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 -

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 in many different reactions in the body

O₂

(& CO₂)

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, cellulose, chitin)

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 B 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 B more than one polypeptide chain Astuck together@ to form functional
protein; same interactions as at tertiary level (but between R-groups of different chains)

structure determines function; may include additional conjugated groups

Functions of proteins:

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

Enzymes - organic catalysts for biochemical reactions

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

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

mitochondria (doubled membrane)
plastids -- chromoplasts, leukoplasts, and chloroplasts (chlorophyll; doubled membrane)
Ribosomes
Endoplasmic Reticulum (ER) - smooth/rough
Golgi Apparatus
Lysosomes
(Microbodies - peroxisomes, glyoxysomes, etc.)
Vacuoles
Nucleus - contains nucleolus/chromosomes in porous double membrane
Cytoskeletal elements - microfilaments, intermediate filaments, microtubules
Centrioles/Basal bodies
Cilia/Flagella