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This division and segregation process must be tightly controlled so that each daughter cell receives at least one mitochondrion. In other eukaryotes (in mammals for example), mitochondria may replicate their DNA and divide mainly in response to the energy needs of the cell, rather than in phase with the cell cycle.
Mitochondrial replication is controlled by nuclear genes and is specifically suited to make as many mitochondria as that particular cell needs at the time. Mitochondrial transcription in humans is initiated from three promoters , H1, H2, and L (heavy strand 1, heavy strand 2, and light strand promoters).
Mitochondrial fission is the process by which mitochondria divide or segregate into two separate mitochondrial organelles. Mitochondrial fission is counteracted by mitochondrial fusion, where two mitochondria fuse together to form a larger one. [1] Fusion can result in elongated mitochondrial networks.
The ability for a mitochondrion to self-replicate is rooted in its evolutionary history. It is commonly thought that mitochondria descend from cells that formed endosymbiotic relationships with α-protobacteria; they have their own genome for replication. [5] However, recent evidence suggests that mitochondria may have evolved without symbiosis ...
Mitochondrial DNA is the small circular chromosome found inside mitochondria. These organelles, found in all eukaryotic cells, are the powerhouse of the cell. [1] The mitochondria, and thus mitochondrial DNA, are passed exclusively from mother to offspring through the egg cell.
Mitochondria and chloroplasts: generate energy for the cell. Mitochondria are self-replicating double membrane-bound organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells. [ 2 ]
As this cell divides, the mitochondria replicate and independently assort into the daughter cells. This leads to both positive and negative (cell shown in red) homoplasmy. Homoplasmy is a term used in genetics to describe a eukaryotic cell whose copies of mitochondrial DNA are all identical. [ 1 ]
The genes located in mitochondria and chloroplasts are very important for proper cellular function. The mitochondrial DNA and other extranuclear types of DNA replicate independently of the DNA located in the nucleus, which is typically arranged in chromosomes that only replicate one time preceding cellular division. The extranuclear genomes of ...