Internal Structures of a Plant Cell

·         The Nucleus
§  Spherical body containing a nucleolus
§  Surrounded by the nuclear membrane
§  Contains DNA (genetic material in chromosomes)

·         Nucleolus
§  An organelle within the nucleus where ribosomal RNA is produced
§  It controls many of the functions of the cell (by controlling protein synthesis)

·         Centrosome
§  It is a small body located near the nucleus that forms and organizes microtubules
§  Microtubules are important in cell division (mitosis)

·         Ribosomes
§  Are small organelles composed of RNA-rich cytoplasmic granules that are sites of protein synthesis

·         Endoplasmic Reticulum
§  Endoplasmic reticulum is a system of interconnected, membranous, infolded and convoluted sacks located in cytoplasm (the ER is continuous with the outer nuclear membrane)
§  It transports materials through the cell and produces proteins
§  Smooth Endoplasmic Reticulum are smooth (i.e. no ribosomes on surface)

§  Contains enzymes and produces and digests lipids (fats) and membrane proteins

·         Golgi Complex: (i.e. Golgi apparatus or Golgi body)
§  Is a flattened, layered, sac-like organelle that looks like a stack of pancakes, located near the nucleus
§  It packages and transports materials (proteins and carbohydrates) to different locations inside/outside cell
·         Mitochondria
§  Spherical to rod-shaped organelles with a double membrane that generates energy for the cell
·         Plastids
§  Are structures responsible for photosynthesis, storage of products like starch and for the synthesis of many classes of molecules such as fatty acids etc. needed as cellular building blocks and/or for the function of the plant. There several types; proplastids, etioplasts, chloroplasts, chromoplasts, leucoplasts and leucoplasts specialized for different functions in the plant body.
·         Vacuoles
§  Are regions bound by membrane and filled with cell sap and surrounded by the tonoplast
§  In mature living cells may compose 90 – 95% of cell volume
§  Storagesite for variety of (ergastic) substances such as:
§  Water
§  Enzymes and other proteins
§  Water-soluble pigments (e.g. red and blue anthocyanins)
§  Toxic alkaloids, tannins
§  Lipids 
§  Crystals (calcium oxalate, calcium carbonate, silicon dioxide)
§  Organic acids (oxalate, malate)

Macro Photography of Bubble Coral

References
Evans, W. C. (2009). Trease and Evans Pharmacognosy. India: Reed Elsevier Limited.

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