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Variations in the structure of mitochondria

E W DEMPSEY

    The Journal of Biophysical and Biochemical Cytology
    |July 25, 1956
    PubMed

    Insights

    Mitochondria, vital cell organelles, possess a distinct internal structure visible via electron microscopy. Their dynamic nature suggests constant formation and destruction, but their precise origin remains unclear.

    Area of Science:

    • Cell Biology
    • Microscopy
    • Organelle Biology

    Background:

    • Mitochondria are essential cellular components with a defined internal structure.
    • Electron microscopy and light microscopy (using Janus green stain) are key identification methods.
    • Mitochondria exhibit pleomorphism, varying in size, shape, and density.

    Purpose of the Study:

    • To define mitochondria based on their characteristic internal structure for electron microscopy.
    • To explore the dynamic nature and potential turnover of mitochondria within cells.
    • To address the unresolved question of mitochondrial origin.

    Main Methods:

    • Utilizing electron microscopy to identify mitochondria by their double-layered outer wall and internal membranous folds.
    • Observing changes in mitochondrial number under controlled physiological conditions.
    • Reviewing existing hypotheses on mitochondrial formation, including fission and de novo synthesis.

    Main Results:

    • A characteristic internal structure provides a reliable definition for mitochondria in electron microscopy.
    • Mitochondria are labile, with numbers fluctuating, indicating dynamic processes.
    • New mitochondria form in specific physiological states, but the exact origin mechanism is uncertain.

    Conclusions:

    • The defined internal structure is a satisfactory basis for identifying mitochondria via electron microscopy.
    • The dynamic nature of mitochondria suggests continuous formation and degradation, possibly linked to metabolism.
    • Current understanding of mitochondrial origin is inadequate, with neither fission nor intracellular membrane synthesis fully substantiated.
    Keywords:
    MICROSCOPY, ELECTRONMITOCHONDRIA

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