1 21 15 Lecture 4 Body Organization Fluid Compartments 3 o Plasma Interstitial Fluid Intracellular Fluid o Barrier between fluids Capillary wall between plasma and IF Cell Membrane between IF and IF o These 2 barriers limit movement Subcellular Composition Ions have a charge aka electrolytes o Net positive cation or negative anion charge Free Radicals single electron in outer orbital o The single electron is unstable and does not want to be alone There is an odd number of electrons lacks a pair of electrons o Free Radicals remove electrons from another molecule This is called oxidizing o Our body makes free radicals when we are sick They are effective at fighting pathogens but they also damage our good cells too For that reason they are said to be indiscriminant We don t want free radicals when we are healthy though o Need to be neutralized by donors ex vitamin A and D Can neutralize free radicals without turning into one AKA antioxidants neutralize free radicals by donating an We don t want these when we are sick only when we are electron healthy o Examples Know these Super Oxide Nitric Oxide Hydroxyl Radical O NO OH Molecular Bonds o Figure 2 5 o Covalent sharing of electrons very strong bond But not always sharing equally ex H O Creates partial charge Terminology based on water and oil lipids fat 1 21 15 Polar Hydrophilic Lipophobic vs vs vs Nonpolar Hydrophobic Lipophilic Figure 2 8 Some compounds are amphipathic o Have polar and nonpolar part ex phospholipid o Like dissolves like o So they dissolve in o Noncovalent bonds Ionic electrical attraction of opposite charges Ex salts figure 2 4 Na Cl NaCl Between metals and nonmetals Strong without water so weak in body Hydrogen Bonding interaction with H bound Hydrophobic Bonding avoiding polar Weak Weak Plasma Membrane Functions o Regulates movement in out within figure 3 8 o Binds chemical messengers o Holds cell in extracellular matrix o Allows for cell s shape and motility Components in fluid mosaic form o Things move relative to each other o Made up of more than just one component o 1 Phospholipid main building block Polar head and 2 nonpolar tails amphipathic Spontaneously form bilayer o 2 Cholesterol Amphipathic small polar head induces correct orientation Form vesicles move things in and out of the cell o 3 Proteins 2 categories Integral Within the plasma membrane Serve as channels receptors and anchors extracellular matrix Peripheral On the side of the plasma membrane Impact shape and motility of the membrane 1 21 15
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