Review Sheet for Test #1        Biology 1107            Dr. James K. Adams

Biology - Scientific study of life

    Characteristics of life B Composed of cells; Maintenance of boundaries (cell membranes/
sheets of cells); metabolism; reproduction; growth/development/maintenance; movement  
in response to stimuli

Scientific Method

Unifying Concept of Biology:   Evolution through natural selection - works on variation

Hierarchical Organization of Life: Atoms/Molecules, Organelles/Cells, Tissues, Organs, 
    Organ Systems, Organism, Population, Community, Ecosystem, Biosphere/Ecosphere

Chemistry - study of Matter and Energy; Life processes dependent on Chemistry

Atoms: made up of subatomic particles - electrons (negative charge), protons (positive
            charge), neutrons (neutral); nucleus contains protons and neutrons
   
     Atomic number (proton #)
   
     Atomic mass/weight (protons + neutrons)
    Electrons - move; have energy
   
     orbitals (can hold a pair of electrons)
   
     electron shells
   
     valence electrons - # of e-=s in outer shell; determine chemical properties of atoms

Chemical bonds - Ashared@ pair of electrons -- formation of molecules/compounds
   
     electronegativity - strength of attraction of an atom for electrons
    Covalent bonds:
        non-polar - e-=s shared equally (atoms involved equally electronegative); strongest  
            bonds in solution
      
  polar - e->s shared unequally, charge difference across bond (atoms involved not  
             equally electronegative)

    Polar Charged (to be charged [ions], atoms/molecules must have
                different numbers of electrons and protons, not simply an uneven distribution)
    
    Ionic bonds - involves ions
         one strongly electronegative atom "takes" electrons from weakly electronegative atoms; 
              results in ions negative anions and positive cations
      
   charges attract each other (hold ions together)

Important concept in understanding polarity: "Like dissolves like" - polar substances (eg., 
    water) dissolve other polar substances, non-polar substances (eg., lipids) dissolve other 
    non-polar substances

    Hydrogen bonds - weak; unequally "shared" proton; though weak, still important in  
        protein/nucleic acid structure; also important in keeping water liquid

Biologically important inorganic molecules -

Although presented here as inorganic, there are organic salts and organic acids and bases

Classes of organic molecules - contain carbon (C)/rich in energy (lots of bonds)
   
     All have hydrogen (H), most also have oxygen (O) and nitrogen (N)

Hydrocarbons: Understand the concept of isomers (same chemical formula, different 
    chemical structure)
Carbon-Carbon bonding - single, double, triple; ring structures
Saturation
Functional groups
: (Others also important (phosphate, sulfhydryl) but must be able to 
    draw the following):

Dehydration syntheses (condensation) / Hydrolysis
     used in synthesizing/breaking down polysaccharides, neutral/phospholipids, proteins, 
        nucleic acids

I. Carbohydrates - (C(H2O))n; end in -ose and/or begin with glyc-; KNOW FUNCTIONS

II. Lipids - fats and oils; essentially non-polar; KNOW FUNCTIONS

III. Proteins - structurally and functionally most varied group of organic molecules
        Amino Acids (A.A.=s) - basic building blocks of proteins; 20 different types
        Peptide bonds (formed by dehydration synthesis) -- Proteins are essentially polypeptides

Structural levels of proteins - primary, secondary, tertiary, quaternary

structure determines function; may include additional conjugated groups

Functions of proteins:

              Enzymes - organic catalysts for biochemical reactions

IV. Nucleic Acids

    composed of nucleotide units - phosphate/5 carbon sugar/nitrogenous base
   
phosphates and 5 carbon sugars make of the backbone

Nitrogenous bases:

DNA - double helix; backbone with deoxyribose sugar
   
     cytosine = guanine; adenine = thymine (= and = represent # of hydrogen bonds)

RNA - single stranded; ribose sugar; uracil instead of thymine

ATP - (adenosine triphosphate) - (RNA) adenine nucleotide with two more phosphates
   
     high energy phosphate-phosphate bonds body=s ready source of energy


CELL STRUCTURE
- cells are the fundamental units of life;
cells are small because . . .?
        cellular organelles - in the cytoplasm (of eukaryotic cells);
            KNOW STRUCTURES/FUNCTIONS
of each