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During the development/ differentiation of proplastids to chloroplasts—and when plastids are differentiating from one type to another—nucleoids change in morphology, size, and location within the organelle. The remodelling of plastid nucleoids is believed to occur by modifications to the abundance of and the composition of nucleoid proteins.
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.
Within the envelope membranes, in the region called the stroma, there is a system of interconnecting flattened membrane compartments, called the thylakoids.The thylakoid membrane is quite similar in lipid composition to the inner envelope membrane, containing 78% galactolipids, 15.5% phospholipids and 6.5% sulfolipids in spinach chloroplasts. [3]
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 ...
Chloroplasts can be seen travelling around the central vacuole of a cell in Rhizomnium punctatum Cytoplasmic streaming in onion epidermal cell. Cytoplasmic streaming, also called protoplasmic streaming and cyclosis, is the flow of the cytoplasm inside the cell, driven by forces from the cytoskeleton. [1]
Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...
The morphological similarity between chloroplasts and cyanobacteria was first reported by German botanist Andreas Franz Wilhelm Schimper in the 19th century [197] Chloroplasts are only found in plants and algae, [198] thus paving the way for Russian biologist Konstantin Mereschkowski to suggest in 1905 the symbiogenic origin of the plastid. [199]
Along with red algae [1] and cyanobacteria, they harvest light via phycobilisomes, structures consisting largely of phycobiliproteins. The green algae and land plants have lost that pigment. [ 11 ] Like red algae, and in contrast to green algae and plants, glaucophytes store fixed carbon in the cytosol .