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

Why is the cytoplasm of sperm cells very reduced, Why is the cytoplasm of s...

Why is the cytoplasm of sperm cells very reduced? Why do mitochondria of sperm cells concentrate in the base of the flagellum ? The decreased cytoplasm of sperm cells reduces th

Pathophysiology of tricuspid regurgitation, Q. Pathophysiology of Tricuspid...

Q. Pathophysiology of Tricuspid regurgitation? Tricuspid regurgitation is associated with prominent venous filling waves and elevated right atrial venous pressures. Hepatic and

Simple or unilayered epithelia, SIMPL E EPITHELIA (UNILAYERED EPITHELIA) -...

SIMPL E EPITHELIA (UNILAYERED EPITHELIA) - 1 .      SIMPLE SQUAMOUS EPITHELIUM (PAVEMENT EPITHELIUM) - It is composed of large flat cells whose edges fit closely toge

Describe circulatory system, Circulatory system:  One of the eleven major b...

Circulatory system:  One of the eleven major body organ systems in animals; carbon dioxide, nutrients, transports oxygen, and waste products between the cells and the respiratory s

Define precautions for preparation of phosphate buffers, Define Precautions...

Define Precautions for Preparation of Phosphate Buffers? 1. Glass electrodes should always be dried before and after measuring pH with a tissue paper. 2. The pipettes should

Gametes and genotypes, what type of gametes would be produced from genotype...

what type of gametes would be produced from genotype AA, Bb, AABb and someone who is heterozygous for 3 traits

Characteristic features of avian gastrulation, Characteristic Features of A...

Characteristic Features of Avian Gastrulation Creation of hypoblast and its important role in formation of the axis and orientation of embryo. Existence of the cells

Ventilation of tracheal system – passive suction ventilation, Ventilation o...

Ventilation of Tracheal System – Passive Suction Ventilation Many active insects and insects that live in environments where water is scarce cannot depend on diffusion alone t

Which is needed to stimulate the activity, Synthesis of fatty acids require...

Synthesis of fatty acids requires the movement of citrate out of the mitochondria. This occurs under conditions of high levels of acetyl CoA which is needed to stimulate the activi

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