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

Aceolomates, what are phylums included in aceolomates?

what are phylums included in aceolomates?

Indicate the probability of producing, I have no idea how to do this: two g...

I have no idea how to do this: two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probability of producing: an AB phe

What are cilia and flagella, What are cilia and flagella? Cilia and fla...

What are cilia and flagella? Cilia and flagella are structures found in prokaryotes as well in eukaryotic cells. They play defense, nutrition and movement roles for the cell. I

What are the implant selection errors, Implant Selection Errors There a...

Implant Selection Errors There are a plethora of commercially available implant systems and designs. Qualitative and quantitative nature of the available bone should be careful

Dermatitis, D i se a se s of Skin Der m a t i t i s De...

D i se a se s of Skin Der m a t i t i s Dermatitis is the inflammation of dermis and epidermis resulting in pain on palpation and erythema. E t iolo

What is ridgemapping, What is Ridgemapping The patient is given local ...

What is Ridgemapping The patient is given local anesthesia by infiltration to numb both the  facial (labial/buccal) and  lingual (palatal) mucosa. Using either a sharp straigh

Zoology, Wheel organ of amphioxus.

Wheel organ of amphioxus.

Cellular specific immune response, Q. What is the difference between cellul...

Q. What is the difference between cellular specific immune response and humoral specific immune response? Humoral specific immune response is the defense system by means of, an

Orbital shaker, How I can optimize shake flask culture?

How I can optimize shake flask culture?

Ecosystem degradation and wildlife, Ecosystem Degradation and Wildlife ...

Ecosystem Degradation and Wildlife Man is an animal with ecological requirements just like any other animal. It constantly needs a source of energy and.minera1 nutrients for i

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