Section 2.1 and 2.2
 Living
things consist of atoms of different
elements
 Ions
form when atoms gain or lose electrons
 Atoms
bonds
share pairs of electrons in covalent
 The

atom is the smallest basic unit of matter
Atoms are teeny tiny
 There
are three parts of a an atom
Subatomic
particle
Charge
Location
proton
_________
Positive
Nucleus
neutron
_________
electron
_________
Neutral
Nucleus
Electron
Surrounding
nucleus
 An
element is one particular type of atom ,
and it cannot be broken down into a simpler
substance by ordinary chemical means



Gold
Aluminum
Helium
 In
biology, there are SIX very important
elements






carbon
________
Hydrogen
oxygen
_________
Phosphorus
Sulfur
nitrogen
________
 The
number of protons determines the
identity of an element


Carbon: 6 protons
Oxygen: 8 protons
 The
number of electrons determines the
property of an element


Carbon: 6 electrons, 4 on OUTSIDE
Oxygen: 8 electrons, 6 on OUTSIDE
 Atoms
rarely are found alone in nature
will do ANYTHING to get to 8 electrons
on the outside
 They



Steal
Dump
Share
A
compound is a substance made of atoms of
different elements bonded together


Result of sharing, stealing, or dumping electrons
Atoms bonded in a specific ratio
 Carbon
bonds
can form many various __________
to
form




Carbohydrates
Proteins
Nucleic acids
Lipids
Ionic bonds
 __________________
are formed through
the electrical force between oppositely
charged ions

Opposites attract!
 Ex:


Salt aka sodium chloride (NaCl)
Positive sodium (Na+)
Negative chloride (Cl-)
 Ions
are atoms that have gained or lost one
or more electrons .
 Results in a change in electrical charge


Gain eLose e-
becomes ________________
negative
positive
becomes ________________
 Very



important to organisms
Hydrogen ions (H+) needed to produce chemical
_____________
in cells
energy
muscle
Calcium ions (Ca2+) needed for all _____________
movement in your body
Chloride ions (Cl-) needed for many chemical
signals in the brain
 Not
all atoms easily gain or lose their
electrons!
share
 Some atoms ___________
their electrons
instead!
Covalent
 _____________
Bond: forms when atoms
share a pair of electrons


Usually a very strong bond
Atoms may have several covalent bonds to share
several electrons
 Molecule:
two or more atoms held together
by covalent bonds
 Ex: carbon dioxide (CO2)


