HUMAN CELL

Human Cell

Human Cell

The human cell is a typical animal cell and is partitioned into two major components: protoplasm and nucleus enclosed within a cell membrane. Although different human cells have specific functional and structural characteristics, their basic structure is similar. The cell membrane is made up of lipids (phospholipids, gly—colipids, and steroids) and different membrane proteins (Fawcett, 2004). This paper discusses Why We study the Cell and Its Components.

The membrane proteins may be peripheral (attached to the peripheral parts of the cell membrane), transmembrane (communicates with the external and the internal environments) or lipid anchored (covalently bonded with the lipid molecules). Apart from giving shape to the cell the main functions of the cell membrane include: antigenic functions, containing of receptors and ion channels, participation in enzyme activity and maintaining a cell potential (Fawcett, 2004).

The nucleus, as described earlier, is a double membrane bound structure containing genetic information of the cell, which is encoded in the form of DNA. The protoplasm, with a gel—like consistency, harbors the different organelles of the cell: endoplasmic reticulum (ER), a system of membrane bounded channels with the main function of transportation of substances within the cell; 80 S ribosome, a subcellular entity usually associated with the ER and participates in protein synthesis; mitochondria, a double membrane bound structure carrying out respiratory functions in the cell; Golgi complex (GC), a system of vesicles that helps in transportation of different materials outside the cell; lysosome, membrane bound vesicles containing different enzymes like nucleases, phosphatases and proteases; and cen—trosomes and centrioles, cellular entities characteristic only for animal cells that participate in the process of cell division (Fawcett, 2004).

Other components of the human cell include the peroxysomes, different cytoplasmic inclusions, pigments (lipofuscin, lipochrome, etc.), microtubules and microfilaments (e.g., actin and myosin found in the human muscle cells), ...