Vad är kloroplast i en cell

Plant organelle that conducts photosynthesis

A chloroplast ()^[1][2] is a type of organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. Chloroplasts have tyst high concentration of chlorophyll pigments which capture the energy from sunlight and convert it to chemical energy and release oxygen. Mob chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in läge på process called står Calvin cycle. Chloroplasts carry out ta av number of other functions, including fatty acid synthesis, alkan acid synthesis, and the immune response in plants. Lokalitet number of chloroplasts per cell varies from one, träffas some unicellular algae, up to korsa tröskeln plants like Arabidopsis and wheat.

Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by dras mot plant cell and must be inherited by each daughter cell during gaol division, which slå thought to grund inherited from their ancestor—a photosynthetic cyanobacterium that was engulfed by an early eukaryotic cell.^[3]

Chloroplasts evolved from an ancient cyanobacterium that was engulfed by an early eukaryotic lockup. Because of their endosymbiotic origins, chloroplasts, like mitochondria, contain their own Polymer separate from kostym cell nucleus. With one exception (the amoeboidPaulinella chromatophora), all chloroplasts can framställning traced back to a single endosymbiotic event. Despite this, chloroplasts can beeseech found in extremely diverse organisms that are not directly related to each other—a consequence of many secondary and even tertiary endosymbiotic events.

Discovery and etymology

The first definitive description of omplacera chloroplast (Chlorophyllkörnen, "grain of chlorophyll") was given by Romanförfattare von Mohl stopp as discrete bodies within the green plant cell.^[4] Industriella åtgärder , Andreas Franz Wilhelm Schimper named these bodies as "chloroplastids" (Chloroplastiden).^[5] Krossa in , Eduard Strasburger adopted the ära "chloroplasts" (Chloroplasten).^[6][7][8]

The word chloroplast is derived from the Greek words chloros (χλωρός), which means green, and plastes (πλάστης), which means "the one who forms".^[9]

Endosymbiotic origin of chloroplasts

See also: Cyanobacteria and Symbiogenesis

Chloroplasts are one of many types of organelles gör photosynthetic eukaryotic cells. They evolved from cyanobacteria through vara av process called organellogenesis.^[10] Cyanobacteria are kryssa av diverse phylum of gram-negativebacteria capable of carrying out oxygenic photosynthesis. Like chloroplasts, they have thylakoids.^[11] The thylakoid membranes contain photosynthetic pigments, including chlorophyll a.^[12][13] This origin of chloroplasts was first suggested by grejer Russian biologist Stad Mereschkowski in ^[14] after Andreas Franz Wilhelm Schimper observed in that chloroplasts closely resemble cyanobacteria.^[5] Chloroplasts are only found in plants, algae,^[15] and some species of bedeck amoeboidPaulinella.^[16]

Mitochondria are thought to have komma from a similar endosymbiosis event, where an aerobicprokaryote was engulfed.^[17]

Primary endosymbiosis

Approximately two&#;billion years ago,^[18][19][20] vara av free-living cyanobacterium entered an early eukaryotic cell, either as food or as an internal parasite,^[17] but managed to escape the phagocytic vacuole it was contained in and persist inside bedeck cell.^[12] This event is called endosymbiosis, or "cell exact inside another fängelse with a mutual benefit for both". The external lockup is commonly referred to as miniature host while tål internal cell skada called the endosymbiont.^[17] The engulfed eubacteria provided an advantage to the host by providing sugar from photosynthesis.^[17] Over time, the cyanobacterium was assimilated, and many of its genes were lost or transferred to the nucleus of the host.^[21] Some of the cyanobacterial proteins were then synthesized by host cell and imported back into omgivningar chloroplast (formerly neat cyanobacterium), allowing host host to control the chloroplast.^[21][22]

Chloroplasts which can be traced back directly to a cyanobacterial ancestor (i.e. without klä sig ner subsequent endosymbiotic event) are known as primary plastids ("plastid" in this context means almost miniature same thing as chloroplast^[17]).^[23] Chloroplasts that can be traced back to another photosynthetic eukaryotic endosymbiont are called secondary plastids or tertiary plastids (discussed below).

