Mitochondrial genetics Flashcards Preview

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Flashcards in Mitochondrial genetics Deck (20)
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1
Q

what is the mitochondria responsible for

A

apoptotic cell death, intracellular signalling, lipid metabolism, thermogenesis, cellular energy production

2
Q

How does OXPHOS ATP production work

A

ref. notes

3
Q

Describe properties of mitochondria DNA

A

circular and contains genes coding for protein of the OXPHOS chain (13 polypeptides, 22 transfer RNAs, 2 ribosomal RNAs)

4
Q

What is homoplasmy and heteroplasmy

A

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)

5
Q

Where are the proteins forming parts of the OXPHOS chain derived from

A

nuclear genome

6
Q

what are nuclear derived proteins responsible for

A

replication and repair of mitochondrial genome

transcription and processing of mitochondrial genome as well as being involved in translation

7
Q

what do nuclear and mitochondrial genome do and what are they both essential for

A

interact, essential for cellular energy production

8
Q

where are the origins of mitochondrial diseases

A

could be nucleus and/or mitochondria

9
Q

What are the general features of mitochondrial disorders

A

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

10
Q

which parts of the body can mitochondrial diseases affedct

A

CNS, cardiac, renal, endocrine+diabetes, PNS, gastrointestinal, hearing, eye

11
Q

what kind of tissues are most affected by mitochondrial disorders

A

ones with high energy demand (brain/heart/kidney/skeletal muscle), frequently involving neuromuscular system

12
Q

What are the 3 causes of mitochondrial diseases

A

nuclear origin
nuclear origin with mitochondrial dysfunction
mitochondrial origin

13
Q

What are mitochondrial disease caused by nuclear genome mutations caused by and what are examples of these

A

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

14
Q

What are mitochondrial disease caused by nuclear genome mutations with mitochondrial dysfunction caused by and what are examples of these

A

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

15
Q

What are mitochondrial disease caused by mitochondrial genome mutations caused by and what are examples of these

A

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

16
Q

What do the levels of heteroplasmy mean

A

low=no effect

meddium=milder symptom. Some mutations meaning that not producing funcctional protein for electron transport chain

17
Q

Even if one of the parent is a carrier of a mitochondrial defect, why do not all children present symptom

A

Differently % of mutant load

18
Q

What types of complex diseases may have association with mitochondrial mutation

A

alzheeimer’s, huntington’s, metabolic syndrome, myocardial infarction, parkinson’s, type 2 diabetes

19
Q

What kind of mitochondrial mutations are present in tumour cells

A

homoplasmic and heteroplasmic

20
Q

What is required in cancer development

A

functioning mitochondria for tumour cell development, functioning respiratory chain for pyrimidine synthesis of cell growth and proliferation