Review Sheet for Test #1
Biology 2212 Dr. James K. AdamsBiology
- Scientific study of lifeChemistry - Life processes dependent on Chemistry; study of Matter
and Energy
Energy
Polar does not equal 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 -
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
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, clotting, 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 Ea (energy of
activation)
Active
site
Activators and Inhibitors (competitive/non-competitive)
IV. Nucleic Acids
Functions: from DNA you make RNA, from RNA you make proteins, and the proteins make you
Nucleic acids are composed of nucleotide units - phosphate/5 carbon
sugar/nitrogenous base
phosphates and 5
carbon sugars make up 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
Cytoplasm/Cytosol -- with inclusions
Cellular organelles - in the cytoplasm; KNOW STRUCTURES/FUNCTIONS of each