy dose of m

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