Download BiolChapter 2

Biology Chapter 2
The Chemistry of Life
I. The nature of matterA. Atoms-_____________
Derived from Greek word Atomos,which means
“unable to be cut”
As described by _____________________,2300 years
ago
Basic unit of matter
Democritus
Atoms cont’d
100 million atoms would make a
room about 1 cm long
DOES
contain__________________particles
that are smaller than an atom
subatomic
Subatomic particles
particle
size
location
electron
1/1840th mass Energy
of a
levels in an
amu(proton)
electron
proton
1 amu
cloud
nucleus
neutron
1amu
nucleus
charge
-
+
none
Calculating subatomic particles:
PROTONS=Atomic
Number=electrons(in a neutral atom)
MASS NUMBER=p + n
N=Mass-p
Electrons=p=atomic number
Examples:
For Cl –atomic # =17 and mass =35
P=17,electrons=17,neutrons =35-17=18
For Li---It has 3 protons and 4 neutrons
Li has mass number=7 ,atomic # =3 and
electrons= 3
Atoms cont’d
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
nucleus
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
Element
Common symbols
name
hydrogen
helium
lithium
boron
carbon
nitrogen
oxygen
sym
bol
H
He
Li
B
C
N
O
name
symbol
Fluorine
neon
sodium
magnesium
aluminum
Silicon
Chlorine
F
Ne
Na
Mg
Al
Si
Cl
Common symbols
name
potassium
calcium
arsenic
bromine
radon
silver
gold
symbol
K
Ca
As
Br
Rn
Ag
Au
name
mercury
tin
iodine
barium
radium
phosphorus
Uranium
symbol
Hg
Sn
I
Ba
Ra
P
U
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
______________-.
Mass
number
Tracers-esp. in medical
diagnosis,dating
fossils,identifying and
treating cancer,kill
bacteria
electrons
Isotopes cont’d
‘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?_________
Substance formed by 2 or
more substances in definite
proportions
2:1
Physical
properties:______________________
Chemical properties:_______________
Don’t change
substance—
color,smell..
Change substanceflammability
,corrosion
D. Chemical Bonds hold together
atoms in a compound
Ionic Bonds-electrons are transferred
from one to another creating an electrical
,ionic charge that binds the atoms
Tends to happen between metals and
nonmetals
Looking @ p.37 ,draw what happens in a NaCl
bond
Figure 2-3 Ionic Bonding
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Go to
Section:
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
Figure 2-3 Ionic Bonding
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Go to
Section:
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1

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.37and draw the bond of H2O
molecule
Share
electrons
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.39
•Rapid movement of electrons can create regions of tiny (+) and (-) charges/As some molecules are close together,slight attra
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
 _____________-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


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
multiple
A single water molecule
can be involved in as
many as 4 H-bonds
__________________attraction between
molecules of the same
substance…water is
cohesive
Cohesion
cohesion
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
capillary action and how it is used in nature
__________________

Draws water
out of roots and
up into stems
and leaves
adhesion
adhesion
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
B. Solutions and Suspensions
Water is often in a
________________________,where 2 or
more elements or compounds are
PHYSICALLY combined
mixture
Figure 2-9 NaCI Solution
Section 2-2
ClCl-
Na+
Na+
Water
Go to
Section:
Water
Figure 2-9 NaCI Solution
Section 2-2
ClCl-
Na+
Na+
Water
Go to
Section:
Water
2 types of solutions
__________________mixture where
components evenly distributed
 Ions are surrounded by water molecules
and evenly distributed
 _____________-substance dissolved
 ______________-substance that does
dissolving
____________________-mixtures of water
and non dissolved materials—blood cells in
a suspension of water in vessels
solvent
solute
Solutions
suspension
Acids,Bases and pH-


