The closed complex is converted into an open complex of 1.3 turns of the double helix in a series of steps by first “melting” a short region of DNA. 

This Isomerization is essentially irreversible and, once complete, typically guarantees that transcription will subsequently initiate.

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Mitochondrial segregation to daughter cells is also stochastic.

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#Unit 3. Fundamental Processes

When there are mtDNAs with allelic variations in the same cell, called heteroplasmy (either because of inheritance from different parents or because of mutation).

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#Unit 3. Fundamental Processes

Replication of mtDNA may be stochastic because there is no control over which particular copies are replicated, so that in any cycle some mtDNA molecules may replicate more times than others.

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#Unit 3. Fundamental Processes

A mitochondrion divides by developing a ring around the organelle that constricts to pinch it into two halves. The mechanism is similar in principle to that involved in bacterial division.

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#Unit 3. Fundamental Processes

The apparatus that is used in plant cell mitochondria is similar to that used in bacteria and uses a homolog of the bacterial protein FtsZ. 

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#Unit 3. Fundamental Processes

The molecular apparatus is different in animal cell mitochondria and uses the protein dynamin, which is involved in formation of membranous vesicles