Carbon atoms needs 4 electrons to fill outer
level, oxygen needs two
Carbon shares with 2 oxygen!
1. What distinguishes one element from another?
2. Describe the formation of an ionic compound.
3. What is the difference between and ionic bond and a covalent bond?
4. How does a molecule differ from an atom?
5. Explain why a hydrogen atom can become either an ion or a part of a
molecule.
 Life
depends on hydrogen bonds in water.
 Many
compounds dissolve in water.
 Some
compounds form acids or bases.
CELLS
•Organisms’ bodies, (their _____________),
WATER
are made up of mostly ____________________
STRUCTURE
•The water in cells gives the cell _______________
TRANSPORTS
and ___________________
materials within
organisms.
•All of the processes necessary for an
organism’s life take place within the
WATERY ENVIRONMENT of the cell
______________________________
______________________
1. HIGH
SPECIFIC HEAT
______________________
2. COHESION
______________________
3. ADHESION
Negative Charge
POLAR
•Water is a “______________”
molecule
•Form when atoms in a molecule
UNEQUAL pulls on the
have ____________
ELECTRONS
_____________ they share.
Positive Charge
•Opposite charges of polar molecules can
HYDROGEN
interact to form ____________________
bonds.
•An attraction between a slightly
POSITIVE
_______________
hydrogen atom
and a slightly ______________
NEGATIVE
atom.
(Usually
_______________________________)
OXYGEN OR NITROGEN
•Hydrogen bonds are part of the
PROTEINS
structures of _______________
and
of ______________
DNA
Positive Charge
Shared Electrons
HIGH SPECIFIC HEAT
• Hydrogen bonds give water an abnormally ____________________________.
RESISTS
•Water __________________
changes in temperature because it must
_____________
more ____________________
to increase in temperature.
Absorb
heat energy
Cohesion: the attraction among
__________________
of the same
MOLECULES
substance.
Cohesion from hydrogen bonds makes
water molecules _____________________.
STICK TOGETHER
Cohesion produces __________________,
SURFACE TENSION
( “skin on water” )
Adhesion: the attraction among
__________________
MOLECULES of ______________
DIFFERENT
substances.
For example, water molecules stick to other
things.
Water in a test tube, (water is attracted
to the ____________)
GLASS
Materials such as
SUGARS
________________
and
____________
cannot be
OXYGEN
transported form one part
of an organism to another
unless they are dissolved
in blood, plant sap, or
other water based fluids.
SOLUTION
______________:
Mixture of a substance
that is the same
throughout.
SOLVENT
___________:
Substance that is present
in the greater amount and
dissolves another
substance.
SOLUTE
___________:
Substance that dissolves
in a solvent.
ACIDS
BASES
Some compounds form ______________
or _____________
BREAK UP
IONS
because they _______________
into _______________
WATER
when they dissolve in ___________.
BASE:
ACID:
Compounds
that release
a proton
- a hydrogen ion(H+) –
when it dissolves
in water
Compounds that
remove H+ ions
from
a solution
More basic
More acidic
neutral
1. How do polar molecules form hydrogen bonds?
2. What determines whether a compound will dissolve in water?
3. Make a chart that compares acids and bases.
4. How do polar molecules differ from non-polar molecules? How does
this difference affect their interactions?
5. Describe an example of cohesion or adhesion that you
might observe during your daily life.
A detailed look at the process of
polymerization
polymers from smaller
large molecules (_________)
ones (__________)
monomers
 Building
• Several step process
glucose
Both are _____________
together
enzyme
enzyme carries out a reaction between the
__________
two monomers
 This
Dehydration ___________:
synthesis
• ___________
Joins two
molecules together by REMOVING
_______
water
AKA: condensation reaction
H2O
________
two
REMEMBER, DIMER MEANS ________!
 The
enzyme can carry out numerous dehydration
molecule is
synthesis reactions until a macro ___________
created

EX: ______________
starch
Each one of
these
monomers is
glucose
___________
You better believe it!
 Process
hydrolysis
called ____________.
hydro
• “ __________”
means water
• “ __________”
means to split or loosen
lysis
adding water
• This enzyme works by _________
to a polymer
General process name: depolymerization
turning polymers back into monomers
ENZYME
H2O
What was previous a dimer is now two ______________
again
monomers
 Carbon
atoms have unique bonding
properties.
 Four
main types of carbon-based molecules
are found in living things.
PROTEIN
____________________
LIPIDS
____________________
CARBOHYDRATES
____________________
ATP
____________________
NUCLEIC ACID
____________________
 Each
subunit of a complete carbonbased molecule is called a
monomer
______________
polymer
_____________
is a large
molecule, or macromolecule, made
of many monomers bonded together
A


Monomers of a polymer may be the
same (ex. Starches)
Or different (proteins)
COMPOUND
BUILDING BLOCK
(POLYMER)
(MONOMER)
PROTEIN
AMINO ACID
LIPID (FAT)
FATTY ACID
CARBOHYDRATE
SUGARS
NUCLEIC ACIDS
NUCLEOTIDE
 Carbohydrates
are molecules composed of
hydrogen
carbon, ______________,
and oxygen



