ROLL NO 21CHBSA132 ENROLLMENT NO GM8072 INDEX HISTORY MORPHOLOGY ORIENTATION STRUCTURE FUNCTION BIOGENESIS DISEASES REFRENCES HISTORY 1850 Kolliker first observed mitochondria as granular structures in striated muscle ID: 1047967
Download Presentation The PPT/PDF document "MITOCHONDRIA NAME – MD. SAMAD" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. MITOCHONDRIANAME – MD. SAMADROLL NO. – 21CHBSA132ENROLLMENT NO. – GM8072
2. INDEXHISTORYMORPHOLOGYORIENTATIONSTRUCTUREFUNCTIONBIOGENESISDISEASESREFRENCES
3. HISTORY1850 -Kolliker first observed mitochondria as granular structures in striated muscle.1882 - Flemming demonstrated thread-like bodies in many cells and called them filia. 1892 - Altmann referred to the mitochondria as bioplasts, and introduced the bioplast theory according to which the bioplasts were considered to be symbionts comparable to bacteria. 1898 - Benda developed the crystal violet staining technique and called the structures mitochondria. 1900 - Michaelis used the dye Janus green B as a vital stain. 1912 - Kingsbury suggested that mitochondria were the sites of cellular respiration.1940s and 1950s - Palade and Sjostrand worked out the fine structure of the mitochondria under the electron microscope.1944 - Claude separated the mitochondrial fraction from other cell components by ultracentrifugation.
4. MORPHOLOGY SIZE : The average length of the mitochondria is 3-4 microns and average diameter 0.5 to 1.0 microns. In muscles most of the mitochondria are 2-3 microns long, but bodies 8-10 microns long have also been found.DISTRIBUTION : Ordinarily mitochondria are evenly distributed in the cytoplasm. They may, however, be localized in certain regions, In the proximal convoluted tubules of the kidney they are found in the basal region of the cell, opposite the renal capillaries. In skeletal muscles they lie between the myofibrils. In insect flight muscle several large mitochondria are in contact with each fibril. cardiac muscle the mitochondria are situated in clefts between the myofibrils. Numerous lipid droplets are associated with the mitochondria. In many sperms the mitochondria fuse into one or two structures which lie in the middle piece of the tail, surrounding the axial filament. In columnar or prismatic cells they are oriented parallel to the long axis of the cell. In leucocytes they are radially arranged.
5. 3. SHAPE : Mitochondria vary in shape but are generally granular or filamentous. If a filamentous mitochondria swells at one end it gives a club-shaped appearance. If the swollen end hollows out then the appearance is that of a tennis racket. Pleomorphic forms may contain swellings at both ends. If there is a central clear zone the mitochondrion becomes vesicular.4. NUMBER : The number of mitochondria varies in different cell types. Cells with high metabolic activity have a high number of mitochondria, while those with low metabolic activity have low number. In a normal liver cell there are 1000-1600 mitochondria. Large sea urchin eggs have 13,000-14,000, while in some oocytes there are about 3,00,000. In protozoan Chaos chaos there are about 5,00,000 mitochondria.
6. ORIENTATIONThe mitochondria have definite orientation. For example, in cylindrical cells the mitochondria usually remain orientated in basal apical direction and lie parallel to the main axis. In leucocytes, the mitochondria remain arranged radially with respect to the centrioles. As they move about in the mitochondria form long moving filaments or chains, while in others they remain fixed in one position where they provide ATP directly to a site of high ATP utilization, e.g., they are packed between adjacent myofibrils in a cardiac muscle cell or wrapped tightly around the flagellum of sperm.
7. STRUCTUREA mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins. The two membranes have different properties. Because of this double-membrane organization, there are five distinct parts to a mitochondrion. They are:OUTER MEMBRANEINNER MEMBRANEINTERMEMBRANE SPACECRISTAEMITOCHONDRIAL MATRIX
8. OUTER MEMBRANESimple phospholipid bilayer.It encloses the mitochondrion.Containing protein structures called porins.lons, nutrient molecules, ATP, ADP, etc. can pass through the outer membrane with ease.
9. INNER MEMBRANEIs 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.
10. INTERMEMBRANE SPACEThe space between inner membrane and outer membrane (O cavity}It has high proton concentration.The space between inner and outer memebrane is approximately 70 angstrom.Concentration is same as that of the cytosol.
