Review Sheet for Test

Review Sheet for Test #1 Biology 2212 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
    Maintenance of Homeostasis

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

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

Energy -- Cell Energetics -- Energy Transformations
    Energy - capacity to do work
            States: kinetic (in action) or potential (stored)
            Types - radiant (light), electrical, mechanical, chemical, thermal (heat)
        Laws of Thermodynamics:
            First: Energy Finite (can=t be created or destroyed) but convertible
            Second: Every conversion increases entropy (some energy lost as heat)

MATTER -- Atoms: made up of subatomic particles:
             electrons (negative), protons (positive), neutrons (neutral)
        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 - "shared" 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 (see ions, below; to be charged 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); strongly polar bonds

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/NA
        structure; also important in keeping water liquid

Biologically important inorganic molecules -

H₂O: because of its polarity has high heat capacity, high heat of vaporization, good solvent, exhibits
capillarity (adhesiveness/cohesiveness), floats when solid. It is also an important reactant/product.

CO₂ & O₂

salts (ionic compounds)

Acids - proton (H⁺) donors & Bases - proton acceptors
Understand concept of pH

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):

alcohols: - OH
amine groups: - NH₂
carboxylic acids: - COOH

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

monosaccharides (glucose, fructose, deoxyribose, ribose); building blocks of . . .
disaccharides (sucrose)
polysaccharides (starch, glycogen)

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

neutral fats: building blocks -- glycerol and 3 fatty acids by dehydration synthesis; function as main
long-term energy storage molecule; also insulation

phospholipids: one end polar; main structural component of cell membranes

steroids: very different structure (4-ringed); most manufactured from cholesterol. Include steroid
hormones, vitamin D

carotenoids: plant pigments

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

primary -- Amino acid sequence
secondary and tertiary structure in essence determined by primary (A.A.sequence); secondary
structure due to hydrogen bonding between carboxyl/amine groups
Tertiary structure due to covalent/hydrogen bonding, charge differences, size differences, between
different R groups
quaternary -- more than one polypeptide chain "stuck together" to form functional protein; same
interactions as at tertiary level (but between R-groups of different chains)

structure determines function; may include additional extra components (co-factors, coenzymes, etc.)

Functions of proteins:

Structural proteins - typically secondary structural complexity only; form fibers or sheets; can have
secondary and quaternary structure with no tertiary structure (for example, collagen)
Functional proteins - tertiary or quaternary complexity; often soluble (in cytoplasm); includes
antibodies, some hormones, transport (eg., hemoglobin), and . . .

     Enzymes - organic catalysts for biochemical reactions
            Chemical Reactions: all reactions require some initial input of energy
            Types: synthesis - requires a net input of energy
                    degradation - liberates energy
                    exchange - energy balance depends on reactants (substrates) and products
                Endergonic/Exergonic reactions - Coupling of
                Free energy of the reaction
         Enzymes and Enzyme function: Virtually all reactions in the body require enzymes
            Do not change equilibrium of reactants (substrates) and products, or the free energy
            Do speed the rate of reactions (catalysts) by reducing the E_a (energy of activation)
            Active site
            Inhibitors - competitive/non-competitive; many enzymes inhibited by negative feedback

IV. Nucleic Acids

DNA - deoxyribonucleic Acid; hereditary material (in nucleus)
RNA - ribonucleic Acid; used in protein synthesis (produced in nucleus, used in cytoplasm

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

Nitrogenous bases:
purines (double-ringed): adenine and guanine
pyrimidines (single-ringed): cytosine, thymine (DNA), and uracil (RNA)

    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

MIXTURES: Solutions; Colloids (Sols and Gels); Suspensions

CELL STRUCTURE - cells are the fundamental units of life; cells are small because . . .?

Cell membrane - fluid mosaic model
      Components:
            Phospholipid bilayer, with cholesterol
           Extrinsic/intrinsic proteins
           Glycocalyx in animal cells (cell-cell recognition) -- "fuzzy coat" of glycolipids/
                    glycoproteins; each cell type unique
        Cell membrane is sempermeable (selectively/differentially permeable)
                  regulates movement of molecules into and out of cells
        hypo-/iso-/hypertonic solutions

Junctions: Tight, Gap, Desmosomes

Transport across the cell membrane:
        Passive processes: No energy expenditure required
                Diffusion -- Osmosis is a special case of a solvent (water) diffusing through a
                    semipermeable membrane
                Facilitated diffusion -- uses carrier proteins
        Active processes: Energy (ATP) required
                Active transport -- also uses carrier proteins; example: Na⁺ - K⁺ pump
                Endocytosis - bulk transport into the cell
                     Phagocytosis
                     Pinocytosis
                     Receptor-mediated pinocytosis
                Exocytosis - Bulk transport out of the cell

Cellular organelles - in the cytoplasm; KNOW STRUCTURES/FUNCTIONS of each

Mitochondria (doubled membrane)
Ribosomes
Endoplasmic Reticulum (ER) - smooth/rough
Golgi Apparatus
Lysosomes
Peroxisomes
Nucleus - contains nucleolus/chromosomes in porous double membrane
Cytoskeletal elements - microfilaments, intermediate filaments, microtubules
Centrioles/Centrosome
Cilia/Flagella