WEEK 11 (Mitochondria)

Question 1

Is there a link between mtDNA mutations and cancer?

Answer 1

YES

Explanation: There is data suggesting that many chemical carcinogens have significant mutation effects on mtDNA

Question 2

Describe the link between progressive decline of mitochondrial function and the ageing process

Answer 2

The accumulation of SPORADIC MUTATIONS in mtDNA leads to an increased prevalence of defective mitochondria (and thus supply of ATP) over time -> Cella require a threshold level of ATP production resulting from oxidative phosphorylation for normal function -> When the level drops below this threshold, the ageing process is accelerated

Question 3

What are deletions in mtDNA and electron transport abnormalities linked to?

Answer 3

Atrophied muscle fibers

Question 4

Are there any cures for mtDNA-based genetic disorders?

Answer 4

NO

Explanation: There are no cures but new therapeutic approaches are being developed that can prevent transmission of mtDNA mutations from an affected mother to her offspring

Question 5

Name a therapeutic approach to mtDNA-based genetic disorders

Answer 5

Mitochondrial replacement therapy (MRT) or three-parent in vitro fertilisation

Question 6

What happened in 2010?

Answer 6

Scientists demonstrated that the mtDNA genome can be replaced in the eggs of a nonhuman primate, the rhesus monkey

Question 7

Describe the process of Mitochondrial replacement therapy (MRT) or three-parent in vitro fertilisation

Answer 7

1) The nuclear genome from an egg of one mother is translated to an enucleated recipient egg of another female with a normal content of mitochondria
2) Reconstructed eggs were fertilised and implanted in the uterus of the original mother
3) Result is the production of a three-parent offspring [containing nuclear DNA from the transplanted maternal nuclear genome of one female, mitochondria from the recipient egg of another female and a paternal genome from the sperm donor]