A brief discussion on Mitochondria and Chloroplast


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Mitochondria and Chloroplast are two important organelles of a cell body.

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A brief discussion on Mitochondria and Chloroplast

  1. 1. Introducing with CHLOROPLAST & MITOCHONDRIA A Brief on Mitochondria and Chloroplast
  2. 2. Mitochondrion Mitochondria & Chloroplast
  3. 3. Mitochondrion Definition: The mitochondrion (plural mitochondria) is a membrane- bound organelle found in most eukaryotic cells (the cells that make up plants, animals, fungi, and many other forms of life). Mitochondria range from 0.5 to 1.0 micrometer (μm) in diameter. These structures are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. Mitochondria & Chloroplast
  4. 4. Origin & History  When life first began on our planet, single celled organisms produced energy in a way that was highly inefficient (anaerobic respiration, meaning without oxygen) compared to what most multi-cellular organisms use today (aerobic respiration, using oxygen).  Through evolutionary time, plants came about and were able to produce oxygen in the atmosphere giving rise to aerobic respiration which produced energy in a highly efficient manner. Mitochondria & Chloroplast
  5. 5. Origin & History  The theory of endosymbiosis suggests that mitochondria were once free living organisms on their own that used aerobic respiration. Larger anaerobic cells simply engulfed these aerobic mitochondria to use their energy, giving rise to complex cells we find today such as those in our bodies.  The first observations of intracellular structures that probably represent mitochondria were published in the 1840s. Mitochondria & Chloroplast
  6. 6. Structure  A mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins. The two membranes have different properties. Because of this double-membraned organization, there are five distinct parts to a mitochondrion. Mitochondria & Chloroplast
  7. 7. Structure Five distinct parts to a mitochondrion are:  the outer mitochondrial membrane  the intermembrane space (the space between the outer and inner membranes)  the inner mitochondrial membrane  the cristae space (formed by infoldings of the inner membrane)  the matrix (space within the inner membrane) Mitochondria stripped of their outer membrane are called mitoplasts. Mitochondria & Chloroplast
  8. 8. Organization and distribution  Mitochondria are found in nearly all eukaryotes.  They vary in number and location according to cell type.  A single mitochondrion is often found in unicellular organisms.  Conversely, numerous mitochondria are found in human liver cells, with about 1000–2000 mitochondria per cell, making up 1/5 of the cell volume. Mitochondria & Chloroplast
  9. 9. Function  Energy conversion • Pyruvate and the citric acid cycle • NADH and FADH2: the electron transport chain • Heat production  Storage of calcium ions  Additional functions • Signaling through mitochondrial reactive oxygen species • Regulation of the membrane potential • Calcium signaling • Steroid synthesis. Mitochondria & Chloroplast
  10. 10. Genome  The human mitochondrial genome is a circular DNA molecule of about 16 kilobases.  It encodes 37 genes: 13 for subunits of respiratory complexes I, III, IV and V, 22 for mitochondrial tRNA (for the 20 standard amino acids, plus an extra gene for leucine and serine), and 2 for rRNA.  One mitochondrion can contain two to ten copies of its DNA. Mitochondria & Chloroplast
  11. 11. Replication and Inheritance  Mitochondria divide by binary fission, similar to bacterial cell division  Mitochondria must be duplicated during cell cycle and segregated to the daughter cell  Replication of mtDna maybe stochastic Mitochondria & Chloroplast
  12. 12. Replication and Inheritance  Energy high-mitochondria grow and divide  Energy low-mitochondria destroyed and inactive  Most cases inherited only from mother which is known as maternal inheritance  Paternal inheritance may happen in some coniferous plants, some species and some insects. Mitochondria & Chloroplast When is replication not normal?
  13. 13. Mitochondrial Disease  Result from failures of the mitochondria  Less energy is generated within the cell. Cell injury and even cell death follow.  Genocopies of Mitochondrial Disease &Phenocopies of Mitochondrial Disease Mitochondria & Chloroplast
  14. 14. Mitochondrial Disease  Primarily affects children but adult onset is becoming more common.  Damage to cells of the brain, heart, liver, skeletal muscles, kidney and the endocrine and respiratory systems. Mitochondria & Chloroplast
  15. 15. Treatment  To alleviate symptoms and slow down the progression of the disease  Treatment may be beneficial and noted immediately in some disorders.  Sometimes, the benefits of treatment may take a few months to notice. Mitochondria & Chloroplast
  16. 16. Therapy  Dietary Therapy  Supportive Therapies  Avoidance of Toxins  Vitamins and Supplements That May Be Helpful  Medication, Minerals, Vitamins and Substrates That May Be Helpful  Avoidance of Physiologic "Stress" Mitochondria & Chloroplast
