Mitochondria

• About 900 proteins are imported into the mitochondria from nuclear DNA
• Mitochondrial DNA replication, transcription and protein synthesis occurs in the matrix
• Mitochondrial proteins are not exported out of the mitochondria
• The amount of mitochondrial DNA varies, however the mitochondria can increase its DNA content if needed
• Mitochondrial DNA is distributed in several clusters called nucleoids
• The size of this nucleoid differs in each organism
• Mitochondria are split randomly in daughter cells
• Some can inherit more copies of mutant or wild-type mtDNA
• Mitochondrial disease


  Can be inherited or acquired
• Inherited mitochondrial disease


  • Damage in the mtDNA
  • Damage in the nuclear genome
• Acquired mitochondrial disease


  • Damage of mtDNA
  • Damage of proteins
• Mitochondrial disease can affect oxidative phosphorylation reducing ATP production
• Muscular diseases can occur due to mitochondrial abnormalities giving symptoms of muscle weakness, cramps, stiffness and spasms
• There is no cure for mitochondrial diseases however there is treatment to reduce the symptoms and prevent progression
• Mitochondrial DNA affect ageing as it causes production of reactive oxygen species which cause aging
• Animals and humans with homozygous mutant mtDNA age faster