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For example, chloroplasts in plants and green algae have lost all phycobilisomes, the light harvesting complexes found in cyanobacteria, red algae and glaucophytes, but instead contain stroma and grana thylakoids. The glaucocystophycean plastid—in contrast to chloroplasts and rhodoplasts—is still surrounded by the remains of the ...
A chloroplast (/ ˈ k l ɔːr ə ˌ p l æ s t,-p l ɑː s t /) [1] [2] is a type of organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the energy from sunlight and convert it to chemical energy and release oxygen.
Chloroplasts have their own genome, which encodes a number of thylakoid proteins. However, during the course of plastid evolution from their cyanobacterial endosymbiotic ancestors, extensive gene transfer from the chloroplast genome to the cell nucleus took place. This results in the four major thylakoid protein complexes being encoded in part ...
The chloroplast is surrounded by 4 membranes: 2 layers resulting from the primary, and 2 resulting from the secondary. When the nucleus of the algal endosymbiont remains, it's called a "nucleomorph". [1] Most tertiary endosymbiosis events end up with only the plastid retained.
A diagram of a chloroplast. The TIC and TOC complexes are located on different sides of the chloroplast membrane.. The TIC and TOC complexes are translocons located in the chloroplast of a eukaryotic cell, that is, protein complexes that facilitate the transfer of proteins in and out through the chloroplast's membrane.
As an example, a yeast vacuole is normally acidified by proton transporters on the membrane. A third role is to establish specific locations or cellular addresses for which processes should occur. For example, a transcription factor may be directed to a nucleus, where it can promote transcription of certain genes. In terms of protein synthesis ...
Chloroplasts probably evolved following an endosymbiotic event between an ancestral, photosynthetic cyanobacterium and an early eukaryotic phagotroph. [17] This event (termed primary endosymbiosis) is at the origin of the red and green algae (including the land plants or Embryophytes which emerged within them) and the glaucophytes, which together make up the oldest evolutionary lineages of ...
The chloroplasts are pigmented similarly to those of the heterokonts, [5] but the structure of the rest of the cell is different, so it may be that they are a separate line whose chloroplasts are derived from similar red algal endosymbionts. Haptophyte chloroplasts contain chlorophylls a, c 1, and c 2 but lack chlorophyll b.