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Over time, many parts of the chloroplast genome were transferred to the nuclear genome of the host, [71] [72] [88] a process called endosymbiotic gene transfer. As a result, the chloroplast genome is heavily reduced compared to that of free-living cyanobacteria.
Like mitochondria, chloroplasts have a double-membrane envelope, called the chloroplast envelope, but unlike mitochondria, chloroplasts also have internal membrane structures called thylakoids. Furthermore, one or two additional membranes may enclose chloroplasts in organisms that underwent secondary endosymbiosis , such as the euglenids and ...
Chloroplast thylakoids frequently form stacks of disks referred to as grana (singular: granum). Grana are connected by intergranal or stromal thylakoids, which join granum stacks together as a single functional compartment. In thylakoid membranes, chlorophyll pigments are found in packets called quantasomes. Each quantasome contains 230 to 250 ...
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 ...
This membrane contains an enzyme called NAD(P)H dehydrogenase which transfers electrons in a linear chain to oxygen molecules. [1] This electron transport chain (ETC) within the chloroplast also interacts with those in the mitochondria where respiration takes place. [2] Photosynthesis is also a process that Chlororespiration interacts with. [2]
Stroma, in botany, refers to the colorless fluid surrounding the grana within the chloroplast. [1]Within the stroma are grana (stacks of thylakoid), the sub-organelles where photosynthesis is started [2] before the chemical changes are completed in the stroma.
Each photosystem has two parts: a reaction center, where the photochemistry occurs, and an antenna complex, which surrounds the reaction center. The antenna complex contains hundreds of chlorophyll molecules which funnel the excitation energy to the center of the photosystem. At the reaction center, the energy will be trapped and transferred to ...
In cell biology, it is most commonly described as the region between the inner membrane and the outer membrane of a mitochondrion or a chloroplast. It also refers to the space between the inner and outer nuclear membranes of the nuclear envelope , but is often called the perinuclear space.