The major route for endocytosis in most cells, and the best-understood, is that mediated by the molecule clathrin. This large protein assists in the formation of a coated pit on the inner surface of the plasma membrane of the cell.This pit then buds into the cell to form a coated vesicle in the cytoplasm of the cell.he major route for endocytosis in most cells, and the best-understood, is that mediated by the molecule clathrin. This large protein assists in the formation of a coated pit on the inner surface of the plasma membrane of the cell.
Sponges are extremely primitive invertebrate life so are classed under the Kingdom Animalia, they do not photosynthesise so are not plants. They are also very different to fungi and have an entirely different composition and life cycle. A sponge if passed through a sieve gradually reforms its original shape.ponges are extremely primitive invertebrate life so are classed under the Kingdom Animalia, they do not photosynthesise so are not plants. They are also very different to fungi and have an entirely different composition and life cycle. A sponge if passed through a sieve gradually reforms its original shape.
Sponges do not have any internal organs or a nervous system. Their skeleton is made of tiny, needle-like splinters, or a mesh of protein called spongin (2) Most of the Demospongiae are made of spongin. Some of the sponges are made of both spicules and spongin.Bath sponges are made of calcereous or siliceous spicules, and they are therefore soft to the touch.he sticky collars also pick up tiny particles of food and bacteria brought in by the water (2). Unlike the cells of most other animals, the cells of sponges do not form into various organs like kidney, liver, or nerves. Sponge cells are totipotent (Dawkins 2004).