Protein synthesis within chloroplasts relies on two RNA polymerases. One is coded by the chloroplast DNA, the other is of nuclear origin. The two RNA polymerases may recognize and bind to different kinds of promoters within the chloroplast genome. The ribosomes in chloroplasts are similar to bacterial ribosomes Jun 29, · The first person to argue that DNA produces RNA which in turn leads to protein synthesis was André Boivin, in The first suggestion that small RNA molecules move from the nucleus to the cytoplasm and associate with ribosomes where they drive protein synthesis was made by Raymond Jeener, in Apr 15, · Please use one of the following formats to cite this article in your essay, paper or report: APA. Ryding, Sara. (, April 15). How to Store DNA
Phylogenetics - Wikipedia
They then use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesismuch amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to in plants like Arabidopsis and wheat. A chloroplast is a type of organelle known as a plastidcharacterized by its two membranes and a high concentration of chlorophyll.
Other plastid types, such as the leucoplast and the chromoplastcontain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulate and are moved around within plant cells, and occasionally pinch in two to reproduce. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts, like mitochondriacontain their own DNAwhich is thought to be inherited from their ancestor—a photosynthetic cyanobacterium dna rna and protein synthesis essay was engulfed by an early eukaryotic cell.
With one exception the amoeboid Paulinella chromatophoraall chloroplasts can probably be traced back to a single endosymbiotic eventwhen a cyanobacterium was engulfed by the eukaryote. Despite this, chloroplasts can be found in an extremely wide set of organisms, some not even directly related to each other—a consequence of many secondary and even tertiary endosymbiotic events.
The word chloroplast is derived from the Greek words chloros χλωρόςwhich means green, and plastes πλάστηςwhich means "the one who forms". The first definitive description of a chloroplast Chlorophyllkörnen"grain of chlorophyll" was given by Hugo von Mohl in as discrete bodies within the green plant cell. Chloroplasts are one of many types of organelles in the plant cell. They are considered to have evolved from endosymbiotic cyanobacteria.
Mitochondria are thought to have come from a similar endosymbiosis event, where an aerobic prokaryote was engulfed. Chloroplasts are considered endosymbiotic Cyanobacteria. They are a diverse phylum of bacteria capable of carrying out photosynthesisand are gram-negativemeaning that they have two cell membranes. Cyanobacteria also contain a peptidoglycan cell wallwhich is thicker than in other gram-negative bacteria, and which is located between their two cell membranes.
Somewhere between 1 to 2 billion years ago, [19] [20] [21] a free-living cyanobacterium entered an early eukaryotic cell, either as food or as an internal parasite[10] dna rna and protein synthesis essay managed to escape the phagocytic vacuole it was contained in. This event is called endosymbiosisor "cell living inside another cell with a mutual benefit for both".
The external cell is commonly referred to as dna rna and protein synthesis essay host while the internal cell is called the endosymbiont. Chloroplasts are believed to have arisen after mitochondriasince all eukaryotes contain mitochondria, but not all have chloroplasts.
Whether or not primary chloroplasts came from a single endosymbiotic event, or many independent engulfments across various eukaryotic lineages, has long been debated. It is now generally held that organisms with primary chloroplasts share a single ancestor that took in a cyanobacterium — million years ago.
These chloroplasts, which can be traced back directly to a cyanobacterial ancestor, are known as primary plastids [32] " plastid " in this context means almost the same thing as chloroplast [10]. All primary chloroplasts belong to one of four chloroplast lineages—the glaucophyte chloroplast lineage, the amoeboid Paulinella chromatophora lineage, the rhodophyte red algal chloroplast lineage, or the chloroplastidan green chloroplast lineage.
Usually the endosymbiosis event is considered to have occurred in the Archaeplastidawithin which the glaucophyta being the possible earliest diverging lineage.
Glaucophyte chloroplasts also contain concentric unstacked thylakoidswhich surround a carboxysome — an icosahedral structure that glaucophyte chloroplasts and cyanobacteria keep their carbon fixation enzyme RuBisCO in. The starch that they synthesize collects outside the chloroplast. The rhodophyteor red algae chloroplast group is another large and diverse chloroplast lineage.
Rhodoplasts have a double membrane with an intermembrane space and phycobilin pigments organized into phycobilisomes on the thylakoid membranes, preventing their thylakoids from stacking. The chloroplastida chloroplasts, or green chloroplasts, are dna rna and protein synthesis essay large, highly diverse primary chloroplast lineage. Their host organisms are commonly known as the green algae and land plants. Chloroplastida chloroplasts have lost the peptidoglycan wall between their double membrane, leaving an intermembrane space.