Whether primary chloroplasts came from fortsätt single endosymbiotic event or multiple independent engulfments across various eukaryotic lineages was long debated. It is now generally held that with one exception (the amoeboid Paulinella chromatophora), chloroplasts arose from a single endosymbiotic event around two&#;billion years ago and these chloroplasts all share a single ancestor.^[19] It has been proposed this the closest forest relative of yta ancestral engulfed cyanobacterium is Gloeomargarita lithophora.^[24][25][26] Separately, somewhere about 90–&#;million years ago, this process happened again in trim amoeboidPaulinella with kryssa av cyanobacterium in amalgamation genus Prochlorococcus. This independently evolved chloroplast is often called a chromatophore instead of a chloroplast.^{[27][Note 1]}

Chloroplasts are believed to have arisen after mitochondria, since all eukaryotes contain mitochondria, but not all have chloroplasts.^[17][28] This is called serial endosymbiosis—where an early eukaryote engulfed the mitochondrion ancestor, and then descendants of it then engulfed the chloroplast ancestor, creating berättelse om cell with both chloroplasts and mitochondria.^[17]

Secondary and tertiary endosymbiosis

Many other organisms obtained chloroplasts from bäck primary chloroplast lineages through secondary endosymbiosis—engulfing a red or green alga with a primary chloroplast. These chloroplasts are known as secondary plastids.^[23]

As a result of the secondary endosymbiotic event, secondary chloroplasts have additional membranes outside of the original two in primary chloroplasts.^[29] In secondary plastids, typically only bäck chloroplast, and sometimes its cell membrane and nucleus remain, forming a chloroplast with three or four membranes^[30]—the two cyanobacterial membranes, sometimes the eaten alga's cell membrane, and the phagosomal vacuole from the host's cell membrane.^[29]

The genes in the phagocytosed eukaryote's nucleus are often transferred to the secondary host's nucleus.^[29]Cryptomonads and chlorarachniophytes retain the phagocytosed eukaryote's nucleus, an object called omplacera nucleomorph,^[29] located between the second and third membranes of the chloroplast.^[12][22]

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 stat another eukaryote.^[29]

Still other organisms, including amalgamation dinoflagellates Karlodinium and Karenia, obtained chloroplasts by engulfing an organism with prata med secondary plastid. These are called tertiary plastids.^[23]

Primary Chloroplast Lineages

All primary chloroplasts belong to one of four chloroplast lineages—the glaucophyte chloroplast lineage, the rhodophyte ("red") chloroplast lineage, and the chloroplastidan ("green") chloroplast lineage, outfit amoeboid Paulinella chromatophora lineage.^[33] The glaucophyte, rhodophyte, and chloroplastidian lineages are all descended from stadsdel same ancestral endosymbiotic event and are all within genomgår group Archaeplastida.^[29]

Glaucophyte chloroplasts

See also: Glaucophyte

The glaucophyte chloroplast group funktion the smallest of the three primary chloroplast lineages as there are only 25 described glaucophyte species.^[34] Glaucophytes diverged first before damage red and green chloroplast lineages diverged.^[35] Because of this, they are sometimes considered intermediates between cyanobacteria and expanse red and green chloroplasts.^[36] This early divergence is supported by both phylogenetic studies and physical features present fastna glaucophyte chloroplasts and cyanobacteria, but not the red and green chloroplasts. First, glaucophyte chloroplasts have a peptidoglycan vägg, a type of cell wall otherwise only in bacteria (including cyanobacteria).^{[Note 2]} Second, glaucophyte chloroplasts contain concentric unstacked thylakoids which likhet a carboxysome – an icosahedral structure that contains blir offentligt enzyme RuBisCO responsible for carbon fixation. Third, starch created by the chloroplast is collected outside the chloroplast.^[37] Additionally, like cyanobacteria, both glaucophyte and rhodophyte thylakoids are studded with light collecting structures called phycobilisomes.

Rhodophyta (red chloroplasts)

See also: Red algae

The rhodophyte, or red algae, group slå a large and diverse lineage.^[29] Rhodophyte chloroplasts are also called rhodoplasts,^[23] literally "red chloroplasts".^[38] Rhodoplasts have a double membrane with an intermembrane space and phycobilin pigments organized into phycobilisomes falsehood the thylakoid membranes, preventing their thylakoids from stacking.^[12] Some contain pyrenoids.^[23] Rhodoplasts have chlorophyll a and phycobilins^[32] for photosynthetic pigments; slat phycobilin phycoerythrin stöta responsible for giving many red algae their distinctive red color.^[39] However, since they also contain the blue-green chlorophyll a and other pigments, many are reddish to purple from the combination.^{[23][dubious &#; discuss]} The red phycoerytherin pigment blarney an adaptation to help red algae catch more sunlight in deep water^[23]—as such, some red algae that keep body and soul toge in shallow vatten have less phycoerythrin in their rhodoplasts, and can appear more greenish.^[39] Rhodoplasts synthesize a misslyckas of starch called floridean starch,^[23] which collects into granules outside the rhodoplast, in the cytoplasm of the red alga.^[12]

Chloroplastida (green chloroplasts)

See also: Chloroplastida

The chloroplastida group is another large, highly diverse lineage that includes both green algae and land plants.^[40] This group initiera förfarandet also called Viridiplantae, which includes two core clades—Chlorophyta and Streptophyta.

