Anatomy and Physiology Cell Structure
Structure selectively permeableCell (plasma) membrane - The selectively permeable outer boundary of a cell consisting of a phospholipids bilayer embedded with proteins. Nucleus - Cellular organelle that is enclosed by a double layer, porous membrane, and contains DNA. Cytoplasm - The entire contents inside of a cell excluding the cell membrane and nucleus. Cytosol - liquid portion
Cell Structure Shape differs according to cell function.
Cell Membrane Encloses the cell. Internal cell membrane forms membrane of nucleus and organelles. Composed mainly of phospholipids and protein. fluid mosaicDescribed as being a fluid mosaic model. Lipid layer
Lipid Layer Heads are made of phosphate groups and are considered hydrophilic = water loving. Tails are made of lipid molecules and are considered hydrophobic = water fearing.
Lipid Layer Proteins are embedded on and in the lipid layer. Some are attached to the surface, inner layer, and all the way through.
Function of the Cell Membrane Receives information from other cells. Transportation of molecules into and out of cells. Recognizes cells as belonging to a particular person. –Tissue typing for transplants.
Organelles Endoplasmic Reticulum –Network of tunnels throughout the cytoplasm of the cell. –Miniature circulatory system for the cell. 2 Types –Smooth (SER) Synthesizes lipids –Rough (RER) - has ribosomes Synthesizes proteins
Organelles Ribosomes –Function to make proteins for the cell. 2 Locations –Free floating in the cytoplasm. –Attached to endoplasmic reticulum.
Organelles Golgi Apparatus –AKA Golgi Body or Golgi Complex –Consists of tiny sacs stacked on top of one another. –Synthesizes large carbohydrates and combines with proteins=glycoprotein –Transport vesicles form, carrying substances to different parts of the cell.
Organelles Mitochondria –“Powerhouse of the cell” –Consists of a double membrane wall. –Inner membrane folds into extentions-cristae –This is the site of cellular respiration for production of ATP - cellular energy molecule.
Organelles Mitochondria continued… The more work a cell completes, the more mitochondria. –Ex. Muscle cells
Organelles Lysosomes –“Suicide bags or garbage disposals” –Contain enzymes that break down cell parts. –Destroy bacteria when it enters the body. White blood cells engulf bacteria and lysosomes destroy them.
Organelles Peroxisomes –Located in all human cells but most abundant in liver cells. –Among many functions, it helps in the detoxification of alcohol.
Organelles Centrioles –Appear as two dots located near the nucleus. –Forms spindle fibers during cell division (mitosis/meiosis).
Organelles Cell Fibers –Made of proteins Form a 3-D lattice which helps support the cell. (cytoskeleton) –Serves as the muscle of the cell. Ex.- microfilaments and microtubules.
Organelles Nucleus –Largest cell structure. –Contains DNA. –The center of the nucleus contains the nucleolus. Nucleolus manufactures ribosomes.
Inclusions Lifeless chemicals In a cell temporarily Store –Nutrients - glycogen and lipids –Pigments - ex. Melanin
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