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Biology notes-Chapter 2-The Chemistry of Life….
Name___________________________________
I. The nature of matterA. Atoms-________________________________________
 Derived from Greek word Atomos,which means “unable to be cut”
As described by _____________________,2300 years ago
 100 million atoms would make a room about 1 cm long
 DOES contain__________________particles that are smaller than an atom
Particle
Size
Location
Charge
th
electron
1/1840 of mass of
Energy levels in an
a proton(amu)
electron cloud
proton
1 amu
+
neutron
1 amu
nucleus
 Calculating subatomic particles:
PROTONS=Atomic Number=electrons(in a neutral atom)
MASS NUMBER=p + n
N=Mass-p
Electrons=p=atomic number

Since atoms tend to have p=electrons ,the + and – charge balance ,making them
neutral
 _________________center of atom bound by STRONG FORCES.
 Electrons are attracted to + nucleus ,but are held in levels by the energy of their
motion
B. Elements and Isotopes
 ____________________=PURE SUBSTANCE CONSISTING OF ONE KIND
OF ATOM
 More than 100 in existence but ~24 compose living things
 Represented by 1 or 2 letter symbol
 Common symbols:
Name
symbol Name
symbol
Hydrogen
Chlorine
Helium
Potassium
Lithium
Calcium
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Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
sodium
Arsenic
Bromine
Radon
Silver
Gold
Mercury
Tin
Iodine
Magnesium
Aluminum
Silicon
Barium
Radium
Uranium
Phosphorus
 Isotopes-atoms of the same element with a different number of neutrons---example:C-12,C-13,C-14----all averaged together for the atomic mass
 Isotopes are identified by ____________________.
 Radioactive Isotopes have unstable nuclei and break down at a constant rate
over time…
 Radioactive Isotopes
uses:__________________________________________________________
_____________________________ All isotopes of an element have the same chemical properties because they
have the same # of ______________-.
 ‘WEIGHTED MASS”-ie .Atomic weight=average mass of all isotopes for an
element

C. Chemical
Compounds=__________________________________________________________
____________
 Shown by a chemical formula
 Physical and chemical properties for an element differ a lot when they are
bound in a compound
 What is the ratio of H:O on H2O?____________________________
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
Physical
properties:______________________________________________________
____________________________
 Chemical
properties:______________________________________________________
___________________________
D. Chemical Bonds hold together atoms in a compound
1. Ionic Bonds-electrons are transferred from one to another creating an
electrical ,ionic charge that binds the atoms


2.




Tends to happen between metals and nonmetals
Looking @ p.37 ,draw what happens in a NaCl bond
Covalent Bonds-_____________________
The moving electrons of both atoms travel in the orbits of both atoms
Double or triple bonds occur when 4 or 6 electrons are shared
____________________-smallest unit of a compound
See drawing 2-4 on p.37 and draw the bond of H2O
E. Van der Waals Forces_intermolecular forces that result from
unequal sharing that results in tiny + or – charges in covalent bonds
 Help hold a molecule together a little more….see example of gecko on p.38
 Rapid movement of electrons can create regions of tiny (+) and (-) charges/As
some molecules are close together,slight attraction between oppositely
charged regions of nearby molecule-esp. when molecule is large

