Like mitochondria, chloroplasts also contain their own DNA and are able to grow and reproduce independently within the cell. In most animal species, mitochondria appear to be primarily inherited through the maternal lineage, though some recent evidence suggests that in rare instances mitochondria may also be inherited via a paternal route. Typically, a sperm carries mitochondria in its tail as an energy source for its long journey to the egg. When the sperm attaches to the egg during fertilization, the tail falls off.
Consequently, the only mitochondria the new organism usually gets are from the egg its mother provided. Therefore, unlike nuclear DNA, mitochondrial DNA doesn't get shuffled every generation, so it is presumed to change at a slower rate, which is useful for the study of human evolution.
Mitochondrial DNA is also used in forensic science as a tool for identifying corpses or body parts, and has been implicated in a number of genetic diseases, such as Alzheimer's disease and diabetes. License Info. Image Use. Custom Photos. Site Info. Contact Us. The Galleries:. Photo Gallery.
Silicon Zoo. Chip Shots. DNA Gallery. Amino Acids. Religion Collection. Cocktail Collection. Screen Savers. Yet when the researchers looked using electron microscopy, they were able to see things that looked like mitochondria, having its typical layered membrane structure, including a series of folds in the innermost membrane.
This is not completely unexpected; as mentioned above, some single-celled parasites that no longer have mitochondria that perform oxidative metabolism still build similar-looking structures that handle other metabolic functions. To get a sense of what may be possible in Henneguya salminicola , the researchers looked for genes that encode components of the electron transport chain that helps make ATP. Most of those appear to be absent from this organism, indicating that whatever this structure is doing, it's not making ATP.
In many of the single-celled parasites, the mitochondrial remnant releases hydrogen; the genes needed to do that appear to be absent as well. So, the function of the mitochondrial remnant remains unclear at this point. But it is possible to speculate how this ended up being the only known animal species without functioning mitochondria.
When in fish, the organism takes up residence in the white muscles, which apparently function using anaerobic metabolism. While it's not clear what the second host is, plenty of worm options also live in anaerobic environments.
So, it's entirely possible that this organism was spending most of its existence without any oxygen to use for metabolism in the first place. Parasitic species like Henneguya salminicola often lose features because the species they attack provides so much for them.
If this organism rarely sees much oxygen, then losing the genes needed to perform oxygen-dependent reactions would be the expected outcome. It's also possible that having a smaller genome and less complicated internal structure would be evolutionarily favorable for these organisms. Does this discovery mean that we should rethink the need for oxygen-based metabolisms as a prerequisite for animal life?
Not entirely. It's pretty clear that these organisms would have a hard time surviving without animal hosts to provide many of the things we normally associate with more complicated organisms.
So, it's entirely possible that the oxygen-based metabolism enabled by complicated cells remains essential for the origin of animals. It's only after those animals exist that it may be dispensable.
Skip to content Home Cover Letter Can a plant cell survive without a mitochondria? Cover Letter. Ben Davis March 21, Can a plant cell survive without a mitochondria? Why do plant cells need mitochondria?
Why do we need mitochondria? What helps mitochondria do its job? What do mitochondria need to survive? Would an animal be able to survive without mitochondria? What if mitochondria is removed from the cell? Where is the mitochondria in a plant cell? How many mitochondria are in a plant cell? Do plant or animal cells have more mitochondria? Which organs have the most mitochondria? Do plant cells have less mitochondria than animal cells?
What animal cells have a lot of mitochondria?
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