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

What is the difference between rna and dna, Q. Concerning the nitrogen- con...

Q. Concerning the nitrogen- containing bases that participate in nucleotides, what is the difference between RNA and DNA? In DNA nucleotides can be formed of thymine (T), adeni

Feline leukemia, Feline leukemia The disease is caused by a retrovirus and...

Feline leukemia The disease is caused by a retrovirus and is the most common naturally occurring lymphosarcoma and accounts for nearly 30% of feline tumors. Based on the location

Neurological disorders due to imbalanced nutritional intake, Define Neurolo...

Define Neurological disorders arising due to imbalanced nutritional intake (deficiency or excess)? Common examples are the neurological manifestations  of beriberi, pellagra, p

Show major complications of hypertension, Q. Show Major complications of hy...

Q. Show Major complications of hypertension? High blood pressure is one of the leading causes of kidney failure, also commonly called end-stage renal disease (ESRD).  Major

Biotic potential of a bacterial population, Q. How different is the growth ...

Q. How different is the growth according to the biotic potential of a viral population from the growth according to the biotic potential of a bacterial population? The growth c

How are the female gametes of gymnosperms formed, Q. How are the female gam...

Q. How are the female gametes of gymnosperms formed? What is the relationship between this process and the concept of alternation of generations? In the female strobiles (cones

What is dry mass, What is dry mass? When biomasses are compared often t...

What is dry mass? When biomasses are compared often the method of dry mass is used. The dry mass is the total mass less the water mass of an individual. The total mass is also

The importance of buffer systems in the human body, Outline the importance ...

Outline the importance of buffer systems in the human body. In addition, describe the main biological buffer systems and how they function.

Percussion - criteria for endosteal implants, Percussion - criteria for end...

Percussion - criteria for endosteal implants? It is neither an indicator of clinical health nor of rigid fixation. Ringing sound that occurs on percussion corresponds to the pr

Cellular respiration, Cellular respiration is the transfer of energy from ...

Cellular respiration is the transfer of energy from various molecules to produce ATP; takes place in the mitochondria of the eukaryotes, the cytoplasm of prokaryotes. In the proce

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