11. CRISTAEAre folds of inner mitochondrial membrane.Stalked particles or inner membrane spheres: cristae is covered with this inner membrane spheres caked stalked particles or knobs or heads.They contain protein called F1 portion & FO portion. For ATP synthesis and ATO oxidation
12. MITOCHONDRIAL MATRIXGel like consistencyDense ,homogenous2/3rd of total protein of mitochondriaMitochondria have:- EnzymesRibosomeDNAmRNAGranulesFibrilsTubules.Major enzymes include enzymes involved in:- Synthesis of nucleic acid and proteinsFatty acid oxidation TCA CYCLE (except succinate dehydrogenase)
13. FUNCTIONSMitochondria are the powerhouses of the cell. They supply nearly all the required biological energy. Only the mitochondria are fully capable of converting pyruvic acid to carbon dioxide and water.
14. CELL RESPIRATIONMitochondria are the respiratory centres of the cell. Cell respiration can be divided into four phases: (1) glycolysis, (2) oxidation of pyruvic acid, (3) Krebs citric acid cycle and (4) oxidative phosphorylation through the hydrogen/electron transport system.Glycolysis: involves the breakdown of glucose to pyruvic acid. The enzymes for glycolysis are found in the cytosol, outside the mitochondrion.
15. 2) Oxidation of pyruvic acid: Pyruvic acid is degraded to acetyl CoA, with the liberation of a pair to hydrogens (2H).
16. 3) Krebs citric acid cycle: Acetyl CoA condenses with oxalo-acetic acid to form citrc acid. After several steps oxaloacetic acid is generated. Four dehydrogenation reactions take place during the cycle, in each of which a pair of hydrogens (2H) is liberated. One ATP molecule is formed at substrate level during Krebs cycle. The enzymes for Krebs cycle are found in the matrix of the mitochondrion.
17. 4) Oxidative phosphorylation: It has been seen that pairs of hydrogen (2H) are liberated during aerobic glycolysis, oxidation of pyruvic acid and the Krebs cycle. These hydrogen pairs are passed down the hydrogen/electron transport chain (respiratory chain), and oxidative phosphorylation takes place. Three molecules of ATP (two when succinate is the acceptor) are generated per pair of electrons passing down the electron transport chain. The enzymes for electron transport are located in the inner membrane of mitochondrion. The transfer of hydrogens/electrons takes place through a complex chain of hydrogen donors-acceptors consisting of flavoproteins, coenzyme Q and cyto chromes. The respiratory chain is arranged in five complexes (I to V). Oxygen is the final hydrogen acceptor.
18. ATP TRANSPORTThe ATP molecules produced as a result of cellular respiration accumulate in the mitochondria. The mitochondria collect at sites where energy requirement is high. As a result of membrane contraction, and increase in internal hydrostatic pressure of the mitochondrion, water and ATP are squeezed out. This results in a lowering of the ATP concentration, and the mitochondrial membrane relax. The thyroid hormone thyroxin causes the mitochondria to swell, while ATP brings about contraction.
19. LIPID SYNTHESISA set of enzymes that control synthesis of lecithin and phosphatidyl ethanolamine from fatty acids, glycerol and nitrogenous bases is present in most mitochondria.
20. ELONGATION OF FATTYY ACIDSMammalian mitochondria have a group of enzymes that carry out elongation of fatty acids by adding acetyl-CoA, and subsequently reducing the keto acid produced. By this method myristate is elongated topalmitate; palmitate to stearate, etc.
21. MITOCHONDRIAL BIOGENESISMitochondrial biogenesis is the cellular process that produces new mitochondria. But mitochondria cannot be produced from scratch (de novo); new mitochondria are produced by adding new content—proteins, membranes—to pre-existing mitochondria.Mitochondrial biogenesis can be upregulated as part of a concerted adaptive cellular response to metabolic challenges. This response increases ATP output and manages ATP expenditure in times of need. The increase in mitochondrial mass resulting from mitochondrial biogenesis is accompanied by an increase in the mitochondrial machinery for fatty acid oxidation, the citric acid cycle, and oxidative phosphorylation, enhancing the cell’s capacity to produce ATP from food.
22. DISEASESEncephalopathy-strokes, seizures, regressionBlindnessHormone deficienciesLiver failure EnteropathyMyopathyDeafnessCardiomyopathyDiabetesRenal diseaseAnaemiaNeuropathy
23. REFRENCESWikipediaBooks :-Cell biology by Smith and WoodCell Biology,Genetics,Molecular Biology by P.S.VermaThe Cell A Molecular Approach by Geoffrey M. CooperMolecular Cell Biology by LodishCell and Molecular Biology by Gerald Karp
24. THANK YOU