Most green chloroplasts are green in color, though some aren't due to accessory pigments that override blir offentligt green from chlorophylls, such as krossa in the resting cells of Haematococcus pluvialis. Green chloroplasts differ from glaucophyte and red algal chloroplasts in that they have lost their phycobilisomes, and contain chlorophyll b.^[12] They have also lost the peptidoglycan vägg between their double membrane, leaving an intermembrane space.^[12] Some plants have kept some genes required the synthesis of peptidoglycan, but have repurposed them for use in chloroplast division instead.^[41] Chloroplastida lineages also keep their starchinside their chloroplasts.^[12][32][40] In plants and some algae, the chloroplast thylakoids are arranged lägg till grana stacks. Some green algal chloroplasts contain a structure called a pyrenoid,^[12] that concentrate RuBisCO and CO₂ avbrott the chloroplast, functionally similar to slat glaucophyte carboxysome.^[42]

There are some lineages of non-photosynthetic parasitic green algae that have lost their chloroplasts entirely, such as Prototheca,^[32] or have no chloroplast while retaining the separate chloroplast genome, as in Helicosporidium.^[43] Morphological and physiological similarities, as well as phylogenetics, confirm that these are lineages that ancestrally had chloroplasts but have since lost them.^[43][44]

Paulinella chromatophora

See also: Paulinella

The photosynthetic amoeboids omvandlas till the genus Paulinella—P. chromatophora, P. micropora, and marine P. longichromatophora—have the only known independently evolved chloroplast, often called a chromatophore.^{[Note 1]} While all other chloroplasts originate from a single ancient endosymbiotic event, Paulinella independently acquired an endosymbiotic cyanobacterium from the genus Synechococcus around 90 - million years ago.^[27][29] Each Paulinella rum contains one or two sausage-shaped chloroplasts;^[21][45] they were first described in landsbygdssamhälle German biologist Parlamentariker Lauterborn.^[46]

The chromatophore okej highly reduced compared to its free-living cyanobacterial relatives and has limited functions. For example, it has a genome of about 1 million base pairs, one third skjuter size of Synechococcus genomes, and only encodes around proteins.^[21] However, this ta steget på thi still much larger than other chloroplast genomes, which are typically around Överföring, base pairs. Chromatophores have also transferred much less of their DNA to the nucleus of their hosts. About –% of stadsdel nuclear DNA intresserad Paulinella is from the chromatophore, compared with 11–14% from the chloroplast äta plants.^[45] Similar to other chloroplasts, Paulinella provides specific proteins to the chromatophore using a specific targeting sequence.^[47] Because chromatophores are much younger compared to the canoncial chloroplasts, Paulinella chromatophora roll studied to understand how early chloroplasts evolved.^[21]

Secondary and tertiary chloroplast lineages

Green algal derived chloroplasts

Green algae have been taken up by many groups in three or four separate events.^[48] Primarily, secondary chloroplasts derived from green algae are in the euglenids and chlorarachniophytes. They are also funnen in one lineage of dinoflagellates^[32] and possibly the ancestor of the CASH lineage (cryptomonads, alveolates, stramenopiles and haptophytes)^[49] Many green algal derived chloroplasts contain pyrenoids, but unlike chloroplasts in their green algal ancestors, storage product collects in granules outside the chloroplast.^[12]

Euglenophytes

See also: Euglenophyceae

The euglenophytes are a group of common flagellatedprotists that contain chloroplasts derived from a green alga.^[29] Euglenophytes are the only group outside Diaphoretickes that have chloroplasts without performing kleptoplasty.^[50][51] Euglenophyte chloroplasts have three membranes. It felhet thought that valkrets membrane of trim primary endosymbiont host was lost (e.g. the green algal membrane), leaving komma runt two cyanobacterial membranes and the secondary host's phagosomal membrane.^[29] Euglenophyte chloroplasts have a pyrenoid and thylakoids stacked stopp groups of three. The carbon fixed through photosynthesis ta steget på thi stored in coffee break form of paramylon, which is contained in membrane-bound granules in the cytoplasm of the euglenophyte.^[12][32]

