chapter 2, worksheet A

Chapter 2: The Chemical Level of Organization Directions: The following is an outline of chapter 2. As you read all of chapter 2, fill in the blanks of the outline. Answer any numbered questions. Draw the structures when instructions tell you so. Matter: Atoms and Molecules Atoms •    Smallest unit of an element •    Subatomic particles are made of •   ______________: (+) charge •   ______________: neutral •   ______________: (-) charge Structure of an atom •    Nucleus is made of _____________ and _____________ •    Electron Shell Structure of atom •    Atomic number •   Equals number of _______________ •    Atomic mass •   Equals _____________ + _______________ •    Isotopes of element •   Reflects number of _________________ •    Atomic weight •   Averages _______________ abundances Structure of atom •    Electrons surround _______________ •    Electrons organized in shells (layers) •    The _____________ shell determines chemical properties Draw atoms of carbon and neon with their electron shells (as fig. 2-3). Notice that the first shell can only hole 2 electrons but the second shell can hold up to 8 electrons. Atoms are most stable when their outer electron shell is full.       Why do you think hydrogen likes to form a single bond with other atoms but carbon likes to form 4 bonds with other atoms?         Key Note     All matter is composed of atoms in various combinations. Their interactions establish the foundations of physiology at the cellular level. Chemical Bonds and Compounds •    Atoms bond in chemical reactions •    Reactions transfer electrons •    Electrons are gained, lost, or shared •    Molecules or compounds result •   Compounds contain several _______________   Ionic Bonds •    Atoms gain or lose electrons •    Charged atoms are ions •    Ions bear (+) or (-) charge •   ______________ have (+) charge •   ______________ have (-) charge •    Cations and anions attract •    Ions form bonds (example: Sodium chloride crystal) Draw sodium and chloride ions with their electron shells (fig 2-4). What are other common ions in our body fluids?   Covalent bonds •    Some atoms share electrons •    Shared electrons complete outer shell •    Sharing atoms bond covalently •   Single covalent bond •   One shared _______________ •   Double covalent bond •   ________ shared electrons Draw the structure of an oxygen molecule (fig 2-5) showing the electron shells and the shared electrons.       How many bonds are there between the Oxygen atoms?   Nonpolar and Polar Covalent Bonds •    Equal electron sharing •   _______________ covalent bonds •   Example: carbon-carbon bonds •    Non-equal electron sharing •   ___________ covalent bonds •   Example: oxygen-hydrogen bonds     Hydrogen bonds •    Weak attractive force •    Between two neighboring atoms •   A polar-bonded hydrogen, and •   A polar-bonded oxygen or nitrogen •    For example, between water molecules Draw polar water molecules (fig. 2-6)       Explain why water molecules have a tendency to stick together.     Chemical Reactions Metabolism      All  the chemical reactions in the body •    Consumes r______________ •    Produces p______________ •    Breaks or makes chemical bonds between atoms Basic Energy Concepts •    Work—______________ or ______________ in matter's physical structure •   E.g., running, synthesis •    Energy—ability to do ________ •    Potential energy—____________ energy •    Kinetic energy—energy of _________________   Describe or illustrate examples of potential and kinetic energy.           3 types of reactions Decomposition—breaks molecule into smaller pieces •    In chemical notation: •   AB ® A + B •   Releases covalent bond energy •    Hydrolysis—Decomposition reaction with H•OH •   E.g., food digestion •    Catabolism—Sum of all the body's decomposition reactions   Synthesis Reactions •    In chemical notation: •   A + B ® AB •   Absorbs _____________ •     Formation of new bonds •    Dehydration synthesis •   Removal of H•OH between molecules •    Anabolism—Sum of the body's  synthesis reactions   Exchange—shuffles pieces between molecules •    In chemical notation: •   AB + CD ® AC + BD •    Decomposition and synthesis   Reversible Reactions •    A + B « AB •    Equilibrium—Condition when the f____________ and r______________ reactions occur at the same rate   Key Note      When energy is exchanged, heat is produced. Heat raises local temperatures, but cells cannot capture it or use it to perform work.   Enzymes and Reactions Activation Energy      Quantity of energy needed to start a chemical reaction •    Catalysts r__________ activation energy to speed reaction •    Enzymes c___________ cellular reactions   Exergonic—Reactions that r______________ energy •    E.g., decomposition reactions Endergonic—Reactions that c________________ energy •    E.g., synthesis reactions   Draw a picture illustrating how an enzyme catalyzes a reaction (see fig 2-7).