Graph View

Backlinks

The Library

Search

SearchSearch

Mitochondrion

Sep 25, 2024, 2 min read

Mitochondrial Structure

  • The mitochondria probably arose from an aerobic bacterium that was ingested by an anaerobic host cell
  • Mitochondria can fuse into one another or split into two.
  • They are often associated with fatty acid-containing oil droplets from which they derive materials to be oxidized.

Membranes

  • An outer boundary membrane which encloses the mitochondrion. Generally, this has a lot of lipids and contain porins.
  • The inner boundary membrane that forms a double-layer membrane with the outer membrane. Generally, this has a lot of proteins, is devoid of cholesterol and rich in cardiolipin.
    • The permeability of this membrane is important in maintaining the protein gradient. If it is more permeable, it loses more energy to heat.
    • This is also the site of ATP Synthase.
      • ATP synthase consists of two parts—one which hydrolyzes ATP and another which conducts protons from the intermembrane space to the matrix.
      • ATP synthase is effectively a rotary motor.
  • The intermembrane space is the space between the outer and inner membrane.
  • The cristae which consist of folded membranous sheets that act to increase the surface area of the mitochondrion.
  • The cristae junctions which join the inner boundary with the cristae.

Matrix

  • The matrices are interior compartments located within the mitochondrion.
  • These have a gel-like consistency due to high concentration of water-soluble proteins.
  • These also contain ribosomes and mitochondrial DNA and RNA.
    • These facilitate the manufacturing of the most hydrophobic proteins of the inner membrane.

Functions

  • ATP production and metabolism.
  • Sites of synthesis for various substances.
  • Regulation of ion concentrations within the cytosol.
  • Proteins in the intermembrane space facilitate cell suicide.

Human Impact

  • Abnormalities in the mitochondria typically result in muscle or brain degradation. These tissue consume a lot of ATP.
    • This may result in other conditions such as abnormal muscle fibers or loss of senses.
    • Interestingly, these conditions are inherited maternally.
  • The flow of the electron transport chain also contributes to free radicals within the cell which causes mitochondrial DNA to be more susceptible to mutation. These might constitute premature aging, but not be relevant for normal aging.

Links