E.r., The Golgi Body And

Part I of Essay
Thousands of structures with membranes crowd the eukaryotic cytoplasm, the most numerous being called the endoplasmic reticulum (ER), a dense network of membranes running through the cytoplasm of every cell and enclosing a network of interconnected tubes (cisternae), which ....

Part II of Essay
.... ER usually form a tightly packed and flattened sac-like structures, that form inter-connected compartments within the cytoplasm. The internal space formed by the membrane sheets is known as the ER lumen. In most cells the ER lumen forms a single internal compartment. The membranes of other organelles are not connected to the ER and appear to form separate distinct compartments within the cytoplasm. The ER membranes and lumen contain a large number and variety of enzymes which catalyse many different types of chemical reactions. In some cases ....