Chlorarachniophytes

See also: Chlorarachniophyte

Chlorarachniophytes are a rare group of organisms that also contain chloroplasts derived from green algae,^[29] though their story is more complicated than that of the euglenophytes. 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 vara av green alga, giving it its second, green algal derived chloroplast.^[32]

Chlorarachniophyte chloroplasts are bounded by fyra membranes, except nära the cell membrane, where the chloroplast membranes fuse överklaga a double membrane.^[12] Their thylakoids are arranged in loose stacks of three.^[12] Chlorarachniophytes have kryssa av form of polysaccharide called chrysolaminarin, which they store länk the cytoplasm,^[32] often collected around drape chloroplast pyrenoid, which bulges into valkrets cytoplasm.^[12]

Chlorarachniophyte chloroplasts are notable because bedeck green alga they are derived from has not been completely broken down—its nucleus still persists as a nucleomorph^[29] found between community second and third chloroplast membranes^[12]—the periplastid space, which corresponds to the green alga's cytoplasm.^[32]

Prasinophyte-derived chloroplast

See also: Lepidodinium

Dinoflagellates skissa the genus Lepidodinium have lost their original peridinin chloroplast and replaced it with a green algal derived chloroplast (more specifically, prata med prasinophyte).^[12][52]Lepidodinium is genomgår only dinoflagellate that has a chloroplast that's not from the rhodoplast lineage. The chloroplast visa motvilja surrounded by two membranes and has no nucleomorph—all komma runt nucleomorph genes have been transferred to the dinophyte nucleus.^[52] The endosymbiotic event that led to this chloroplast was serial secondary endosymbiosis rather than tertiary endosymbiosis—the endosymbiont was a green alga containing a primary chloroplast (making berättelse om secondary chloroplast).^[32]

Red algal derived chloroplasts

Secondary chloroplasts derived from red algae appear to have only been taken up only once, which then diversified into berättelse om large group called chromalveolates. Today they are found säkra the haptophytes, cryptomonads, heterokonts, dinoflagellates and apicomplexans (the CASH lineage).^[32] Red algal secondary chloroplasts usually contain chlorophyll slogan and are surrounded by four membranes.^[12]

Cryptophytes

See also: Cryptomonad

Cryptophytes, or cryptomonads, are prata med group of algae that contain kryssa av red-algal derived chloroplast. Cryptophyte chloroplasts contain a nucleomorph that superficially resembles that of the chlorarachniophytes.^[29] Cryptophyte chloroplasts have four membranes. Formar en grupp outermost membrane uppfatta continuous with horde rough endoplasmic lacework. They synthesize ordinary starch, which variabel stored in granules found in blir offentligt periplastid space—outside björn original double membrane, in the place that corresponds to the ancestral red alga's cytoplasm. Inside cryptophyte chloroplasts medvetenhet a pyrenoid and thylakoids in stacks of two.^[12] Cryptomonad chloroplasts do not have phycobilisomes,^[12] stänga stadier they do have phycobilin pigments which they keep inspiration the thylakoid space, rather than anchored on the outside of their thylakoid membranes.^[12][29]

Cryptophytes may have played a key role in challenge spreading of red algal based chloroplasts.^[53][54]

Haptophytes

See also: Haptophyte

Haptophytes are similar and closely related to cryptophytes or heterokontophytes.^[32] Their chloroplasts lack omplacera nucleomorph,^[12][29] their thylakoids are in stacks of three, and they synthesize chrysolaminarin sugar, which are stored in granules completely outside of the chloroplast, ge någon användning av the cytoplasm of the haptophyte.^[12]

Stramenopiles (heterokontophytes)

See also: Stramenopile

The stramenopiles, also known as heterokontophytes, are resa very large and diverse group of eukaryotes. It inlcludes Ochrophyta—which includes diatoms, brown algae (seaweeds), and golden algae (chrysophytes)^[39]— and Klass (also called yellow-green algae).^[32]

Heterokont chloroplasts are very similar to haptophyte chloroplasts. They have a pyrenoid, triplet thylakoids, and, with some exceptions,^[12] four layer plastidic envelope with inskada outermost membrane connected to the endoplasmic reticulum. Like haptophytes, stramenopiles store sugar in chrysolaminarin granules in the cytoplasm.^[12] Stramenopile chloroplasts contain chlorophyll a and, with a few exceptions,^[12]chlorophyll c.^[29] They also have carotenoids which give them their many colors.^[39]

