Mitochondrial Myopathies Flashcards
What did mitochondria evolve from?
- bacteria
How is mitochondrial DNA organised and how many copies does each mitochondria posses?
- circular (DNA is double helix)
- hundreds of copies in each matric of mitochondria
Mitochondria are maternally inherited, what does this mean?
- only passed on my mother
- mitochondria in sperm do not enter the egg, if they do the =y are destroyed
In each mitochondria there are 5-10 copies of each mitochondrial DNA. How is the mtDNA organised?
- closed circular double stranded molecule
How large is the human mitochondria genome?
- 16.5 thousand base pairs
Are the majority of mitochondrial proteins produced by nuclear or mitochondrial DNA?
- nuclear
- proteins created in cytosol and transported into mitochondria
Although a lot of the mitochondrial genes have evolved into the nuclear DNA, how many respiratory proteins are encoded within the mitochondrial genome?
- 13
- complexs in electron transport chain etc..
Although a lot of the mitochondrial genes have evolved into the nuclear DNA, the mitochondrial genome still codes for 13 of the respiratory proteins. As mitochondria contain their own genes for respiratory proteins they also need their own transcription and translation processes. How many ribosomal RNA (rRNA) and transcriptomic RNA (tRNA) does the mitochondrial genome code for?
- 2 rRNA (synthesises proteins)
- 22tRNA (involved in protein translation)
The respiratory chain, also known as the electron transport chain is the main producer of ATP, but is also the main producer of what dangerous products?
- reactive oxygen species
The respiratory chain, also known as the electron transport chain is the main producer of reactive oxygen species in the mitochondria. Due to this what in the mitochondria can be damaged due to the close exposure?
- mitochondrial genome
- mtDNA less effective at correcting mistakes and repairing mt DNA damage
The respiratory chain, also known as the electron transport chain is the main producer of reactive oxygen species (ROS) in the mitochondria. Due to this the mt genome can be damaged by the ROS, and mtDNA becomes less effective at correcting mistakes and repairing mt DNA damage. What can this then cause and in which patients is this most common?
- increases risk of defects and mt mutations
- mtDNA defects accumulate with age
- mt DNA mutates more rapidly (x 10-fold) than nuclear DNA
Reactive oxygen species (ROS) can be created in the mitochondria, where will the majority of these ROS be created?
- electron transport chain in matrix and intermembrane space
- especially in complexes 3 and 4
Reactive oxygen species (ROS) can be created in the mitochondria, why are ROS created?
- electrons move to where they should not be
What happens to oxidation respiration as we age?
- declines in function
- in part due to mtDNA mutation accumulation
What is a common link between Alzheimer’s / Parkinson’s and type II diabetes in relation to the mitochondria?
- oxidative phosphorylation enzyme defects