Chemistry in Biology
Chp. 6-HB,B1 & part of B2
I.
Atoms, elements and compounds
MATTER ______________________________________________________________
A.
Atoms (building blocks of matter)
1.
a.
Size = billions make a period on piece of paper
b.
Subatomic particles
~PROTON-____________
-found in the center of the atom (nucleus)
~NEUTRONS-______________
-found in the center of the atom (nucleus)
~ELECTRONS –
-found outside of nucleus
-moves around center in energy levels (clouds)
c.
-electrons=proton number
d. structure of atom based on attraction between protons
and electrons.
e. Nucleus (p + n)
B.
Elements
1.
Defined-pure substance that cannot be broken down into other substances
by physical or chemical means.
2.
3.
Over 100 elements, 92 naturally occurring
4.
Classified based on number of protons/electrons
5.
6. Periodic table of elements p. 149
a.
Periods-horizontal rows
b.
Groups-similar chemical & physical properties
c.
d.Metals, metalloid, nonmetal, recently found, gas, liquid, solid, synthetic
p. 149
6.
Isotopes
a.
~ex. C-12
C-14
b.
Does NOT change the overall charge of an atom
7.
Radioactive isotopes are __________________________________
a.
Used to help diagnose disease & locate some cancers
b.
Changing neutrons affects the stability of the nucleus
~sometimes decays or breaks apart (releases radiation)
c.
~rate of decay predictable, thus one can calculate the age of an
object by finding how much C-14 remains.
C.
1.
2.
D.
Caused when 2 or more elements combine (H20)
Chemical formula
a.
b.
How many atoms?
c.
Ex. NaCl, C6H12O6,
~fuel=hydrocarbons
~
3.
Compounds made by using specific kinds of elements in a fixed ratio
Ex. H20
4.
Compounds have different characteristics than elements that they create
Ex.
H=gas
O=gas
5.
Compounds CANNOT be broken down to individual elements by physical
means. (tearing or crushing)
Ex.
H2O electrolysis & changes to H+ & O2
Chemical Bonds (covalent & ionic bonds)
1.
Introduction
a.
b.
Elecrons (ONLY) involved in bonding
~1st level holds max 2 electrons
~
~3rd level holds max 18 electrons
c.
Partially filled outer energy (electron) levels not as stable as empty
or filled levels
~elements become more stable by losing or gaining electrons to fill
their outer levels.
~this forms chemical bonds (sharing or getting rid of electrons)
d.
Forming chemical bonds locks energy (stores energy) food to fat
e.
Ex. Food to energy for running
2.
Covalent bonds
a.
b.
Both elements benefit by filling their outer energy levels by sharing
partially filled electron energy levels.
c.
Ex. H2O p. 152
d.
Most compounds in living things are covalent
e.
Covalent bond compounds called MOLECULES
f.
Depending on he number of shared electrons it may have single bond,
double bone, triple bonds p. 153
g.
NONPOLAR =
POLAR=
3.
Ionic bonds
a.
GIVES UP or ACCEPTS electrons to fill outer level to become stable
b.
c.
d.
e.
f.
g.
h.
ION =
Ex. Na+
ClEx. NaCl p. 153
Ionic bond is an electrical attraction between 2 oppositely charged
atoms
Helps to maintain homeostasis in living things
~travels in/out cells
~transmits signals (nerves) senses
Metals donate electrons
Nonmetals usually receive electrons
Most dissolve in water forming loose ions which causes an electrical
current
i.
~ionic cmpds solid at room temp.
~ionic liquids don’t evaporate & safe to hold
j.
k.
Solvents (cleaners) are ionic
~don’t evaporate
~safe to handle & able to be recycled
E.
1.
2.
3.
4.
5.
6.
II.
Attractions between molecules as electrons share
Larger molecules attract stronger
Not strong as covalent & ionic bonds
a.
Ex. Gecko’s climbing fig. 12
b.
Ex. Water is sticky & forms droplets
Force which keeps H2O molecules together
Chemical reactions allow living things to grow, develop, reproduce, and adapt.
A.
1.
Introduction
a.
Chemical reactions defined (chemical change)
~a process by which atoms or groups of atoms in substances
are reorganized into different substances
~ex.
~evidence of change-heat, light, new gas, liquid or solid
formed.
b.
~substances may change appearance but not chemically
changed
~ex. H2O
1.
Reactants
~
B.
2.
Products
~right side of equation
REACTANTS-----------------PRODUCTS
C6H12O6 + O2--------------CO2 + H2O
3.
a.
b.
c.
Matter cannot be created nor destroyed (Law of the
conservation of mass)
Equations MUST show the balance of mass
Reactant mass = Product mass
Atom mass = atom mass
Coefficient =
~used to make number of atoms equal
~Number of atoms found by multiplying coefficient with
subscript number of each element
C6H12O6 + O2-------CO2 + H20
C6H12O6 + 6O2------6CO2 + 6H2)
K + B2O3--------------K2O + B
6K + B2O3------------3K2O + 2B
C.
1.
Ex. Choco chip cookies
Reactants (need energy to start) = Products (cookies)
2.
a.
STARTS chemical rxn’s
b.
Minimum amount of energy
Ex. Lighting a candle-candle burns on its own once activated.
3.
a.
Energy high to activate
b.
If energy of product LESS than reactants it is an
EXOTHERMIC reactions ex. Candle
c.
If energy of product MORE than reactant energy it is an
ENDOTHERMIC reaction. Ex. Bomb
D.
1.
Introduction
a.
All Living things are chemical factories driven by chemical
reactions.
b.