Green algae and plants keep their starch inside their chloroplasts, [16] [34] [37] and in plants and some algae, the chloroplast thylakoids are arranged in grana stacks. Some green algal chloroplasts contain a structure called a pyrenoid[16] which is functionally similar to the glaucophyte carboxysome in that it is where RuBisCO and CO 2 are concentrated in the chloroplast.
Dna rna and protein synthesis essay is a genus of nonphotosynthetic parasitic green algae that is thought to contain a vestigial chloroplast. While most chloroplasts originate from that first set of endosymbiotic events, Paulinella chromatophora is an exception that acquired a photosynthetic cyanobacterial endosymbiont more recently.
It is not clear whether that symbiont is closely related to the ancestral chloroplast of other eukaryotes. Chromatophores cannot survive outside their host. About 0. a It is now established that Chromalveolata is paraphyletic to Rhizaria, dna rna and protein synthesis essay.
Many other organisms obtained chloroplasts from the primary chloroplast lineages through secondary endosymbiosis—engulfing a red or green alga that contained a chloroplast. These chloroplasts are known as secondary plastids.
While primary chloroplasts have a double membrane from their cyanobacterial ancestor, secondary chloroplasts have additional membranes outside of the original two, as a result of the secondary endosymbiotic event, when a nonphotosynthetic eukaryote engulfed a chloroplast-containing alga but failed to digest it—much like the cyanobacterium at the beginning of this story.
The genes in the phagocytosed eukaryote's nucleus are often transferred to the secondary host's nucleus. All secondary chloroplasts come from green and red algae —no secondary chloroplasts from glaucophytes have been observed, probably because glaucophytes are relatively rare in nature, making them less likely to have been taken up by another eukaryote. Green algae have been taken up by the euglenidschlorarachniophytesa lineage of dinoflagellates[34] and possibly the ancestor of the CASH lineage cryptomonadsalveolatesstramenopiles and haptophytes [46] in three or four separate engulfments.
Euglenophytes are a group of common flagellated protists that contain chloroplasts derived from a green alga. Photosynthetic product is stored in the form dna rna and protein synthesis essay paramylonwhich is contained in membrane-bound granules in the cytoplasm of the euglenophyte. The ancestor of chlorarachniophytes is thought to have been a eukaryote with a red algal derived chloroplast.
It is then thought to have lost its first red algal chloroplast, and later engulfed a green alga, giving it its second, green algal derived chloroplast.
Chlorarachniophyte chloroplasts are bounded by four membranes, except near the cell membrane, where the chloroplast membranes fuse into a double membrane. Chlorarachniophyte chloroplasts are notable because the green alga they are derived from has not been completely broken down—its nucleus still persists as a nucleomorph [18] found between the second and third chloroplast membranes [16] —the periplastid spacewhich corresponds to the green alga's cytoplasm.
Lepidodinium viride and its close relatives are dinophytes see below that lost their original peridinin chloroplast and replaced it with a green algal derived chloroplast more specifically, a prasinophyte. The chloroplast is surrounded by two membranes and has no nucleomorph—all the nucleomorph genes have been transferred to the dinophyte nucleus. Cryptophytesor cryptomonads are a group of algae that contain a red-algal derived chloroplast.
Cryptophyte chloroplasts contain a nucleomorph that superficially resembles that of the chlorarachniophytes. They synthesize ordinary starchdna rna and protein synthesis essay, which is stored in granules found in the periplastid space —outside the original double membrane, in the place that corresponds to the red alga's cytoplasm.
Inside cryptophyte chloroplasts is a pyrenoid and thylakoids in stacks of two. Their chloroplasts do not have phycobilisomes[16] but they do have phycobilin pigments which they keep in their thylakoid space, rather than anchored on the outside of their thylakoid membranes.
Cryptophytes may have played a key role in the spreading of red algal based chloroplasts. Haptophytes are similar and closely related to cryptophytes or heterokontophytes.
The heterokontophytesalso known as the stramenopiles, are a very large and diverse group of eukaryotes. The photoautotrophic lineage, dna rna and protein synthesis essay, Ochrophytaincluding the diatoms and the brown algaegolden algae[35] and yellow-green algaealso contains red algal derived chloroplasts. Heterokont chloroplasts are very similar to haptophyte chloroplasts, containing a pyrenoidtriplet thylakoids, and with some exceptions, [16] having four layer plastidic envelope, the outermost epiplastid membrane connected to the endoplasmic reticulum.
