Cell Structure. Melanie Pd. 8. Cells are the building blocks of all plants and animals. Cells are produced by the division of preexisting cells. Cells are the smallest units that perform all vital physiological functions. Each cell maintains homeostasis at the cellular level. Cell Theory.
All parts of the cell must work together to maintain homeostasis at the tissue, organ, and system levels.
Cell Membrane- Lipid bilayer, containing phospholipids, steroids, and proteins. Isolation, protection, sensitivity, organization.
Nucleus- Nucleoplasm containing nucleotides, enzymes, and nucleoproteins; surrounded by double membrane or “nuclear envelope”
Cells obtain 95% of their necessary energy from a Membranous Organelle inside the cell named, Mitochondria.
The cell-division cycle is a essential process where a single-celled organism splits to make another organism.
Many cell functions that involve the cell membrane, such as secretion or ciliary movement, involve changes in the transmembrane potential.
Two factors, one passive and one active, maintain the transmembrane potential.
Most cells in the body attach to other cells or to extracellular protein fibers.
In Gap junction, two cells are held together by an interlocking of membrane proteins.
At tight junctions there is a partial fusion of the lipid portions of the two cell membranes.
At intermediate junctions the opposite cell membrane are held together by a thick layer of proteoglycans.
At desmosomes these is a very thin proteoglycan layer between the opposing cell membranes, reinforced by a network of intermediate filaments that lock the two cells together.
Cytosol or intracellular fluid- contains dissolved nutrients, ions, soluble and soluble proteins and waste products.
Cytoskeleton- is an internal protein framework that gives the cytoplasm strength and flexibility.
Centriole- is a cylindrical structure composed of short microtubules.