Isn't that always the way with science; the more you learn the more questions you have.
Mitochondria
- Thread starter timojin
- Start date
Who said science is boring?
The DNA within mitochondria is useful because it allows the mitochondria to undergo something analogous to a cell division, where it can bud off daughter mitochondria. If it lost all its DNA to the nucleus, the mitochondria would not be able to bud, but would need to condense, using cytoplasm generated protein and nucleus generated DNA to act as the seed core.
If the nucleus had to release DNA, for mitochondria condensation, this action could lead to a virus effect, instead of a reliable engine. If the needed DNA mutated before it was released, you may not get a mitochondria condensing but something else? By retaining enough DNA to self replicate, the mitochondria keeps the nucleus from being a virus generator.
What is interesting, when cells undergo the cell cycle, the number of mitochondria increase so there is enough for two daughter cells. It appears the DNA in both the nucleus and the mitochondria are in equilibrium with the activity of the water, with the mitochondria having an easier time due to its small DNA.
If the nucleus had to release DNA, for mitochondria condensation, this action could lead to a virus effect, instead of a reliable engine. If the needed DNA mutated before it was released, you may not get a mitochondria condensing but something else? By retaining enough DNA to self replicate, the mitochondria keeps the nucleus from being a virus generator.
What is interesting, when cells undergo the cell cycle, the number of mitochondria increase so there is enough for two daughter cells. It appears the DNA in both the nucleus and the mitochondria are in equilibrium with the activity of the water, with the mitochondria having an easier time due to its small DNA.
Correct me if I misunderstood . Nucleus of the cell act independently of the nucleus of mitochondria, The nucleus of mitochondria generate its own daughter units for energy production . So both unit act independently. and the Nucleus and mitochondria have their own DNA. In a meiosis case the nuclear DNA splits the double strand , but the mitochondria becomes as a virus instead of unwinding.
Question : does the mitochondria DNA have a double helix ( double strand ).
Question : does the mitochondria DNA have a double helix ( double strand ).
Mitochondria are similar to bacteria. Their DNA is double helix, but not on chromosomes, but instead in a 'circle' array like in a bacterium. https://en.wikipedia.org/wiki/Mitochondrial_DNA
Interesting you mentioned in a circle array.
When a bacteria enters into a mammal in order to multiply itself does the circle opens and unfold the helix ?
Yazata
Valued Senior Member
Mitochondria don't have cell nuclei. Cell nuclei are only found in eucaryotic cells, the kind of cells in which one finds mitochondria. Protozoa, fungi, plants and animals are all comprised of eucaryotic cells. Just about all multi-cellular organisms consist of eucaryotic cells.
Mitochondria themselves more closely resemble procaryotic cells, whose representatives are bacteria and archaea. Procaryotic cells are smaller and simpler structurally (though not necessarily simpler biochemically) than eucaryotic cells. Many of the cellular structures ('organelles') found in eucaryotic cells, including a cell nucleus, aren't present in procaryotic cells, or in mitochondria.
https://en.wikipedia.org/wiki/Prokaryote
https://en.wikipedia.org/wiki/Eukaryote
The earliest life on earth seems to have been procaryotic. It seems to have appeared very early, perhaps right after the earth formed. Explaining that is one of the great mysteries of biology. For a long period, bacteria and archaea were apparently the only kind of life on earth. Then suddenly eucaryotic cells appeared. How, when and why that happened is another of biology's mysteries. Current speculation has it that the process that generated eucaryotic cells included (but wasn't restricted to) cells taking up residence inside other cells as endosymbionts. Mitochondria and plant chloroplasts (which also have their own DNA) are descendants of these.
Then at some point these more capable eucaryotic cells started to come together in multi-cellular organisms and the 'cambrian explosion' occurred, generating most of the body plans that we see in animals today. Coelenterates like starfish, a wide variety of worms both segmented and non-segmented, arthropods, chordates and molluscs appeared, all in a relatively short period of time. That's another of biology's mysteries. Though evidence now suggests that the explosion may have been due more to the evolution of hard body parts like shells that fossilize well than to all the familiar taxonomic categories of multicellular life appearing from single celled ancestors so quickly. There's growing evidence of an earlier period, prior to the 'cambrian explosion', when many early, experimental and in some cases abortive soft-bodied taxonomic types existed.
https://en.wikipedia.org/wiki/Ediacara_biota
Mitochondria don't reproduce independently. Most of the proteins that make up the mitochondrion are encoded in the chromosomes of the larger surrounding cell's nuclear genome, and manufactured in the larger cell's endoplasmic reticulum and Golgi apparatus. (More of those eucaryotic 'organelles'.) So the larger surrounding cell reproduces its mitochondria, just as it reproduces its other organelles. At best, the mitochondrion assists in its own reproduction.
Yes. But the mitochondrial DNA no longer has enough genes to fully reproduce a mitochondrion.
When people talk about it forming a ring in the same way that procaryotic bacterial DNA does, they aren't saying that it isn't a double helix. They are saying that the strand of double helix meets and fuses at its ends and forms a circle.
In eucaryotic cells, the double-stranded DNA is organized much more elaborately, into chromosomes.
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is it saying the double helix is no more but a single long strand equally in length of two double helix ?
the double-helix is always present. it is a long chain/string that comes back upon itself in a 'circle. when it duplicates, the double-helix opens up, allowing for base-pairs to match up, forming two circles of double-helix.
see also: https://en.wikipedia.org/wiki/Bacteria
This is to show you on how full of crap are you
http://www.npr.org/sections/health-shots/2016/05/12/477691018/look-ma-no-mitochondria
That doesn't address your OP:
As a matter of fact, it's entirely the opposite. Feel free to rave on.
As a matter of fact, it's entirely the opposite. Feel free to rave on.