Mitochondria and chloroplasts
E. nucleoids. B. ribosomes. 5. The evolutionary process that created chloroplasts and mitochondria is: A. punctuated equilibrium. B. endosymbiosis. C. evolution.and the full pname com svox langpack installer watch how i met your mother season 5 episode 10
NCBI Bookshelf. Cooper GM. The Cell: A Molecular Approach. Sunderland MA : Sinauer Associates; Cells are divided into two main classes, initially defined by whether they contain a nucleus. Prokaryotic cells bacteria lack a nuclear envelope ; eukaryotic cells have a nucleus in which the genetic material is separated from the cytoplasm.
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The cell of eukaryotic organisms animals, plants, fungi differs from that of prokaryotic organisms Archaea and Bacteria by the presence of several specialized organelles, such as: the nucleus containing the genetic information of the cell , the mitochondria site of cellular respiration , or the chloroplast site of photosynthesis in plants. The existence and organization of mitochondrial and chloroplast DNA, as well as their biochemistry and some structural traits, have led to their being considered as ancient bacteria integrated into a host cell by an endosymbiosis process. One possible hypothesis would be that current eukaryotes would descend from an archaeal ancestor who acquired a proteobacteria, the present mitochondria. Once this step was established, some cells would have incorporated cyanobacteria that are the origin of the chloroplast. At the same time, they have acquired the ability to carry out photosynthesis, and thus an autotrophic metabolism, a particularity of plants. Throughout the process, gene transfer phenomena between symbionts, the taking over of the coding of some organelle proteins by the nucleus and the relocation of gene products into the organelles have closely integrated these prokaryotes within the host cell. The phenomenon of endosymbiosis is therefore very largely responsible for the biodiversity of eukaryotes that appeared during evolution.
The evolutionary process that created chloroplasts and mitochondria is: B. Endosymbiosis. 6. Microfilaments such as actin, microtubules, and the intermediate.
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More Information About This Text. Mitochondria evolved by endosymbiosis. How did a situation evolve in which an organelle contains genetic information for some of its functions, while others are coded in the nucleus? Figure 3. At this point, the proto-organelle must have contained all of the genes needed to specify its functions. Sequence homologies suggest that mitochondria and chloroplasts evolved separately, from lineages that are common with eubacteria, with mitochondria sharing an origin with a -purple bacteria, and chloroplasts sharing an origin with cyanobacteria. The closest known relative of mitochondria among the bacteria is Rickettsia the causative agent of typhus , which is an obligate intracellular parasite that is probably descended from free-living bacteria.
Symbiosis and evolution: at the origin of the eukaryotic cell
Mitochondria, Chloroplasts, and the Endosymbiotic Theory
This page has been archived and is no longer updated. How do cells accomplish all their functions in such a tiny, crowded package? Eukaryotic cells — those that make up cattails and apple trees, mushrooms and dust mites, halibut and readers of Scitable — have evolved ways to partition off different functions to various locations in the cell. In fact, specialized compartments called organelles exist within eukaryotic cells for this purpose. Different organelles play different roles in the cell — for instance, mitochondria generate energy from food molecules; lysosomes break down and recycle organelles and macromolecules ; and the endoplasmic reticulum helps build membranes and transport proteins throughout the cell.