Chapter 2: Part 2

       The second part of the chapter continues to go into depth on chemistry. There are several other key aspects of chemistry that are important when learning about anatomy and physiology. First, let us go over what polar and nonpolar covalent bonds mean. Nonpolar covalent bonds have electrons that are shared equally.  This produces electron balance, which means that no side of the molecule is charged. An example of a nonpolar molecule is CO2. Polar covalent bonds are when the electrons are shared unequally, which means the atoms in the bond can have different charges. This creates something called a dipole. A dipole means one side of the molecules electronegative and the other side is electropositive.  An example of a polar molecule is water, H2O. Polar and nonpolar molecules are important in anatomy and physiology when learning about different parts of the cell.

      A great example of how polar and nonpolar molecules work is the cell membrane. When looking at a cell membrane up close it has a bilayer, two layer, and membrane. This membrane is made up of phospholipids which have a polar and nonpolar side.  The inside of the bilayer is nonpolar and the outsides are polar. This is important for the cell because it allows cells to work well with water in the cell and outside of the cell. Molecules need to pass through the cell membrane in order to feed the cell and also get things out of the cell.

The second thing I am going to discuss is different reactions.

Synthesis Reactions           A+B-àAB

• ·         Taking small molecules and making them big
• ·         anabolic reaction
• ·         always involved bond formation

Decomposition reactions   ABà A+B

• ·         breaking down a molecule into smaller molecules
• ·         catabolic reaction
• ·         reverse of synthesis

Exchange reactions           AB+ CàAC + B

• ·         AKA displacement reaction
• ·         Involving both synthesis and decomposition
• ·         Example: ATP transfers its terminal phosphate group to glucose

Oxidation reactions

• ·         AKA Redox reactions
• ·         Food fuels are broke down for energy
• ·         Involve exchange reaction between reactants
• ·         If the products added a Hydrogen is it called a Reduction
• ·         If the products gave a Hydrogen it is oxidize

     A mnemonic device I use to remember which reaction is reduction or oxidation is

           LEO SAYS GER

    Lose an electron= oxidized

    Gain an electron= Reduction

Tune in next week for Chapter 3 review!

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