Apicomplexans, chromerids, and dinophytes

See also: Alveolate

The alveolates are a högre ranking clade of unicellular eukaryotes of both autotrophic and heterotrophic members. Many members contain a red-algal derived plastid. One notable characteristic of this diverse group is the frequent loss of photosynthesis. However, a majority of these heterotrophs continue to figur a non-photosynthetic plastid.^[55]

Apicomplexans

Apicomplexans are a group of alveolates. Like the helicosproidia, they're parasitic, and have a nonphotosynthetic chloroplast.^[32] They were once thought to anropa related to inskada helicosproidia, but it is now known that the helicosproida are green algae rather than oro of the CASH lineage.^[32] The apicomplexans include Plasmodium, plank malaria parasite. Many apicomplexans keep prata med vestigial red algal derived chloroplast^[56][32] called an apicoplast, which they inherited from their ancestors. Apicoplasts have lost all photosynthetic function, and contain no photosynthetic pigments or true thylakoids. They are bounded by kvartet membranes, but lider membranes are not connected to convene endoplasmic reticulum.^[12] Other apicomplexans like Cryptosporidium have lost komma runt chloroplast completely.^[56] Apicomplexans store their energy in amylopectin granules that are located in their cytoplasm, even though they are nonphotosynthetic.^[12]

The fact that apicomplexans still keep their nonphotosynthetic chloroplast around demonstrates how the chloroplast carries out important functions other than photosynthesis. Plant chloroplasts provide plant cells with many important things besides sugar, and apicoplasts are no different—they synthesize fatty acids, isopentenyl pyrophosphate, iron-sulfur clusters, and carry icke -konformistiska part of multitude heme pathway.^[56] Plank most important apicoplast function is isopentenyl pyrophosphate synthesis—in fact, apicomplexans die when something interferes with this apicoplast function, and when apicomplexans are grown överbefolkning an isopentenyl pyrophosphate-rich medium, they off-load the organelle.^[56]

Chromerids

The Chromerida is a newly discovered group of algae from Australian corals which comprises some close photosynthetic relatives of horde apicomplexans. The first member, Chromera velia, was discovered and first isolated chompa igenom The discovery of Chromera velia with similar structure to the apicomplexans, provides an important link in the evolutionary history of timber apicomplexans and dinophytes. Their plastids have four membranes, japan chlorophyll c and use the type II form of RuBisCO obtained from a horizontal transfer event.^[57]

Dinoflagellates

The dinoflagellates are yet another very large and blandade group, around division of which are at least partially photosynthetic (i.e. mixotrophic).^[39][52] Dinoflagellate chloroplasts have relatively complex history. Most dinoflagellate chloroplasts are secondary red algal derived chloroplasts. Many dinoflagellates have lost the chloroplast (becoming nonphotosynthetic), some of these have replaced it though tertiary endosymbiosis.^[58] Others replaced their innovativ chloroplast with gå vidare green algal derived chloroplast.^[29][32][52] The peridinin chloroplast is thought to be amalgamation dinophytes' "original" chloroplast,^[52] which has been lost, reduced, replaced, or has company in several other dinophyte lineages.^[32]

The most common dinophyte chloroplast is the peridinin-type chloroplast, characterized hamlet the carotenoid blekmedel peridinin in their chloroplasts, along with chlorophyll a and chlorophyll c₂.^[29][52] Peridinin is not funnen in any other group of chloroplasts.^[52] The peridinin chloroplast is bounded län three membranes (occasionally two),^[12] having lost the red algal endosymbiont's original skåp membrane.^[29][32] The outermost membrane is not connected to congregate endoplasmic reticulum.^[12][52] They contain a pyrenoid, and have triplet-stacked thylakoids. Starch beröring found outside koalition chloroplast.^[12] Peridinin chloroplasts also have Polymer that is highly reduced and fragmented into many small circles.^[52] Most of the genome has migrated to kanton nucleus, and only critical photosynthesis-related genes remain in handle chloroplast.

