Mitochondrial genetics Flashcards
what is the mitochondria responsible for
apoptotic cell death, intracellular signalling, lipid metabolism, thermogenesis, cellular energy production
How does OXPHOS ATP production work
ref. notes
Describe properties of mitochondria DNA
circular and contains genes coding for protein of the OXPHOS chain (13 polypeptides, 22 transfer RNAs, 2 ribosomal RNAs)
What is homoplasmy and heteroplasmy
Homoplasmy–all copies re identical (can also reefer to position in the genomee)
heteroplasmyy-more than one type of MT genome present (or variation at position)
Where are the proteins forming parts of the OXPHOS chain derived from
nuclear genome
what are nuclear derived proteins responsible for
replication and repair of mitochondrial genome
transcription and processing of mitochondrial genome as well as being involved in translation
what do nuclear and mitochondrial genome do and what are they both essential for
interact, essential for cellular energy production
where are the origins of mitochondrial diseases
could be nucleus and/or mitochondria
What are the general features of mitochondrial disorders
respiratory chain defiiciency
leads to reduction in cellular oxygen consumption and ATP synthessis
patients often have increased lactic acid build up in blood and cerebral fluid
sometimes ATP production may not be affected but instead overproduction of reactive oxygen species
which parts of the body can mitochondrial diseases affedct
CNS, cardiac, renal, endocrine+diabetes, PNS, gastrointestinal, hearing, eye
what kind of tissues are most affected by mitochondrial disorders
ones with high energy demand (brain/heart/kidney/skeletal muscle), frequently involving neuromuscular system
What are the 3 causes of mitochondrial diseases
nuclear origin
nuclear origin with mitochondrial dysfunction
mitochondrial origin
What are mitochondrial disease caused by nuclear genome mutations caused by and what are examples of these
follow same inheritance pattern as Mendelian disorders
can be causeed by defects to genes involved in replication, transcription, translation and repair of MT DNA
e.g. Friedreich Atoxia autosomal recessive
What are mitochondrial disease caused by nuclear genome mutations with mitochondrial dysfunction caused by and what are examples of these
defects in genes that monitor and regulate mitochondrial, requires mitochondrial dysfunction, important in ageing
e.g. Parkinson’s. Parkin and PINK1 involved. PINK1 nnormally imported into mitochondria, cleaved and released->in damaged MT causing depolarisation of membranes, PINK1 accumulates in outer memb and Parkin recruited to mitochondria and triggers autophagy
What are mitochondrial disease caused by mitochondrial genome mutations caused by and what are examples of these
caused by point mutations ore rearrangements, similar general features to disorders caused by nuclear mutations, inherited from mother.
e.g. Levber’s hereditary . sub acute loss of central vission. Caused by homoplasmic mutation
