Endoplasmic reticulum definition

The cell organellae in woody plants are the nucleus, mitochondrion, rough-endoplasmic reticulum (r-ER), smooth endoplasmic reticulum (s-ER), Golgi-body, plastid, vacuole, microbody, etc. Their functions are very complicated, and some have definite roles in the biosynthesis of cell-wall components. Hence, changes in size of cell organellae are likely to occur, since cell-wall composition depends upon the stage of wall development. 

Enantiotopic atoms or groups 479 Endergonic reactions 286 Endo ring conformation 212 Endocytosis 13,425-427 Endoderm 23 Endoglucanases 602 Endoglycanases 593, 602 Endonexin SeeAnnexin Endoplasmic reticulum (ER) 10,13,14, 521 cisternae of 14 definition of 14 in micrograph 13 rough 14 smooth 14 Endosomes 13, 426 Endosperm 30... 

Fig. 7.11. Comparison of the fine structure of the membranes of the eggs of Hymenolepis diminuta and H. nana. Note in H. nana (in contrast to H. diminuta) (a) the embryophore is thin and incomplete - a feature which may facilitate hatching in the gut of the definitive host (b) there is an additional polar filament layer between the oncospheral membrane and the basal lamina. Gc, Golgi complex ger, granular endoplasmic reticulum /, lipid bodies m, mitochondria n, nucleus v, vacuoles. (After Fairweather Threadgold, 1981a Holmes Fairweather, 1982.)...

Because an organelle is defined as a portion of a cell enclosed by a membrane, ribosomes are not, strictly speaking, organelles. Smooth endoplasmic reticulum does not have ribosomes attached, and ribosomes also occur free in the cytosol. The definition of organelle also affects discussion of the cell membrane, cytosol, and cytoskeleton. 

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