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HomeReadSign inNEUROSCIENCE: CANADIAN 1ST EDITION OPEN TEXTBOOKCONTENTSSearch…1.1 The Cellular Levels of OrganizationIntroductionFluorescence-stained Cell Undergoing MitosisFigure 1.A lung cell from a newt, commonly studied for its similarity to human lung cells, is stained withfluorescent dyes. The green stain reveals mitotic spindles, red is the cell membrane and part of the cytoplasm,Next SectionIncrease Font Size
and the structures that appear light blue are chromosomes. This cell is in anaphase of mitosis. (credit:“Mortadelo2005”/Wikimedia Commons)After studying this chapter, you will be able to:Describe the structure and function of the cell membrane, including its regulation of materials into and out of the cellDescribe the functions of the various cytoplasmic organellesExplain the structure and contents of the nucleus, as well as the process of DNA replicationExplain the process by which a cell builds proteins using the DNA codeList the stages of the cell cycle in order, including the steps of cell division in somatic cellsDiscuss how a cell differentiates and becomes more specializedList the morphological and physiological characteristics of some representative cell types in the human bodyYou developed from a single fertilized egg cell into the complex organism containing trillions of cells that you see when you look in amirror. During this developmental process, early, undifferentiated cells differentiate and become specialized in their structure andfunction. These different cell types form specialized tissues that work in concert to perform all of the functions necessary for the livingorganism. Cellular and developmental biologists study how the continued division of a single cell leads to such complexity anddifferentiation.Consider the difference between a structural cell in the skin and a nerve cell. A structural skin cell may be shaped like a flat plate(squamous) and live only for a short time before it is shed and replaced. Packed tightly into rows and sheets, the squamous skin cellsprovide a protective barrier for the cells and tissues that lie beneath. A nerve cell, on the other hand, may be shaped something like astar, sending out long processes up to a meter in length and may live for the entire lifetime of the organism. With their long windingappendages, nerve cells can communicate with one another and with other types of body cells and send rapid signals that inform theorganism about its environment and allow it to interact with that environment. These differences illustrate one very important theme thatis consistent at all organizational levels of biology: the form of a structure is optimally suited to perform particular functions assigned tothat structure. Keep this theme in mind as you tour the inside of a cell and are introduced to the various types of cells in the body.