Mitochondria use different origin sequences to initiate replication of each DNA strand

Replication of the H strand is initiated in a D loop.

Replication of the L strand is initiated when its origin is exposed by the movement of the first replication fork.

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#Unit 2. Cellular Organization

Linking number is topological property which is expressed as  Total No. of Base Pair/Base pair per turn.

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#Unit 2. Cellular Organization

How to calculate linking number?

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#Unit 2. Cellular Organization

If Lk <Lk0 and DLk is <0 means negative, then the DNA is said to be “negatively supercoiled.”

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#Unit 2. Cellular Organization

Conversely, if Lk >Lk0  and DLk >0 means positive, then the DNA is “positively supercoiled.”

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#Unit 2. Cellular Organization

Superhelical Density 

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#Unit 2. Cellular Organization

Circular DNA molecules purified from both bacteria and eukaryotes are usually negatively supercoiled, having values of s of approximately –0.06.