II. Properties of water
 Single most abundant compound in most living things
A. The Water Molecule
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 _____________-because of an uneven distribution of electrons between O
and H atoms
 O side is more – pole because it has more electrons
 It is ,essentially ,neutral ,but has a more – and more + end
 Because of this polarity water molecules can attract one another
 Polar charges are written in ( ) to show they are weaker than ionic charges
 H bonds not strong ,but water can form___________ H bonds…..causing
many of its properties/bonding with itself O,N, and F
 A single water molecule can be involved in as many as 4 H-bonds
 __________________-attraction between molecules of the same
substance…water is cohesive-example-surface tension allows spiders to
walk on water
 ___________________-attraction between molecules of different
substances-example-water creating meniscus as attaches to sides of
graduated cylinder
 H20 bonding in H2O is Unique orientation that enables expanding as
freezes
 HEAT CAPACITY---because of H-bonds ,takes a lot of heat to get water
molecules moving faster, creating high heat capacity….helping organisms
maintain body temp’s
 Look @ ppt and describe the effect of capillary action and how it is used
in
nature:______________________________________________________
____________________________________________________________
____________________________________________________________
_______________________________________
B.Solutions and Suspensions
 Water is often in a ________________________,where 2 or more
elements or compounds are PHYSICALLY combined
 2 types;
1) __________________mixture where components evenly
distributed
 Ions are surrounded by water molecules and evenly
distributed
 _____________-substance dissolved
 ______________-substance that does dissolving
2) ____________________-mixtures of water and non dissolved
materials—blood cells in a suspension of water in vessels
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B. Acids,Bases and pH Water molecule can react to form ions.Draw reaction as
shown @ bottom of p.42:
 _________________indicates concentration of H ions
in solution
Acid
BASE
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 Each step represents a power of 10-example-pH of 5
has 10 x as many H+ ions as same qty of ph 6
 ______________-higher concentrations of H+ ions
and pH <7
 _______________-alkaline-lower H+ concentration
and pH>7
 ________________weak acids or bases that react w/
strong ones to prevent sharp pH changes
 Buffers are dissolved in life’s fluids ,playing an
important role in maintaining homeostasis in
organisms
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III. Carbon Compounds
 In the 1800’s,chemists thought compounds
created by living things –organic compoundswere much different than others
 In 1838 a German chemist made the organic
compound,urea ,from nonorganic ammonium
cyanate…Thus principles of chemistry
governing nonliving could be applied to living
things
 _________________________is actually the
study of almost all C-compounds-many not
having anything to do w/ living things.
A. The Chemistry of Carbon
 Why is carbon special?---1) It has 4 valence
electrons and can make 4 bonds 2)It can bond w/
many other elements. Includes H,O,P,S,N to make
molecules of life
3)C can bond to other
C’s in single,double or triple bonds
4)C can form chains and
rings
methane
acetylene
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butadiene
benzene
isooctane
 Forms millions of different complex structures.
B. Macromolecules
 “Giant molecules found in organisms “
 Formed by _________________________________,in which large
compounds are built by joining smaller ones.
 ______________________-small units –join to form
__________________________-large molecules
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 The 4 groups of macromolecules
are______________________________________________________
__
C. Carbohydrates




