what is plastids
The plastid is a major double-membrane organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids were discovered by anton van Leeuwenhoek.The term"plastids"was coined by Ernst Haeckal.Plastids are the site of manufacture and storage of important chemical compounds used by the cell. They often contain pigments used in photosynthesis, and the types of pigments present can change or determine the cell's color. They have a common evolutionary origin and possess a double-stranded DNA molecule that is circular, like that of prokaryotic cells.
In plants, plastids may differentiate into several forms, depending upon which function they play in the cell. Undifferentiated plastids (proplastids) may develop into any of the following variants:[3]
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Chloroplasts green plastids: for photosynthesis; see also etioplasts, the predecessors of chloroplasts
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Chromoplasts coloured plastids: for pigment synthesis and storage
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Gerontoplasts: control the dismantling of the photosynthetic apparatus during plant senescence
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Leucoplasts colourless plastids: for monoterpene synthesis; leucoplasts sometimes differentiate into more specialized plastids:
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Amyloplasts: for starch storage and detecting gravity (for geotropism)
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Elaioplasts: for storing fat
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Proteinoplasts: for storing and modifying protein
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Tannosomes: for synthesizing and producing tannins and polyphenols
The plastid is a major double-membrane organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids were discovered by anton van Leeuwenhoek.The term"plastids"was coined by Ernst Haeckal.Plastids are the site of manufacture and storage of important chemical compounds used by the cell. They often contain pigments used in photosynthesis, and the types of pigments present can change or determine the cell's color. They have a common evolutionary origin and possess a double-stranded DNA molecule that is circular, like that of prokaryotic cells.
In plants, plastids may differentiate into several forms, depending upon which function they play in the cell. Undifferentiated plastids (proplastids) may develop into any of the following variants:[3]
-
Chloroplasts green plastids: for photosynthesis; see also etioplasts, the predecessors of chloroplasts
-
Chromoplasts coloured plastids: for pigment synthesis and storage
-
Gerontoplasts: control the dismantling of the photosynthetic apparatus during plant senescence
-
Leucoplasts colourless plastids: for monoterpene synthesis; leucoplasts sometimes differentiate into more specialized plastids:
-
Amyloplasts: for starch storage and detecting gravity (for geotropism)
-
Elaioplasts: for storing fat
-
Proteinoplasts: for storing and modifying protein
-
Tannosomes: for synthesizing and producing tannins and polyphenols
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