Like haptophytes, heterokontophytes store sugar in chrysolaminarin granules in the cytoplasm. The alveolates are a major clade of unicellular eukaryotes of both autotrophic and heterotrophic members.
The most notable shared characteristic is the presence of cortical outer-region alveoli sacs. These are flattened vesicles sacs packed into a continuous layer just under the membrane and supporting it, typically forming a flexible pellicle thin skin. In dinoflagellates they often form armor plates. Many members contain a red-algal derived plastid, dna rna and protein synthesis essay. One notable characteristic of this diverse group is the frequent loss of photosynthesis.
However, a majority of these heterotrophs continue to process a non-photosynthetic plastid. Apicomplexans are a group of alveolates.
Like the helicosproidiadna rna and protein synthesis essay, they're parasitic, and have a nonphotosynthetic chloroplast. Many apicomplexans keep a vestigial red algal derived chloroplast [52] [34] called an apicoplastdna rna and protein synthesis essay, which they inherited from their ancestors.
Other apicomplexans like Cryptosporidium have lost the chloroplast completely. Apicoplasts have lost all photosynthetic function, and contain no photosynthetic pigments or true thylakoids. They are bounded by four membranes, but the membranes are not connected to the endoplasmic reticulum. Plant chloroplasts provide plant cells with many important things besides sugar, and apicoplasts are no different—they synthesize fatty acidsisopentenyl pyrophosphateiron-sulfur clustersand carry out part of the heme pathway.
The Chromerida is a newly discovered group of algae from Australian corals which comprises some close photosynthetic relatives of the apicomplexans. The first member, Chromera veliadna rna and protein synthesis essay, was discovered and first isolated in The discovery of Chromera velia with similar structure to the apicomplexanss, provides an important link in the evolutionary history of the apicomplexans and dinophytes.
Their plastids have four membranes, lack chlorophyll c and use the type II form of RuBisCO obtained from a horizontal transfer event. The dinoflagellates are yet another very large and diverse group of protistsaround half of which are at least partially photosynthetic. Most dinophyte dna rna and protein synthesis essay are secondary red algal derived chloroplasts.
Many other dinophytes have lost the chloroplast becoming the nonphotosynthetic kind of dinoflagellateor replaced it though tertiary endosymbiosis [54] —the engulfment of another eukaryotic algae containing a red algal derived chloroplast. Others replaced their original chloroplast with a green algal derived one. Most dinophyte chloroplasts contain form II RuBisCO, at least the photosynthetic pigments chlorophyll achlorophyll c 2beta -caroteneand at least one dinophyte-unique xanthophyll peridinindinoxanthindna rna and protein synthesis essay, or diadinoxanthingiving many a golden-brown color.
The most common dinophyte chloroplast is the peridinin -type chloroplast, characterized by the carotenoid pigment peridinin in their chloroplasts, along with chlorophyll a and chlorophyll c 2.
Starch is found outside the chloroplast. Most of the genome has migrated to the nucleus, and only critical photosynthesis-related genes remain in the chloroplast. The peridinin chloroplast is thought to be the dinophytes' "original" chloroplast, [48] which has been lost, reduced, replaced, or has company in several other dinophyte lineages. The fucoxanthin dinophyte lineages including Karlodinium and Karenia [34] lost their original red algal derived chloroplast, and replaced it with a new chloroplast derived from a haptophyte endosymbiont.
Karlodinium and Karenia probably took up different heterokontophytes. Fucoxanthin is also found in haptophyte chloroplasts, dna rna and protein synthesis essay, providing evidence of ancestry.
Some dinophytes, like Kryptoperidinium and Durinskia [34] have a diatom heterokontophyte derived chloroplast. The diatom endosymbiont has been reduced relatively little—it still retains its original mitochondria[34] and has endoplasmic reticulumribosomesa nucleusand of course, red algal derived chloroplasts—practically a complete cell[57] all inside the host's endoplasmic reticulum lumen.
DNA, RNA, and Protein Synthesis
, time: 31:01Chloroplast - Wikipedia
Apr 15, · Please use one of the following formats to cite this article in your essay, paper or report: APA. Ryding, Sara. (, April 15). How to Store DNA Unlock the secret code to DNA, the basis for all life on Earth! Jun 29, · The first person to argue that DNA produces RNA which in turn leads to protein synthesis was André Boivin, in The first suggestion that small RNA molecules move from the nucleus to the cytoplasm and associate with ribosomes where they drive protein synthesis was made by Raymond Jeener, in
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