Include sugars & starches
Can be broken down to provide useable energy
for cells
Major part of plant cell structure
 The
most basic carbs are simple sugars,
monosaccharides
_______________________
polymers
are ______________
of
monosaccharides
 Polysaccharides
•USED BY CELLS FOR __________
ENERGY ___________
SOURCE
AND
__________
ENERGY____________.
STORAGE
SIMPLE CARBS = _______________________________
ONE OR TWO SUGAR MOLECULES
COMPLEX CARBS =LONG
_____________________________
CHAINS OF SUGAR
MOLECULES
_____________________________
Ex) Starches such as potato,
________________________________
pasta, bread
________________________________
 Proteins
are the most varied of the carbonbased molecules in organisms

Have a role in movement, eyesight, digestion,etc
A
protein is a polymer made of monomers
called amino acids
Amino acids
 _________________
are molecules that
contain carbon, hydrogen, oxygen, nitrogen,
and sometimes sulfur


Organisms use 20 different amino acids to build
proteins
The body makes 12 of the 20, the other 8 come
from food
CELLS
•MAKE UP _________________.
LIFE PROCESSES
•INVOLVED IN ALL _______
____________.
AMINO ACIDS
•BUILDING BLOCKS = _________
__________.
ENZYME
•_________________=
TYPE OF PROTEIN THAT STARTS
AND SPEEDS UP CHEMICAL REACTIONS IN CELLS.
 Lipids
are nonpolar molecules that include
fats, oils, and cholesterol



Contain chains of carbon bonded to oxygen &
hydrogen
Some broken down for useable energy
Others are part of a cell’s structure
Fatty acids
 ________________
are chains of carbon
atoms bonded to hydrogen atoms.


Saturated fatty acids have single carbon-carbon
bonds
Unsaturated fatty acids have double carboncarbon bonds
WATER
•DON’T MIX WITH ______________.
CELL MEMBRANE
•PHOSPHOLIPIDS – MAKE UP ________
______________.
STORE___________.
ENERGY
•FATS AND OILS THAT _________
•ORGANISMS USE FATS AND OILS WHEN THEY HAVE
CARBOHYDRATES
USED UP ___________________.
FATS
•_________SOLID AT ROOM TEMPERATURE.
OILS
•_________LIQUID AT ROOM TEMPERATURE.
ENERGY CARRYING
•MAJOR ___________
___________ MOLECULE IN CELL.
CARBOHYDRATES AND __________
LIPIDS
•ENERGY IN __________________
AND
PROTEINS
_____________________
MUST BE TRANSFERRED TO
ATP IN CELL TO BE USED.
 Detailed
instructions to build proteins are
stored in extremely long carbon-based
molecules called nucleic acids

Nucleic acids
____________________
are polymers that are
made up of monomers called nucleotides
 Nucleic
acids differ from the other carbonbased molecules


The others have a large # of functions
Nucleic acids have just 1 function… make
proteins


DNA stores info for putting amino acids together to
make proteins
RNA helps to build proteins
PROTEIN
•HAVE ALL INFO NEEDED TO MAKE __________.
BLUE PRINT
•“_______________”
OF LIFE.
•BUILDING BLOCKS OF NUCLEOTIDES
_____________.
DNA
RNA
•TWO TYPES: ________
AND _______.
1. What is the relationship between a polymer and a monomer?
2. Explain how both nucleic acids and proteins are polymers. Be sure to
describe the monomers that make up the polymers.
3. How are carbohydrates and lipids similar? How are they different?
4. Explain how the bonding properties of carbon atoms result in the
large variety of carbon-based molecules in living things?
Chemical Reactions
 Bonds
break and form during chemical
reactions.
 Chemical
reactions release or absorb energy.
Chemical Reaction... Gummy bear torture
 Bonds
break
&
form
during chemical
reactions


Plant/Animal cells break down sugars to get
usable energy
Cells build protein molecules by bonding amino
acids together
 Chemical
reactions change substances into
different substances by breaking and forming
chemical bonds

are the substance changed during a
chemical reactions
Reactants

Oxygen (O2) & Glucose (C6H12O6)
are the substances made by a
chemical reaction
 Products