  17. 17. Possible Relationship to Aging  A number of changes can occur to mitochondria during the aging process  Tissues from elderly patients show a decrease in enzymatic activity of the proteins of the respiratory chain.  Mutated mtDNA can only be found in about 0.2% of very old cells. Mitochondria & Chloroplast
  18. 18. Possible Relationship to Aging  Large deletions have been hypothesized to lead high levels of oxidative stress and neuronal death in Parkinson's disease.  Mitochondrial changes are causes of aging or merely characteristics of aging. Mitochondria & Chloroplast
  19. 19. Chloroplast Mitochondria & Chloroplast
  20. 20. Chloroplast  Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis.  Cyanobacteria are considered the ancestors of chloroplasts. Mitochondria & Chloroplast
  21. 21. Primary endosymbiosis  A eukaryote with mitochondria engulfed acyanobacterium in an event of serial primary endosymbiosis, creating a lineage of cells with both organelles. The cyanobacterial endosymbiont already had a double membrane— thephagosomal vacuole-derived membrane was lost. Mitochondria & Chloroplast
  22. 22.  Many other organisms obtained chloroplasts from the primary chloroplast lineages through secondary endosymbiosis. Mitochondria & Chloroplast Chromatophores  Being in the early stages of endosymbiosis, Paulinella chromatophora can offer some insights into how chloroplasts evolved. Secondary and tertiary endosymbiosis
  23. 23.  In some groups of mixotrophic protists, chloroplasts are separated from a captured alga or diatom and used temporarily. These klepto chloroplasts may only have a lifetime of a few days and are then replaced. Mitochondria & Chloroplast Chloroplast DNA  Chloroplasts have their own DNA. Its also known as the Plastome. Its existence was 1st proved in 1962. Kleptoplastidy
  24. 24.  Most chloroplasts have their entire chloroplast genome combined into a single large ring. Inverted repeats: Chloroplast DNA contain 2 inverted repeats. 1. Long single copy section (LSC) 2. Short single copy section (SSC) Many nucleoids can be found in each chloroplast. Mitochondria & Chloroplast Protein synthesis  Protein synthesis within chloroplasts relies on two RNA polymerases. Molecular structure
  25. 25.  The movement of so many chloroplast genes to the nucleus means that lots of chloroplast proteins that were supposed to be translated in the chloroplast are now synthesized in the cytoplasm.  In most, but not all cases, nuclear-encoded chloroplast proteins are translated with a cleavable transit peptide that's added to the N-terminus of the protein precursor. Mitochondria & Chloroplast Protein targeting & import
  26. 26.  Outer chloroplast membrane  Inter-membrane space  Inner chloroplast membrane  Stroma  Pyrenoids  Thylakoid system Mitochondria & Chloroplast Structure
  27. 27.  Lipid composition  Phospholipids(48%)  Galactolipid(46%)  Sulfolipid(6%)  Semi-porous membrane  Sometimes forms Stromule Mitochondria & Chloroplast Outer chloroplast membrane Inter-membrane space  10-20 nanometers thick  Exists between outer & inner wall
  28. 28.  Lipid composition • Phospholipids(16%) • Galactolipids(79%) • Sulfolipids(5%)  Regulates passage of materials  Fatty acids, lipids, carotenoids are synthesized Mitochondria & Chloroplast Inner chloroplast membrane
  29. 29.  Colorless fluid surrounding grana  Protein rich  Location of chloroplast DNA & ribosomes  Calvin cycle takes place Mitochondria & Chloroplast Stroma
  30. 30.  Membrane bound compartment  Site of light-dependent reactions  Forms stack of disks(Grana)  Grana are connected by inter-grana thylakoids Mitochondria & Chloroplast Thylakoid system
  31. 31.  Chloroplasts use Rubisco  Trouble distinguishing oxygen & carbon dioxide  C4 plants evolved a solution  Separating light reactions & Calvin cycle Mitochondria & Chloroplast Specialized chloroplast in c4 plants
  32. 32.  Distribution in plants  Cellular location Mitochondria & Chloroplast Location Distribution in a plant  All green parts contain chloroplast  Usually parenchyma cells  Can be found in collenchyma tissue  Known as Chlorenchyma cell  Concentrated in leaves
  33. 33.  Can change orientation  Low light condition • Spread out in a sheet  Intense light • Aligns in vertical columns  Reduces exposure  Protects from photo-oxidative damage Mitochondria & Chloroplast Cellular location
  34. 34.  Plant innate immunity  Hypersensitive response  Systemic Acquired Resistance  Photosynthesis:  Light reactions  Photophosphorylation  Dark reactions  pH level Mitochondria & Chloroplast Function and chemistry
  35. 35.  Plastid interconversion  Chloroplast division  Chloroplast Inheritance Mitochondria & Chloroplast Differentiation, replication and inheritance
  36. 36. Mitochondria & Chloroplast References  http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Chloroplasts.html  http://ccdb.ucsd.edu/sand/main?stype=lite&keyword=chloroplast&Submit=Go&e vent=display&start=1  http://www.mitodb.com/  http://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/EMMitoE.html  http://www.cytochemistry.net/Cell-biology/mitoch1.htm