pH
Water molecule can react to form ions.Draw
reaction as shown @ bottom of p.42:
_________________indicates concentration
of H ions in solution
Each step represents a power of 10example-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
acids
bases
buffers
Buffers are dissolved in life’s
fluids ,playing an important role
in maintaining homeostasis in
organisms
pH Scale
Section 2-2
Increasingly Basic
Oven cleaner
Increasingly Acidic
Neutral
Go to
Section:
Bleach
Ammonia solution
Soap
Sea water
Human blood
Pure water
Milk
Normal
rainfall
Acid rain
Tomato
juice
Lemon juice
Stomach acid
Interest Grabber
Life’s Backbone
Section 2-3
Most of the compounds that make up living things
contain carbon. In fact, carbon makes up the basic
structure, or “backbone,” of these compounds. Each
atom of carbon has four electrons in its outer energy
level, which makes it possible for each carbon atom to
form four bonds with other atoms.
As a result, carbon atoms can form long chains. A huge
number of different carbon compounds exist. Each
compound has a different structure. For example,
carbon chains can be straight or branching. Also, other
kinds of atoms can be attached to the carbon chain.
Go to
Section:
Interest Grabber continued
Section 2-3
1. On a sheet of paper, make a list of at least ten
things that contain carbon.
2. Working with a partner, review your list. If you
think some things on your list contain only carbon,
write “only carbon” next to them.
3. If you know other elements that are in any items
on your list, write those
elements next to them.
Go to
Section:
Concept Map
Section 2-3
Carbon
Compounds
include
Carbohydrates
Lipids
Nucleic acids
Proteins
that consist of
that consist of
that consist of
that consist of
Sugars and
starches
Fats and oils
Nucleotides
Amino Acids
which contain
which contain
Carbon,
hydrogen,
oxygen
Go to
Section:
Carbon,
hydrogen,
oxygen
which contain
which contain
Carbon,hydrogen,
oxygen, nitrogen,
phosphorus
Carbon,
hydrogen,oxygen,
nitrogen,
III. Carbon Compounds
In the 1800’s,chemists thought compounds created
by living things –organic compounds-were 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.
Organic Chemistry
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,
3)C can bond to other
C’s in single,double or triple bonds
4)C can form chains
and rings
METHANE
ACETYLENE
butadiene
Isooctane
Forms millions of different complex
structures.
BENZENE RING
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 compounds
monomers
polymerization
polymers
The 4 groups of macromolecules
are____________________________
Carbohydrates,nucleic acids,lipids
and proteins
C.Carbohydrates
Made up of C,H and O in 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 energyf-or
cell activities
sucrose
Starches are complex carbohydrates-stores extra
energy
Single sugars are called
______________________,like glucose,galactose and
fructose.-CARB MONOMER
Sucrose=disaccharide-made of 2 sugars(notice
structure in picture)
_________________are large molecules formed from
monosaccharides polysaccharides
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.
Figure 2-13 A Starch
Section 2-3
Starch
Glucose
Go to
Section:
D. Lipids
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
insoluble
Fats,oils,waxes and
steroids
•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________________.
solids
Saturated fats
If there is at least 1 C-C double bond ,it is called
______________________.These are
________________@ room temp.example-olive oil
liquids
unsaturated
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
polyunsaturated
E.____________________=macromolecules containing
C,H,O,N and P
__________________=are polymers
assembled from monomers called
Nucleic acids
nucleotides
Nucleotides contain…
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_________________
. Single strand
ribonucleic
acid/RNA
ribose
heredity
___________________________________-contains
genetic code and has the sugar
____________________________.
Double helix
Contains deoxyribose
For heredity
deoxyribose
Deoxyribonucleic
acid/DNA
_________=macromolecules containing C,H,O
and N and composed of amino acids
____________ are compounds w/ an
amine group(-NH2) on one end and a
carboxyl group(-COOH) on the other
end.
Look @ Fig 2-16 on p. 47
Proteins
Amino acids
More than 20 amino acids in nature
All amino acids alike in regions where they may be
joined by covalent bond.Thus any amino acid can be
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____.
R
DNA
Figure 2-16 Amino Acids
Section 2-3
Amino group
Carboxyl group
General structure
Go to
Section:
Alanine
Serine
Figure 2-17 A Protein
Section 2-3
Amino
acids
Go to
Section:
Each protein has a specific role….various functions
include:




control _____________rates. (enzymes).
regulate cell processes .
forming bones and muscles
transporting substances into and out of cells
fighting diseases
reaction
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.
maintain a protein’s shape.
Interest Grabber
Section 2-4
Matter and Energy
Have you ever sat around a campfire or watched
flames flicker in a fireplace? The burning of wood is
a chemical reaction—a process that changes one
set of chemicals into another set of chemicals. A
chemical reaction always involves changes in
chemical bonds that join atoms in compounds. The
elements or compounds that enter into a chemical
reaction are called reactants. The elements or
compounds produced by a chemical reaction are
called products. As wood burns, molecules of
cellulose are broken down and combine with
oxygen to form carbon dioxide and water vapor, and
energy is released.
Go to
Section:
1. What are the reactants when wood burns?
2. What are the products when wood burns?
3. What kinds of energy are given off when wood
burns?
4. Wood doesn’t burn all by itself. What must you
do to start a fire? What does this mean in terms of
energy?
5. Once the fire gets started, it keeps burning.
Why don’t you need to keep restarting the fire?
Go to
Section:
IV. Chemical Reactions and Enzymes


Chemical
reactions=_____________________________
Some are fast and some are slow
The elements entering into the reaction are
_________and that which is produced are
the _____________.
reactants
Process that changes one set of
chemicals into another set of
chemicals
products
CO2 + H2OH2CO3
reaction that allows release
of CO2 from the bloodstream
products
reactants
Chemical reactions always involve the
breaking of bonds in ____________ and
the formation of new bonds in
_____________.
reactants
products
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
exothermic
Chemical reactions that require energy are
called_________________ and usually doesn’t
occur by itself---NEEDS AN ENERGY SOURCE
Example: 2 H2O 2H2 + O2 requires an
electrical current
endothermic
Figure 2-19 Chemical Reactions
Section 2-4
Energy-Absorbing Reaction
Energy-Releasing Reaction
Activation
energy
Products
Activation energy
Reactants
Reactants
Products
Go to
Section:
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
photosynthesis
2. Activation energy_______________________________________
Energy needed to get
a reaction started
Effect of Enzymes
Section 2-4
Reaction pathway
without enzyme
Activation energy
without enzyme
Reactants
Reaction pathway
with enzyme
Activation
energy
with
enzyme
Products
Go to
Section:
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
Proteins that act as
biological catalyst
catalyst
Carbonic anhydrase
C. Enzyme Action
Reactants must collide w/
sufficient energy to make
_____________.
product
1. ENZYME-SUBSTRATE COMPLEX-enzymes provide
a site where reactants can be brought together to
react,thus reducing energy needed for the reaction
Reactants of enzyme-catalyzed reactions are
called _________________.
Enzymes themselves unchanged in a reaction
Often end in –ase/sugars in -ose
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.
substrates
Active site
Figure 2-21 Enzyme Action
Section 2-4
ADP
Enzyme
(hexokinase)
Substrates
Products
Glucose-6phosphate
Products
are released
ATP
Active site
Enzyme-substrate
complex
Substrates
are converted
into products
Go to
Section:
Glucose
Substrates
bind to
enzyme
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.