Carbon Dioxide (CO2) & Water (H2O)
6O2 + C6H12O6
6CO2 + 6H2O
 Energy


is the amount of energy that will break a
bond between two atoms.
Every atom has different bond energy
Bond energy


A SPECIFIC amount of energy is needed to break bonds in an
oxygen molecule
A SPECIFIC amount of energy is needed to break bonds in a
glucose molecule
 Energy

needed to break bonds in molecules
is __________
released
is ___________
when bonds are formed
The amount of energy released is equal to the energy
that breaks the same bond

Energy needed to break apart water molecule = energy
released when hydrogen & oxygen atoms bond to form a
water molecule

reversible
Many reactions are _________________!
 The move in both directions at the same time!
 However many RXNs go from reactants to products
until the reactants are all used up

Tend to go in one direction depending on the
concentrations of the reactants and products
 They try to balance each other!

When a RXN takes place @ equal rate in both
directions, the reactant & product concentrations
stay the same
equilibrium
 This is called _________________
 Equilibrium is reached when both the reactants
and products are made at the same rate
 All


chemical reactions involve changes in
Energy added to the reactants breaks their chemical
bonds
When new bonds form in the products, energy is
released
 Energy
is both absorbed and
chemical reaction!


energy
released
during a
Some release more energy than they absorb (Generous)
Some absorb more energy than they release (Greedy)
 Generous
chemical RXNs that release more
energy than they absorb



= Exothermic reaction
Excess energy is the difference in bond energy
between the reactants and products
Excess energy is often released as heat or light

Cellular respiration releases usable energy for your
cells & heat!
 Greedy
chemical RXNs that absorb more energy
than they release

=

Endothermic
reaction
In photosynthesis, plants absorb energy from sunlight and
use that to make sugars and carbohydrates
 Some
energy must first be absorbed by the
reactants in ANY chemical reaction


The amount of energy needed will vary
is the amount of energy
that needs to be absorbed for a chemical
reaction to start
Activation energy

Push a rock up a hill
1. Hydrogen peroxide (H2O2) breaks down into water (H2O) and oxygen
(O2). Explain why this is a chemical reaction. What are the reactants
and the products in the reaction?
2. How do endothermic and exothermic reactions differ?
3. What must be true about the bond energies of the reactants and the
products of the exothermic process below. Explain.
6O2 + C6H12O6
6CO2 + 6H2O
4. Why might it not always be possible to determine the reactants and
the products in a reaction? Explain your answer in terms of chemical
equilibrium.
Enzymes
A
catalyst lowers activation energy.
 Enzymes
allow chemical reactions to occur
under tightly controlled conditions.
 To
start a chemical RXN, activation energy is
necessary


The reaction may happen very slowly
Reactants may not interact enough, may not be
high enough concentration
 Activation
energy & rate of a chemical
reaction can be changed by a chemical
catalyst


decreases
A catalyst is a substance that _______________
the activation energy needed to start a reaction
rate
Also increases the ________
of the reaction
Enzymes
 _____________
are catalysts for reactions
in living things



Lower the activation energy
Increase the rate of the reaction
Do not effect chemical equilibrium

Does not change the direction of the reaction
 Almost


all enzymes are
proteins
Depend on their structure to function correctly
Conditions such as temperature and pH can
affect the function
 An
enzyme’s structure is vital because their
shape allows only certain reactants to bind
to the enzyme

The specific reactants that an enzyme acts on
are called substrates
 Substrates
called


bind to enzymes at specific places
active sites
Substrates exactly fit the active sites of
enzymes, like a key exactly fits a lock
This is why if an enzyme’s structure changes, it
may not work
1. How does a catalyst affect the activation energy of a chemical
reaction?
2. Describe how the interaction between an enzyme and its substrates
changes a chemical reaction.
3. Some organisms live in very hot or very cold acidic environments.
Would their enzymes function in a person’s cells? Why or why not?
4. Suppose that the amino acids that make up an enzyme’s active site
are changed. How might this change affect the enzyme?