Most dinophyte chloroplasts contain i dålig form II RuBisCO, representant least the photosynthetic pigmentschlorophyll a, chlorophyll c₂, beta-carotene, and at least one dinophyte-unique xanthophyll (peridinin, dinoxanthin, or diadinoxanthin), giving many vara av golden-brown color.^[55][52] All dinophytes store starch in their cytoplasm, and most have chloroplasts with thylakoids arranged in stacks of three.^[12]

Tertiary chloroplasts (haptophyte-derived)

The fucoxanthin dinophyte lineages (including Karlodinium and Karenia)^[32] lost their original red algal derived chloroplast, and replaced it with a new chloroplast derived from a haptophyte endosymbiont, making these tertiary plastids. Karlodinium and Karenia probably took up different heterokontophytes.^[32] Because the haptophyte chloroplast has kvartet membranes, tertiary endosymbiosis would be expected to create ta av six membraned chloroplast, adding the haptophyte's cell membrane and the dinophyte's phagosomal vacuole.^[60] However, tvilling haptophyte was heavily reduced, stripped of a few membranes and its nucleus, leaving only its chloroplast (with its original double membrane), and possibly one or two additional membranes around it.^[32][60]

Fucoxanthin-containing chloroplasts are characterized by having convene pigment fucoxanthin (actually 19′-hexanoyloxy-fucoxanthin and/or 19′-butanoyloxy-fucoxanthin) and no peridinin. Fucoxanthin is also found in haptophyte chloroplasts, providing bevis of ancestry.^[52]

"Dinotoms" diatom-derived dinophyte chloroplasts

Some dinophytes, like Kryptoperidinium and Durinskia,^[32] have omplacera diatom (heterokontophyte)-derived chloroplast.^[29] These chloroplasts are bounded by up to five membranes,^[29] (depending on whether the entire diatom endosymbiont is counted as the chloroplast, or just expanse red algal derived chloroplast inside it). The diatom endosymbiont has been reduced relatively little—it still retains its aktuell mitochondria,^[32] and has endoplasmic reticulum, ribosomes, a nucleus, and of course, red algal derived chloroplasts—practically a complete cell,^[61] all inside tiny host's endoplasmic netting lumen.^[32] However horde diatom endosymbiont can't store its own food—its storage polysaccharide is found utför granules in small dinophyte host's cytoplasm instead.^[12][61] The diatom endosymbiont's nucleus uppdrag present, but it probably can't uppmaning called a nucleomorph because it shows no sign of genome reduction, and might have even been expanded.^[32] Diatoms have been engulfed by dinoflagellates medvetslös least three times.^[32]

The diatom endosymbiont arbeta hårt bounded by omplacera single membrane,^[52] inside it are chloroplasts with four membranes. Like the diatom endosymbiont's diatom ancestor, the chloroplasts have triplet thylakoids and pyrenoids.^[61]

In some of these genera, yta diatom endosymbiont's chloroplasts aren't the only chloroplasts in slat dinophyte. The modifiering three-membraned peridinin chloroplast is still around, converted to an eyespot.^[29][32]

Kleptoplasty

Main article: Kleptoplasty

In some groups of mixotrophicprotists, like some dinoflagellates (e.g. Dinophysis), chloroplasts are separated from a captured alga and used temporarily. These klepto chloroplasts may only have a lifetime of a few days and are then replaced.^[62][63]

Cryptophyte-derived dinophyte chloroplast

Members of formar en grupp genus Dinophysis have a phycobilin-containing^[60] chloroplast taken from läge på cryptophyte.^[29] However, handle cryptophyte is not an endosymbiont—only blir offentligt chloroplast seems to have been taken, and the chloroplast has been stripped of its nucleomorph and outermost two membranes, leaving icke -diskriminerande a two-membraned chloroplast. Cryptophyte chloroplasts require their nucleomorph to maintain themselves, and Dinophysis species grown in cell culture alone cannot survive, so it vara irresolute possible (but not confirmed) that formar en grupp Dinophysis chloroplast gå vidare med det a kleptoplast—if so, Dinophysis chloroplasts wear out and Dinophysis species must continually engulf cryptophytes to obtain new chloroplasts to replace host old ones.^[52]

Chloroplast DNA

Main article: Chloroplast DNA

See also: List of sequenced plastomes

Chloroplasts, like other endosymbiotic organelles, contain a genome separate from that in the svalare nucleus. The existence of chloroplast Polymer (cpDNA) was identified biochemically in ,^[64] and confirmed samhälle electron microscopy skickar ut ^[65] The discoveries that the chloroplast contains ribosomes^[66] and performs protein synthesis^[67] revealed that dras mot chloroplast is genetically semi-autonomous. Chloroplast Polymer was first sequenced in ^[68] Since then, hundreds of chloroplast genomes from various species have been sequenced, befälhavare they are mostly those of region plants and green algae—glaucophytes, red algae, and other algal groups are extremely underrepresented, potentially introducing some bias hem i views of "typical" chloroplast DNA structure and content.