ANIMAL CELLS: Animal cells are eukaryotic cells, or cells with a membrane-bound nucleus. Unlike prokaryotic cells, DNA in animal cells is housed within the nucleus. In addition to having a nucleus, animal cells also contain other membrane-bound organelles, or tiny cellular structures, that carry out specific functions necessary for normal cellular operation. Organelles have a wide range of responsibilities that include everything from producing hormones and enzymes to providing energy for animal cells. Animal cells are similar to plant cells in that they are both eukaryotic cells and have similar organelles. Animal cells are generally smaller than plant cells. While animal cells come in various sizes and tend to have irregular shapes, plant cells are more similar in size and are typically rectangular or cube shaped. A plant cell also contains structures not found in an animal cell. Some of these include a cell wall, a large vacuole, and plastids. Plastids, such as chloroplasts, assist in storing and harvesting needed substances for the plant. Animal cells also contain structures such as centrioles, lysosomes, cilia, and flagella that are not typically found in plant cells. Animal Cells: Structures and Organelles The following are examples of structures and organelles that can be found in typical animal cells: Centrioles – organize the assembly of microtubules during cell division. Cytoplasm – gel-like substance within the cell. Endoplasmic Reticulum – extensive network of membranes composed of both regions with ribosomes (rough ER) and regions without ribosomes (smooth ER). Golgi Complex – responsible for manufacturing, storing and shipping certain cellular products. Lysosomes – sacs of enzymes that digest cellular macromolecules such as nucleic acids. Microtubules – hollow rods that function primarily to help support and shape the cell. Mitochondria – power producers and the sites of cellular respiration. Nucleus – membrane bound structure that contains the cell’s hereditary information. Nucleolus – structure within the nucleus that helps in the synthesis of ribosomes. Nucleopore – tiny hole within the nuclear membrane that allows nucleic acids and proteins to move into and out of the nucleus. Ribosomes – consisting of RNA and proteins, ribosomes are responsible for protein assembly. Animal cells contain other cell structures that are not depicted in the illustration above. Some of these structures include the cytoskeleton, cilia and flagella and peroxisomes.
Posted on: Tue, 15 Oct 2013 04:43:02 +0000