Made up of C,H and O in ,uaually, a ratio 1:2:1.
Used by organisms for energy-main source.
Used for structure-by plants and some animals.
Break down of sugars,like glucose(C6H12O6)provides immediate
energy for cell activities
sucrose
 Starches are complex carbohydrates-stores extra energy
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CARB
MONOMER
 Single sugars are called ______________________,like
glucose,galactose and fructose.
 Sucrose=disaccharide-made of 2 sugars(notice structure in picture)
 ______________________________are large molecules formed
from monosaccharides
-such as glycogen or animal starch—glycogen from the liver helps out when
glucose levels run low.This is also stored in muscles for energy.
 Plants have plant starch and cellulose ,which gives plants their structure---major component of wood and paper.
D. Lipids
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 Large ,varied group of macromolecules that are generally are ________
in water
 Includes fats ,oils,waxes
 Made mostly of C,H and O
 Groups are ____________________.
 Can be used to store energy
 Some are parts of biological membranes or waterproof coverings
 Many are formed when glycerol is combined w/ fatty acids
1) If each C atom is joined to another C atom
by a single bond it is called
________________________.This is
because it has the max # of H-atoms.These
are________________.
2) If there is at least 1 C-C double bond ,it is
called
___________________________.These are
______________________@ room
temp.example-olive oil
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 If there is more than 1 C-C double
bond,it
is_____________________________
_____examples:oils such as
corn,sesame,canola and peanut
 Monomer basically glycerol and fatty
acids….see analyzing data,p.48
E. ____________________=macromolecules containing
C,H,O,N and P
 Polymers assembled from monomers
called________________________________
_, which contain 3 parts:
1. 5-C sugar
2. phosphate group
3. nitrogenous base
 Nucleic Acids store and transmit
______________or genetic info…2 types of
nucleic acids
1. _____________________________
_____-,involved in protein synthesis
and has the
sugar_________________.
2. Single strand
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RNA
3. _____________________________
______-contains genetic code and
has the sugar
____________________________.
DNA
 Double helix
 Contains deoxyribose
 For heredity
F. _________=macromolecules containing C,H,O and N
and composed of amino acids (monomer)
 _______________________ are compounds w/ an
amino group(-NH2) on one end and a carboxyl group(COOH) on the other end.
 Look @ Fig 2-17 on p. 48
basic amino acid formula
 More than 20 amino acids in nature
 All amino acids alike in region where they may be
joined by covalent bond.Thus any amino acid can be
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joined to any amino acid-by bonding an amino group
to a carboxyl group
 The portion of each amino acid that is different is the
side chain called a ____group.Some of these R groups
are acidic and some are basic…some polar and some
nonploar.Some have C rings .
 The instructions for assembling amino acids into
different proteins is stored in____.
 Each protein has a specific role….various functions
include:
1. control _____________rates(enzymes).
2. regulate cell processes .
3. forming bones and muscles
4. transporting substances into and out of cells
5. fighting diseases
 up to 4 levels of organization
1st –sequence of amino acids in a protein chain
2nd –amino acids within a chain can be twisted or
folded
3rd –chain itself is folded—If there is more than one
chain,each chain has a specific arrangement in
space.
4th –Van der Waals forces and H-bonds help
maintain a protein’s shape.
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IV. Chemical Reactions and Enzymes
A. Chemical
reactions=________________________________________________
_______________________________________________
Some are fast and some are slow
The elements entering into the reaction are
________________and that which is produced are the
________________________.
Co2 + H2OH2CO3 reaction that allows release of CO2 from the bloodstream
reactants
products
The above reaction is reversed in
the lungs.
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Chemical reactions always involve the breaking of bonds in
____________ and the formation of new bonds in
_____________.
B. Energy in Reactions
Energy is released or absorbed in chemical reactions.
1. Energy ChangesChemical Reactions that release energy are called
______________________ and often occur spontaneously.
Example: 2 H2 + O2 2 H2O….energy released as heat/sometimes as light and sound
Chemical reactions that require energy are
called_________________ and usually doesn’t occur by itself
Example: 2 H2O 2H2 + O2 requires an electrical current---NEEDS AN
ENERGY SOURCE
Organisms must have a source of energy to carry out necessary
reactions.Plants get this from products of
_____________________and animals get it from consuming
plants or other animals….thus from metabolizing food
2. Activation energy______________________________________________
______
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B. Enzymes________________________________________________________
A ______________ is a substance that speeds up the rate of a
chemical reaction by lowering activation energy.
Enzymes speed up reactions that take place in a cell
________________________speeds up the release of CO2 from
the bloodstream.
Enzymes are specific to the reaction they speed up and usually
named on the basis of the reaction.
C. Enzyme Action-
Reactants must collide w/ sufficient energy to make
_____________.
1. ENZYME-SUBSTRATE COMPLEX-enzymes provide a
site where reactants can be brought together to react,thus
reducing energy needed for the reaction.-made of proetein
Reactants of enzyme-catalyzed reactions are called
_____________________________.
Enzymes themselves unchanged in a reaction
Often end in –ase/sugars in -ose
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Substrates bind to a site on the enzyme called the
______________________________.These are
complementary shapes..These are bound together by
intermolecular forces making
an_______________________________These are
bound together until the reaction is done.
2. REGULATION OF ENZYME ACTIVITY
Affected by many variables,such as temperature ,pH
Cells can regulate enzymes in many ways—often w/ a protein
that turns the key enzymes on and off.
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