Chloroplast
The chloroplast crushed a spheroid; have a shape. I call internal space surrounded with a double film (Outer Membrane and Inner Membrane) stroma (Stroma). I showed a stroma with the lightest green. The chlorophyl is put in the discal vacuole called thylakoid (Thylakoid) drawn a lot in a figure and the thylakoid piles up and is gathered up in a lump called granum (Granum). Some thylakoid spreads into long pieces and link the plural grana. I call this lamella (Lamella). Hydrogen-ion concentration of thylakoid membrane inside namely lumen (Lumen) rises by photosynthesis. ATP synthetase distributed on the thylakoid membrane using hydrogen ion concentration gradient composes the ATP which is the energy source of the cell from ADP.
The chloroplast (ようりょくたい British: Chloroplast) is an organelle of the photosynthesizing half autonomy; [1]. I transcribe it into the chloroplastic strike in katakana.
Table of contents
General statement
It is an organelle seen in phototroph and is a kind of プラスチド. Because I include yellow carotenoid and a large quantity of chlorophyll, I generally see it in green [1]. But I see it in crimson because the red algae include a phycobilin pigment in brown because the chloroplast of brown algae has fucoxanthin other than chlorophyll [1].
I include one spherical chloroplast per one cell with the algae that the cell system is low like primitive brown algae [1]. When it becomes red algae, brown algae, the frog spit, I come to include a big chloroplast of various form including a cup form, a star form, the volution, board form one - approximately several [1]. When this becomes more multicellular frog spit and the land plant, it will be included approximately 10 normal - several hundred per one cell [1].
As for the size and shape, around 5-10μm thickness is convex lens form of around 2-3μm a diameter with most of metaphyte [1]. Refer to a figure of publication for the internal structure.
General characteristic
Because I include photosynthesis pigments such as chlorophyll (chlorophyl), there is a clear color and is the organelle which is easy to confirm even living body observation most.
In the case of vascular plant, the chloroplast exists as a plastid with the non-photosynthesis cell. The plastid has amyloplast, a kind of waterweed plastic strike, various kinds including the leucoplast, but all plastids are surrounded in a double indusium, and it features it to have chloroplast DNA.
The chloroplastic form varies by taxa, but variety is generally high in an alga. As for the thing of the higher plant, most are slightly flat; is discal. In the alga, a thing of various form is known. The most famous one will enter the cylindrical cell with a ribbon type seen in a spirogyra in a spiral. Besides, a thing of various form including a thing of star-shaped ホシミドロ and the thing of サヤミドロ to become into a board form, and to always turn aspects to toward the light is known.
In the case of a seed plant, the chloroplastic form is simple; is discal. It often seems that I equal the circumference of the cell when I see the size with around 5μm in diameter, a microscope. This is because a vacuole occupies the central part of the cell. It is seen to move by protoplasmic streaming.
As for the chloroplast of the seed plant, the outside is covered by a double film, and the inside part is called a stroma. In the stroma, the light bag-formed structure made of a large number of films forms a line. I call this bag thylakoid. The structure that large number of small thylakoid piled up calls this a granum in many places.
Original DNA (chloroplast DNA, cpDNA) is included in a stroma, and I cope with it, and original ribosome is included here. The enzyme about the reaction about photosynthesis pigment and photosynthetic light is located in the thylakoid membrane.
Work
Photosynthesis is the best known main function, but plays key role that, in addition, nitrogen metabolism, the metabolism in the plant cell including amino acid composition, lipid composition, the pigment composition are important.
Having original genomic DNA and ribosome, it is thought that it comes from that I let eubacteria and the eukaryote which a common ancestor of the truth nuclear phototroph photosynthesizes live together in a cell. Refer to the following "origin" for this.
Chloroplast DNA forms a nucleoid body with various protein, and, like the chromosome of the nucleus, as for the nucleoid body, it is a unit of a reproduction, transcription, the distribution of chloroplast DNA. But there is not the histone. In addition, there is not the protein such as HU, DPS known as a bacterial DNA binding protein to the chloroplast of the green plant basically. Sulfite reductase functions as a DNA binding protein instead.
Plastidial origin
Of the oxygen occurring cyanobacterium same for the symbiont which is the plastidial origin it is thought sort of, but do not still know it whether which of the cyanobacterium of the actual money is near, or come from the close species of those ancestors class. By the way, for the origin of the cyanobacterium, helio bacteria and クロロフレクサス are considered as the thing which it supplied photosystem 1 and 2 to, but a function of the constitution protein except that is related systematically does not just cope because real photosystem 1.2 and the photosystem of these photosynthetic bacterias are considerably different. In addition, I do not understand the function except the photosynthesis in the origin of the cell.
Because the chloroplast cannot function without the product of the nucleus gene, I cannot culture the chloroplast thought about in old days. However, there is the example of the sea slug as the evidence that can function even if a chloroplast is in condition to have separated from a cell. The sac tongues of the friend of the sea slug eat to breathe in the material in the cell of the seaweed, but, in a certain kind, an example to take in a cell is known without dismantling an algal chloroplast. The chloroplast taken in by an animal cell photosynthesizes here, and it is said that it supplies the product to an animal cell in this way.
Algal chloroplast
Like statement above, chloroplastic forms and essence are various in the alga. The photosynthesis pigment has different things depending on a group, too. A relatively common form and essence includes structure called the pyrenoid. It is said that I participate though I change a photosynthetic product into stored substance in protein characteristics with round granular structure to be 1-several in a plastid. Starch composition is carried out in the Chlorophyceae here.
There is a point covered with a film often with more than of algal chloroplast three folds at the point that is greatly different from a thing of the plant kingdom in an alga. In addition, chloroplastic DNA may look like a clear lump. In late years these came to be regarded as a thing by the symbiosis in the overlap-like cell. Therefore it is thought that "the original nucleus alga such as the cyanobacterium lived together to the eukaryote which does not have a chloroplast as for the thing having plant kingdom and two folds of algal film chloroplasts with the origin". It is easy to understand the double film that the inside thinks that the outside comes from the cell membrane of the plant cell a cell membrane of the original nucleus phototroph. But the conclusive evidence is not provided [2].
In contrast, there is the nucleus of structure which, for example, the chloroplast of the black LARA country on algae be wrapped up in a fourfold film, and is said to be ヌクレオモルフ among comedians with a handsome man from the outside. Two folds of inside films are original chloroplasts, and, as for the outside film, the algal cell membrane which owned it, the most outer stratum come from a cell membrane of this alga in itself in this respect [3]. In other words, I can judge it because a non-photosynthesis-related eukaryote took in a truth nuclear alga in a cell when I made it an alga [4]. ヌクレオモルフ is an algal nuclear vestige taken in. In the case of this alga, it is taken as Chlorophyceae that it was busy [3].
Source
References
- "Iwanami biology dictionary fourth edition" Iwanami Shoten, 1996. ISBN 4-00-080087-6。
- Mitsuo Chihara editing, Kunio Iwatsuki, the Shunsuke Mawatari supervision with "algal variety system" kimono Hanafusa, 1999. ISBN 978-4-7853-5826-6。
This article is taken from the Japanese Wikipedia Chloroplast
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