Search results
Results From The WOW.Com Content Network
Mitochondria in both plant and animal cells perform respiration; the release of this stored energy when work is done. In addition to these key reactions of bioenergetics, chloroplasts and mitochondria each contain specialized and discrete genetic systems. These genetic systems enable chloroplasts and mitochondria to make some of their own proteins.
In biology, electrochemical gradients allow cells to control the direction ions move across membranes. In mitochondria and chloroplasts, proton gradients generate a chemiosmotic potential used to synthesize ATP, [1] and the sodium-potassium gradient helps neural synapses quickly transmit information. [citation needed]
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.
Mitochondria and plastids contain their own ribosomes; these are more similar to those of bacteria (70S) than those of eukaryotes. [77] Proteins created by mitochondria and chloroplasts use N-formylmethionine as the initiating amino acid, as do proteins created by bacteria but not proteins created by eukaryotic nuclear genes or archaea. [78] [79]
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 ...
Unlike the IMS of the mitochondria, the IMS of the chloroplast does not seem to have any obvious function. The translocase of the outer membrane and the translocase of the inner membrane mainly assist the translocation of chloroplast precursor proteins [10] Chaperone involvement in the IMS has been proposed but still remains uncertain.
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.
Experimentation with respiratory oxidase inhibitors (for instance, cyanide) on unicellular algae has revealed interactive pathways to be present between chloroplasts and mitochondria. Metabolic pathways responsible for photosynthesis are present in chloroplasts, whereas respiratory metabolic pathways are present in mitochondria.