Mitocondrium replication
- Thread starter yaracuy
- Start date
Testing and enhancing my own understanding... check details against reliable sources.
It's the same mechanism, different specific protein.
A DNA polymerase is a big protein/enzyme/micromachine that duplicates DNA by unwrapping the double-stranded helix and building a new double helix from each single strand.
The DNA polymerase that duplicates mitochondrial DNA is not the same protein as the nuclear polymerase, but both are encoded from nuclear DNA (not sure if all different encoding, or some shared encoding), and both work in a similar way. I'm not sure exactly where the mtDNA polymerase is constructed. I'd guess that it's transported from the nucleus to the mitochondrion through the golgi apparatus.
The bits (nucleotides) that are used to build the new DNA strands are used for all kinds of stuff and pretty much everywhere... I think they're made in both the cytoplasm and in the nucleus (Nucleotide synthesis). They might also be made in the mitochondria, but if so I expect that they're made by enzymes encoded from nuclear DNA.
It's the same mechanism, different specific protein.
A DNA polymerase is a big protein/enzyme/micromachine that duplicates DNA by unwrapping the double-stranded helix and building a new double helix from each single strand.
The DNA polymerase that duplicates mitochondrial DNA is not the same protein as the nuclear polymerase, but both are encoded from nuclear DNA (not sure if all different encoding, or some shared encoding), and both work in a similar way. I'm not sure exactly where the mtDNA polymerase is constructed. I'd guess that it's transported from the nucleus to the mitochondrion through the golgi apparatus.
The bits (nucleotides) that are used to build the new DNA strands are used for all kinds of stuff and pretty much everywhere... I think they're made in both the cytoplasm and in the nucleus (Nucleotide synthesis). They might also be made in the mitochondria, but if so I expect that they're made by enzymes encoded from nuclear DNA.
The simple answer is binary fission.
Mitocondrium DNA uses the same mechanism to duplicate as the nuclear DNA?
Semi-conservative replication as per nuclear DNA. But as alluded to by Pete, I am unsure whether the mtDNA polymerases are encoded by nuclear or mitochondrial genes.
Any understanding of mitochondrion (mitochondrium) replication should review the endosymbiotic theory of their bacterial origin:
http://en.wikipedia.org/wiki/Endosymbiotic_theory
http://en.wikipedia.org/wiki/Endosymbiotic_theory
Fraggle Rocker
Staff member
I have encountered this idea before and it is quite intriguing. But judging from the article, it has not been accepted by the community of scientists so it is not part of the canon of science.
Therefore it is a friggin' hypothesis still undergoing testing and peer review, not a friggin' theory! I gnash my teeth when I see scientists not using their own terminology carefully. (And I don't mean that personally, you didn't coin the term.)
This falls into the same category as String "Theory."
And we wonder why laymen say, "Evolution is just a theory, and my bright 19 year-old son in his second year at Podunk State College will find the flaw in it."
I believe that most biologists are aware of this theory, and accept it as highly probable. If you look at the list of attributes (in the Wikipedia article - this is of course available elsewhere) of both mitochondria and plastids you will see how many are the same as for the bacteria and blue-green algae, respectively. What is not as widely accepted is that other organelles are likewise derived from bacterial-type symbiots, such as flagella, etc., though this an area of intense interest and research. This has been the state of knowledge in biology for decades (since at least the 1960s), and there has been continuing evidence in support of this, particularly from DNA studies showing gene transfer from organelles to the chromosomes, but still retaining those bacterial-type genes. (I use the term 'bacteria' loosely, meaning bacteria, blue-green algae, and other prokaryotes.)
What has been known since at least the 1960s is that the ribosomes of the organelles are bacterial size, rather than the size of ribosomes in eukaryote cytoplasm, and likewise the sub-units are quite similar to bacterial type sub-units, and unlike the subunits of ribosomes in the eukaryote cytoplasm. Likewise known since at least the 1960s is that the DNA of the organelles is separate from the chromosomes, is circular in shape like bacteria, and that the organelles manufacture their own proteins from this DNA and ribosome combination within the organelle. This entire process is so very similar to bacterial function that it is now generally accepted that the organelles are derived from such as endosymbionts in the early history of the eukaryotes. It might be possible that there are separate lineages within the eukaryotes, such as for the various types of algae (red, green, brown, diatoms, etc.), though I'm not certain if there is more work completed on that with which I'm not familiar. It is widely believed, however, that the land-plants have their chloroplasts derived from the green-algae chloroplasts.
Unless some other qualified biologist wishes to weigh in and assert that he/she doesn't believe so, I would assert that it is very widely accepted theory, as it is highly plausible and continuing evidence supports it.
Then either the article isn’t clear or you have misinterpreted the article because the endosymbiotic origin of mitochondria and chloroplasts is the accepted dogma of the significant majority of biological scientists. It’s in all the textbooks and it’s what is taught to college students. It is most definitely a theory; the endosymbiotic nature of these organelles beautifully explains their genetics, biochemistry, physiology and structure, and the flow of genes to/from the organelle and nuclear genomes has been used to predict the evolutionary relationship of eukaryotic organisms.
Is the Mitocondial DNA in a circle form ?
Does sends its ( m mit RNA) into Ribosome to form the necessary protein ?
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"Likewise known since at least the 1960s is that the DNA of the organelles is separate from the chromosomes, is circular in shape like bacteria, and that the organelles manufacture their own proteins from this DNA and ribosome combination within the organelle." From my post #6.
I don't understand your answer.
To ans amble proteine Eukaryotas use Ribosome machinery , does mitochondria use the same Ribosome to produce its necessary proteine ?
since we are talking symbiotic effect ?
"What has been known since at least the 1960s is that the ribosomes of the organelles are bacterial size, rather than the size of ribosomes in eukaryote cytoplasm, and likewise the sub-units are quite similar to bacterial type sub-units, and unlike the subunits of ribosomes in the eukaryote cytoplasm." Quote from my post #6.
'Bacterial' (used loosely), Mitochondrial and Plastid ribosomes are similar in size, and their sub-units are similar in size, and much smaller than the eukaryote ribosomes found in the cytoplasm of the eukaryote. There size is measured based upon their separation rate during centrifuging.
'Bacterial' (used loosely), Mitochondrial and Plastid ribosomes are similar in size, and their sub-units are similar in size, and much smaller than the eukaryote ribosomes found in the cytoplasm of the eukaryote. There size is measured based upon their separation rate during centrifuging.