Cell mitochondria ppt

Structure of Mitochondria

1. M itochondria Angel Anna Lal Msc Biotechnology 1 st year.

2. INTRODUCTION The  mitochondrion  (plural  mitochondria ) .[ greek ]; It is a double membrane-bound organelle found eukaryotic cells. mito= thread chondrion = granule like Found in cytoplasm of the cell. Power house of cell. First observed by Richard Altman (1894). Term mitochondria was coined by Carl Benda (1898).

3. MORPHOLOGY SIZE: Mitochondria range from 0.5 to 1.0  μm  in diameter. SHAPE: normally Sausage shaped, In fibroblasts -elongated and thread like NUMBER : Depends on type size and functional state of cell. Eg : An average liver cells contain around 1500 mitochondria . LOCATION : Cells with high enrgy requirements; Eg:Sperm tail, Muscle, Flagella

4. CTOPLASMIC INHERITANCE In most animals , oozyte mitochondria [maternal ] are the only mitochondria that is inherited . Spermatazoa mitochondria [paternal] also enters oocyte during fetilization,but destroyed during early embryonic development. Mechanism not yet ellucidated .

5. STRUCTURE Outer Membrane Intermembrane Space Inner Membrane Cristae Matrix

6. OUTER MEMBRANE Simple phospholipid bilayer. It encloses the mitochondrion. Containing protein structures called porins. Ions, nutrient molecules, ATP, ADP, etc. can pass through the outer membrane with ease. INNER MEMBRANE Is freely permeable only to oxygen, carbon dioxide, and water. Contains complexes of the ETC, the ATP synthase complex, and transport proteins. Presence of sophisticated ion transporters exist. Several antiport systems exist, allowing exchange of anions between the cytosol and the mitochondrial matrix. It is devoid of cholesterol and rich in phospholipid & cardiolipin.

7. Intermembrane space Matrix

8. Intermembrane space the space between inner membrane and outer membrane {O cavity} It has high proton concentration. The space between inner and outer memebrane is approx 70 angstrom. Conc is same as that of the cytosol . CRISTAE Are folds of inner mitochondrial membrane. Stalked particles or inner membrane spheres : cristae is covered with this inner membrane spheres called stalked particles or knobs or heads. They contain protein called F1 portion & F0 portion. For ATP synthesis and ATO oxidation.

9. MITOCHONDRIAL MATRIX: Gel like consistency Dense ,homogenous 2/3 rd of total protein of mitochondria Mitochondria have: - enzymes -ribosomes -DNA -mRNA -granules -fibrils -tubules. Major enzymes include enzymes involved in: -Synthesis of nucleic acid and proteins -Fatty acid oxidation -TCA CYCLE ( except succinate dehydrogenase )

10. MITOCHONDRIAL DNA (mt DNA ): Double stranded, covalently closed, circular molecule. Occurs in multiple copies. Most usually remains attached to inner mitochondrial membrane. Stores biological info required for growth and multiplication of mitochondria. Can undergo replication and duplication. Human mt DNA 2 rRNA 22 tRNA Not absolutely autonomous depends on nuclear DNA .[partially autonomous]

11. FUNCTIONS OF MITOCHONDRIA: Energy transducer of the cell- synthesis of ATP Kreb’s cycle in matrix ETC system Phosphorylating system- ATPase Extra mitochondrial inheritance: mtDNA contains plasma genes (extra chromosomal genes) Transmitted from mother to the offspring Synthesis of mtDNA, RNA, protein. Bring about gene expression through gene duplication transcription and translation. Synthesis 13 different polypeptides in human.

12. Site of several metabolic reactions Outer membrane Oxidation of epinephrine Degradation of tryptophan Elongation of fattyacid Inner membrane : oxidative phosphorylation Matrix Kreb’s cycle Beta oxidation Detoxification of ammonia in urea cycle Storage of calcium ions

13. Other functions: production of heat ( non shivering thermogenesis). [ The unharnessed potential energy of proton-electrochemical gradient produced during ETC is released as heat .] Role in apoptosis ( programmed cell death). Synthesis of estrogen and testosterone. Role in neurotransmitter metabolism. Role on cholesterol metabolism.