5. Cell Structure And Organization - part 10 - Glyoxysomes and Mitochondria

 


5. Cell Structure And Organization - part 10 - Glyoxysomes and Mitochondria


Glyoxysomes :


  • These membrane bound organelles contain enzymes that convert fatty acids to sugar. 
  • They can be observed in cells of germinating seeds where the cells utilise stored fats as source of sugar till it starts photosynthesising on its own.

Mitochondria (Singular :Mitochondrion) :

  • These are important cell organelles involved in aerobic respiration. 
  • Mitochondria are absent in prokaryotic cells and red blood corpuscles (RBCs). 
  • Their shape may be oval or spherical or spiral strip like.
  • It is a double membrane bound organelle. 
  • Outer membrane is permeable to various metabolites due to presence of a protein -Porin or Parson’s particles. 
  • Inner membrane is selectively permeable to few substances only. 
  • Both membranes are separated by a spaceouter chamber.
  • Inner membrane shows several finger like or plate like folds- cristae. 
  • Inner membrane bears numerous particles- oxysomes and cytochromes / electron carriers.
  • Inner membrane encloses a cavity- inner chamber, containing a fluid- matrix. 
  • Matrix contains few coils of -  
  1. circular DNA
  2. RNA
  3. 70S types of ribosomes
  4. lipids and 
  5. various enzymes of Krebs cycle and other pathways.

Oxysomes :

  • Inner membrane of mitochondria bears numerous particles - Oxysomes (F1-F0 / Fernandez - Moran / Elementary particles / mitochondrial particles). 
  • Each particle consists of head and stalk / foot. 
  • Head (F1) / lollipop head faces towards matrix and foot (F0) is embedded in inner membrane. Head acts as an enzyme ATP synthase and foot as proton channel. 
  • Oxysomes are involved in proton pumping and ATP synthesis.

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