Plastids

Plastids

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  Plastids PRAKASH DHAKAL M. Sc.Public Health Microbiology Tribhuvan University, Nepal
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  Plastids  Plastids aredouble membrane organelle which are found in the cells of plants and algae.  They are responsible for manufacturing and storing of food.  They often contain pigments used in photosynthesis and the types of pigments that determine the cell’s color. Types of plastids  Plastids are of several forms, depending upon which function they play in the cell. Chloroplasts Chromoplasts Gerontoplasts Leucoplasts Amyloplasts Proteinoplasts Elaioplasts Plastids
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  1) Chloroplasts (chloro=green;plast=living):  They are green plastids. It contains chlorophyll pigments. It is found in higher plants and green algae. Plant cells with chloroplasts
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  2) Chromoplasts (chromo=color;plast=living):  These are colored plastids They contain various pigments.  They contain yellow, orange and or red pigments.  Chromoplasts are found commonly in flowers and fruits. 3) Gerontoplasts (geronto= old age, plast= living):  It is found in formerly green tissues that are currently senescing (Plant senescence is the process of aging in plants).
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  4) Leucoplasts (Leuco=white;plast=living):  These are the non-pigmented organelles which are colorless.  They are usually found in most of the non-photosynthetic parts of the plant like roots.  They acts as a storage sheds for starches, lipids, and proteins depending on the needs of plant.  Leucoplasts are of three types: a) Amyloplasts : Stores starch b) Proteinoplasts : Proteinoplasts helps in storing the proteins that a plant needs and can be typically found in seeds. c) Elaioplasts : Elaioplasts helps in storing fats and oils that are needed by the plant.
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  Leucoplasts in plantcells
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  Etioplasts are chloroplaststhat have not been exposed to light. They are usually found in flowering plants (Angiosperms) grown in the dark. If a plant is kept out of light for several days, its normal chloroplasts will actually convert into etioplasts. Etioplasts lack active pigment and can technically be considered leucoplasts. High concentrations of etioplasts will cause leaves to appear yellow rather than green. ALSO REMEMBER