Activation energy in living things (to start a reaction) needs
to be less so as not to harm cells.
2.
a.
Defined- a catalyst is a substance that loers the activation
energy needed to start a chemical reaction.
b.
c.
Does NOT get used up in the reaction.
3.
Enzymes (lock & key model)
a.
Biological catalysts fig. 17 p. 159
b.
c.
Not used up in a reaction and can be used again
d.
Name of enzyme describes what it does
Ex. Lipase works on lipids
e.
Most enzymes specific to one reaction
f.
SUBSTRATE-reactants that bind to an enzyme
g.
ACTIVE SITE-location on enzyme where substrate binds
H2 + O -------------H2O
-active site changes shape briefly to release product
h.
Factors which affect enzyme activity
~
~temp. (ours work at 98.6F)
~presence of other substances
i.
Ex. Of enzymes at work
~
~bite by insect, reptile, etc
~ripening of fruit
j.
Anabolic rxn-build up
k.
Enzymes are the chemical workers of the cell.
III.
Water and solutions
The properties of water make it well suited to help maintain homeostasis in an organism
A.
1.
Polar molecules-molecules with an uneven distribution of charges
(attraction)
2.
a.
More attraction to O than H
b.
Mickey Mouse appearance to molecule
3.
a.
Having two opposite poles or ends.
Ex. Magnents
b.
Attraction-weak electrostatic attraction.
Ex. H+ bond
4.
a.
H weak interaction with Fl, O, N
b.
Strong type of VanderWaal’s force
c.
d.
Polar reacts with Polar molecules
5.
Nonpolar molecules have no charge & do NOT react with each other
Ex. Water + oil
B.
1.
Mixture-combination of 2 or more substances in which each
substance remains the SAME.
2.
3.
a.
Defined-uniform throughout
ex. Tea!
b.
Heterogeneous mixture
a.
Parts of mixture remain intact & distinct
b.
Ex.
c.
Suspension-most of these particles settle out of a solution
over time.
d.
Colloidal solution-is heterogeneous but doesn’t settle out of
solution
Ex. Blood, fog, smoke, butter, mayo, milk, paint, ink, etc.
4.
a.
b.
c.
Acids
~substances which release H+ when dissolved in water
Bases (alkaline)
~substances which release (OH-) hydroxide ions when
dissolved in water
Acids & bases are very important in the function of an
organism
5.
a.
b.
c.
d.
amount of H+ & OH- ions determines the strength of an acid
or base
pH scale
~1-14
~Acids
~Bases 7.0001-14
pH 6.5-7.5 most common in living things
~maintain homeostasis by controlling H+ ions
Ex.
Buffers
~mixtures which react to keep pH in a particular range
~
IV. The building blocks of life
REVIEW IONIC & COVALENT BONDING
Organisms are made of C-based molecules
A.
1.
Life on Earth is C-based
2.
3.
Carbon
C-12
a.
4 electrons in outermost energy level
b.
c.
B.
Enables C to bond with each other
~shapes=chains, branched chains, rings fig. 25
~
Macromolecules (4 kinds)
1.
Defined-large molecules of Carbon molecules
2.
Polymers p. 167
a.
Repeating units of identical (or almost identical) compoundsmonomers
*3.
a. made of CHO written as (CH2O)
~n=number of CH2O repeating units
b.
1:2:1 ratio C6H12O6 (base) (glucose)
c.
Simple sugars (monosaccharides)
~
~n=3 to 7
d.
Disaccharide
~2 monosaccharides
~
~C12H24O12
~ex. Sucrose/lactose
e.
~ex. Potato
~ex. Glycogen (stored glucose)-energy for life
f.
Roles of carbohydrates
~
~plant structure (cellulose fibers)
~chitin (animal carbohydrates that makes exoskeletons
~cell walls of fungus
*4.
a. made of CHO but not in 1:2:1 ratio like carbohydrates
b.
c. made of fatty acids, glycerol & others
d.
Primary function for energy storage
e.
~solid at room temperature
f.
Oil
~liquid at room temperature
g.
h. Saturated & unsaturated fats
~lipids essential for life
~structure shows fatty acid tails p. 168
~each tail made of CH chains & held together by single or
double bonds
~SATURATED FATS have all single bonds. No more available
spots for H+ to bond
~UNSATURATED FATS
have at least one double bond
so the fat can be broken
~POLYUNSATURATED FATS have many double bonds and is
more easily broken
i.Phospholipids (Phosphorus + lipid)
~responsible for structure & function of the cell membrane
~lipid tails are hydrophobic-water repels
~serves as water barriers
j. Steroids
(cholesterol & hormones)
~helps to make Vit. D, estrogen & testosterone.
*5.
a. made of C-chains with HON
(CHON) + S
-all A.A. have the same basic structures
b. amino acid structure
-central carbon (4 free bonds)
-1 bond with Amino group
-NH2
-1 bond with carboxyl groups
-COOH
-1 bond with variable group
~20 different variable groups = 20 different
amino acids
c.
-peptide bonds join amino acid together to make a
protein
ex. Making brownies
-peptide bonds forms one amino acid group &____________
e.
3-dimensional protein structure p. 170
-based on variable groups, proteins can have 4 different
levels of structure
~1st level=number &
~2nd level= it folds into a helix , folds or pleat p. 170 (3-d)
~3rd structure (tertiary) is globular or fibrous
*6.
a.
b.
c.
store & transmit genetic information
made of repeating units of CHON & Phosphorus
6 major nucleotides made of phosphate, nitrogenous bases
(ATCG) & sugar
d.
~DNA has deoxyribose sugar
~