Endomembrane system is an important system to synthesize and delivery proteins to their target location either inside or outside the cells.

a. what is the endomembrane system made of? is it found in prokaryotic cells, eukaryotic cells or both?
b. describe how an extracellular enzyme secreted by fungus cell is made, transported and targeted to the outside of the cell by the endomembrane system and across cell membrane transport.

A. Endomembrane system is involved in the production of proteins and how they are transported into membranes, organelles or out of the cell. They are also involved in metabolism and transportation of of lipids; and neutralising poisonous substances. Membranes are connected either through physical continuity or through vesicles (i.e. sacs made of membranes). Thus, endomembrane system consists of nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacoules and plasma membranes. Endomembrane system is not found in prokayotic organisms.

B. After enzyme has been coded for in the nucleus and successfully transcribed in the nucleus; and translated in the cytoplasm, the enzyme will be transferred from endoplasmic reticulum to golgi apparatus, where it is modified and packaged to exit the cell membrane for desired destination.

Explanation:

a) Endomembrane system: is a set of membranes that form functional structures that are compartmentalized in the cytoplasm. These formed structures, known as organelles, either directly or indirectly interact for transport of molecules inside and outside the cell.

It is made of: plasma membrane, nuclear membrane, vacuoles, vesicles, lysosomes, endoplasmic reticulumn and endosomes. This is in Eukaryotes.

In some prokaryotes like photosynthetic bacteria, the plasma membrane is highly folded forming layers that gather light. In green sulfur bacteria the light-gathering membranes fold to form structures called chromosomes.

b) The enzyme will be synthesized by the ribosomes, transported to the lumen of the rough endoplasmic reticulumn (ER) for further processing or posttranslational modification. Thereafter, COPII coated vesicles will traffic the enzyme from the ER to the Golgi-apparatus for maturation. Vesicle formation will transport the matured enzyme to the plasma membrane and exported extracellularly by exsosomes and microvesicles.  

stress fractures occur largely in the feet and legs and are common in sports that require repetitive impact, primarily running/jumping sports such as gymnastics or track and field.

amber has allowed scientists to study dna that has been preserved over millions of years.