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The traits encoded by this type of DNA, in animals, generally pass from mother to offspring rather than from the father in a process called cytoplasmic inheritance.This is due to the ovum provided from the mother being larger than the male sperm cell, and therefore has more organelles, where the organellar DNA is found.
Both organelles, the mitochondria and chloroplasts (in photosynthetic organisms), are compartments that are believed to be of endosymbiotic origin. Other compartments such as peroxisomes , lysosomes , the endoplasmic reticulum , the cell nucleus or the Golgi apparatus are not of endosymbiotic origin.
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.
In mitochondria, the PMF is almost entirely made up of the electrical component but in chloroplasts the PMF is made up mostly of the pH gradient because the charge of protons H + is neutralized by the movement of Cl − and other anions. In either case, the PMF needs to be greater than about 460 mV (45 kJ/mol) for the ATP synthase to be able to ...
Evidence suggests that mitochondria can also undergo fusion and exchange (in a form of crossover) genetic material among each other. Mitochondria sometimes form large matrices in which fusion, fission, and protein exchanges are constantly occurring. mtDNA shared among mitochondria (despite the fact that they can undergo fusion). [citation needed]
D-loop replication is a proposed process by which circular DNA like chloroplasts and mitochondria replicate their genetic material. An important component of understanding D-loop replication is that many chloroplasts and mitochondria have a single circular chromosome like bacteria instead of the linear chromosomes found in eukaryotes.
Three general types of extranuclear inheritance exist. Vegetative segregation results from random replication and partitioning of cytoplasmic organelles. It occurs with chloroplasts and mitochondria during mitotic cell divisions and results in daughter cells that contain a random sample of the parent cell's organelles.
A diagram of a chloroplast. The TIC and TOC complexes are located on different sides of the chloroplast membrane.. The TIC and TOC complexes are translocons located in the chloroplast of a eukaryotic cell, that is, protein complexes that facilitate the transfer of proteins in and out through the chloroplast's membrane.