Animal - Animal Cells

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Animal cells are typical of the eukaryotic cell, enclosed by a plasma membrane and containing a membrane-bound nucleus and organelles. Unlike the eukaryotic cells of plants and fungi, animal cells do not have a cell wall. This feature was lost in the distant past by the single-celled organisms that gave rise to the kingdom Animalia. Most cells, both animal and plant, range in size between 1 and 100 micrometers and are thus visible only with the aid of a microscope.
The animal kingdom is unique among eukaryotic organisms because most animal tissues are bound together in an extracellular matrix by a triple helix of protein known as collagen. Plant and fungal cells are bound together in tissues or aggregations by other molecules, such as pectin. The fact that no other organisms utilize collagen in this manner is one of the indications that all animals arose from a common unicellular ancestor. Bones, shells, spicules, and other hardened structures are formed when the collagen-containing extracellular matrix between animal cells becomes calcified.Animals are a large and incredibly diverse group of organisms.
Centrioles: Centrioles are self-replicating organelles made up of nine bundles of microtubules and are found only in animal cells.
Cilia and Flagella: For single-celled eukaryotes, cilia and flagella are essential for the locomotion of individual organisms.
Endoplasmic Reticulum:The endoplasmic reticulum is a network of sacs that manufactures, processes, and transports chemical compounds for use inside and outside of the cell.
Endosomes and Endocytosis:Endosomes are membrane-bound vesicles, formed via a complex family of processes collectively known as endocytosis, and found in the cytoplasm of virtually every animal cell.
Golgi Apparatus:The Golgi apparatus is the distribution and shipping department for the cell's chemical products.
Nucleus: The nucleus is a highly specialized organelle that serves as the information processing and administrative center of the cell.