BioChemistry

BioChemistry

1. Plasma Membrane

   • Structure and Function
     • Components in Cell Membrane: phospholipid bilayer, Integral proteins, Peripheral proteins, Glycoproteins, Glycolipids, Cholesterol
     • The cell membrane is selectively permeable to ions and organic molecules and controls what substances can pass in and out of cells. The basic function of the cell membrane is to protect the cell from its surroundings.
     • Passive Transport: Movement of substances in water, Solution = solute dissolved in solvent
       • Diffusion: movement of a substance through a cell membrane. The movement is from an area of high concentration to an area of low concentration of that substance = along a concentration gradient, movement stops when concentration of substance is equal in both areas = equilibrium
       • Osmosis: diffusion of water through cell membrane. The movement of water from an area with a high concentration of water to an area with a low concentration of water, movement stops when concentration of water reaches equilibrium
       • Facilitated Diffusion:movement of big lipid insoluble molecules through cell membrane using transport proteins (integral), movement from an area of high concentration to area of low concentration, movement stops at equilibrium, no energy required
     • Active Transport: Moves solutes against concentration gradient or from high to low concentration. Uses energy from ATP or from breaking down ATP
       • Sodium Potassium Pump: Active transport of sodium and potassium ions across the cell membrane against their concentration gradients
       • Vesicles: Big molecules that can’t pass cell membrane or transport proteins embedded in cell membrane
         • Endocytosis: Cell membrane pinch around molecules to be transported into cell
         • Receptor-mediated Endocytosis: Receptor proteins on surface of cell membrane bind with molecules to be transported into the cell, then endocytosi
         • Exocytosis: molecules in a vesicle to be transported out of cell fuse with cell membrane and exit
   • Organelles
     • Any of a number of organized or specialized structures within a living cell.

2. Energy Dynamics

   • Thermodynamics
     • First Law: States that energy can't be created or destroyed, but can only undergo conversion from one form to another; thus, the amount of energy in the universe is unchangeable.
     • Second Law; A statement concerning the transformation of potential energy to heat; it says that disorder is continually increasing in the universe as energy changes occur, so disorder is more likely than order
   • Enzymes
     • Metabolism is all the chemical reactions that occur in a cell to keep an organism alive. Cells use enzymes to lower the energy required for a reaction to occur.
     • Enzymes are special proteins that speed up or catalyze a reaction. A catalyze is a substance that will speed up the chemical reaction without being consumed. Enzymes can also be reused over again.
     • A substrate is the reactant that an enzyme acts on when it catalyses a reaction. The substrate will bind to the active site with a specific shape (must fit perfectly) and create products from the substrate.
     • Induced-Fit Model: a substrate binds to the active site, the enzyme changes shape to accommodate the substrate
     • Controlling Enzyme Function: Enzyme inhibitors (competitive and noncompetitive), Allosteric regulation, feedback inhibition, enzyme production and location.
     • Factors that Affect Enzymes: Cofactors, Coenzymes, Competitive and noncompetitive inhibitors, regulation (activator and inhibitor), Temperature and pH

3. Macromolecules

   • Functional Groups: A group of atoms responsible for the characteristic reactions of a particular compound.
     • Ex. Carbonyl, Carboxyl, Hydroxyl, Amino, Phosphate and Sulfhyrl
   • Reactions
     • Excergonic : This refers to a reaction where energy is released. The reactants lose energy; Gibbs free energy is negative under constant temperature and pressure. Usually does not require energy and occurs spontaneously .
       • Hydrolysis: Breaking bonds down to release energy
     • Endergonic: the chemical reaction in which the standard change in free energy is postive and energy is absorbed
       • Dehydration Synthesis: Making bonds in order to store energy
   • Lipids: any of a class of organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents. They include many natural oils, waxes, and steroids.
   • Carbohydrates: any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.
   • Nucleic Acids: a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain
   • Proteins: any of a class of nitrogenous organic compounds that consist of large molecules composed of one or more long chains of amino acids and are an essential part of all living organisms, especially as structural components of body tissues such as muscle, hair, collagen, etc., and as enzymes and antibodies.