3-2: Water and Solutions
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What makes water a unique substance?
How does the presence of substances
dissolved in water affect the properties of
water?
Intro to Water
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The bodies of all living organisms; humans
to trees to jellyfish, are composed of cells
that are mostly water
The chemical reactions of life take place in
an aqueous environment (cytoplasm,
water, humid air)
Water has very unique properties
Describe the structure of a
water molecule.
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H2O
2 Hydrogen atoms + 1 Oxygen atom
Polar covalent bonding
Electrons are closer to oxygen
Bent/ angled, not straight line
Because of polarity – waters are
attracted to other water molecules
Structure of water molecules
Explain how water’s polar nature affects
its ability to dissolve substances
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Water is a polar compound
The Oxygen region is slightly negative and the
Hydrogen regions are slightly positive, but the overall
compound is neutral.
Water dissolves other polar compounds (protein and
sugar) “like dissolves like”
Water also dissolves ionic compounds (NaCl) because
the salt ionizes/dissociates and it attracted to the
polar regions. (see pg. 53)
ION concentration is CRUCIAL to life functions.
Hydrogen Bonding
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The negative regions near the Oxygen
of one water attract the positive regions
near the Hydrogen of another water.
Waters link to other waters with
‘hydrogen bonds’ which are very weak
There are so many H bonds that
collectively they are strong
List two of water’s properties that
result from hydrogen bonding
1.
2.
Cohesion and adhesion = water
bonding to other waters and water
being attracted to other substances
like glass.
Temperature moderation = water has
to gain lots of heat to increase in
temperature and must give up a lot of
heat to decrease in temperature
Impact of waters unique
properties
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Body temp stays steady
Evaporative cooling
Coastal temperatures are buffered
Lakes don’t freeze solid
Plants are able to PULL water up stem
instead of relying on push of air
pressure
3-3: Carbon Compounds
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What are chemicals of life made from?
What is the role of carbohydrates in
cells?
What do lipids do?
What determines the functions of a
protein?
What do nucleic acids do?
Building Blocks of Life
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Organic compounds = those containing
chains or rings of carbon covalently
bonded together.
C typically bonds to H, O, N, P, S
Large carbons molecules are called
macromolecules
Polymerization
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Smaller, simpler molecules used to build
large compounds are called monomers
Chains of repeating small units are
called polymers
Monomers are linked using a
condensation reaction
Polymers are split using hydrolysis
Analogies for Polymerization
Monomer (small
units)
Initial joining –
polymerization
Final product polymer
Letter, letters of
alphabet
Words
paragraph
Student = 1
Elementary class =
25
Graduating class =
250
Amino acids
Polypeptide chain
Protein
Fatty acids and
glycerol
Lipids
Nitrogenous bases
(A, T, C, G, U)
Nucleotides; genes
DNA and RNA
Saccharides,
monosaccharides,
simple sugars
Disaccharides
Polysaccharides;
complex carbs,
starch, cellulose, etc
ENERGY
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It requires a lot of energy to run a cell
The currency of the cell is called ATP
Adenosine tri phosphate
The three phosphate groups (PO4-3)
have much bond energy
ATP + H2O  ADP + P + energy
ATP – Adenosine tri phosphate
Three (tri) phosphate groups
Adenosine
Carbohydrates
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Monosaccharides
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Disaccharides
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Simple sugars
Blood glucose
Immediate energy
Made in photosynthesis
Two sugars
Sucrose or table sugar
Transport format in plants
Polysaccharides 
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‘complex carbohydrates
Many hundreds of sugars
“starch”
Storage form of sugar and energy
Starch, glycogen and cellulose
C
A
R
B
O
H
Y
D
R
A
T
E
S
Functions
Monomer
Version
Saccharide
glucose
Monosaccharides Energy;
Immediate
Glucose, fructose
energy
FUEL
Sources
Blood sugar –
REQUIRED by
ALL cells
Corn syrup,
fruit sugars
Polymers
Starch,
carbs.
Disaccharides
sucrose
Transport
of energy
in plants
Refined sugar aka
“table sugar”
Fruits
vegetables
Elements
Polysaccharides
Starch, ‘complex
carbs’, fiber,
wood
Energy
storage;
“stored
energy” or
“long term
energy”
Grains – corn,
wheat, rice, and
things made
with flour, oats
Potatoes, barley
CH2O
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Carbohydrates are
molecules made of
sugars.
A sugar contains
carbon, hydrogen,
and oxygen in a
ratio of 1:2:1.
Glucose is a
common sugar
found in grape juice.
Lipids
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Very large
Nonpolar ( not water soluble )
Glycerol + fatty acids
Hydrophilic and hydrophobic regions are important to
construction of cell membranes ( phospholipids)
In the body fat has many forms and functions that
include
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Insulation, both thermal and electrical
Hormonal messengers
Cushion of vital organs
Energy STORAGE – for long, long term storage –
“emergency”
L
I
P
I
D
S
Monomer
Versions
Functions
Sources
Glycerol
Fatty acid
Fats
Saturated
Unsaturated
Insulation
•Thermal
•Electrical
Meats/steak
fat
Waxes
Cushion
Polymer
Lipids
Elements
CH
(few O)
“fuels”
“Hydrocarbons”
Whole milk
Oils
Seeds/nuts
Cell membrane Olives
Phospholipids
Hormones
Egg-yolk
STORED
energy
Oil – fried
foods
Proteins
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Very important
Made of pieces called amino acids whose sequence is
coded for by DNA
Can be used for the following:
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Muscle contraction
Neurotransmitters
Transporters like hemoglobin
Defenses like antigens and antibodies
Structures like nails, hair, tendon and hooves
Enzymes for reactions
Messengers like insulin
Channeling of compounds into cells
P
R
O
T
E
I
N
S
Elements
Versions
Functions
Sources
C H O and
N, some S
Many forms
Can be
globular,
sheet like
see notes
on previous
slide
Meat/tissue
Monomers
Specific
Amino acids shape
Milk
Dairy products
Seeds/ nuts/
beans
Soy
Peanut butter
Polymers
Egg (white)
Polypeptides
or proteins
Nucleic acids
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These molecules are for storage of INFORMATION
The DNA and RNA code for how to make the proteins
that compose the cell and run the cell
Monomers are nucleotides
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Adenine
Guanine
Cytosine
Thymine and
Uracil
N
U
C
L
E
I
C
A
C
I
D
ELEMENTS
CHNOS and
P
Monomers
Nitrogenous
bases and
Nucleotides
Polymers
DNA
RNA
Versions Functions
DNA
RNA
Store
information
Sources
Anything with
cells
– eat cell
Regulate the
– eat nucleus
building of proteins – get a supply
of nucleotides
Cell division and
growth
RNA makes up
ribosomes
“YOU ARE WHAT YOU EAT”
3-4: Energy and Metabolism
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Where so living things get energy?
How do chemical reactions occur?
Why are enzymes important to living
organisms?
Changing Matter
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A key feature of life is change, and change
requires energy
Energy can be in many forms, including of
heat, light or chemical energy.
Physical change  form or shape of matter
changes (sheet of paper to shredded
document)
Chemical change  substances change
(piece of tree burns and becomes CO2 ,
H2O vapor and ash)
Conservation
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Conservation of Mass
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Matter is neither created nor destroyed in
any change. The same mass (amount
of matter) is there before and after the
reaction
Conservation of Energy
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Every change in matter requires a change
in energy. Energy may change forms, but
the total amount of energy does
not change.
Chemical Reactions
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During a chemical change, a chemical
reaction takes place where bonds
between atoms are broken and new
bonds form.
reactant(s)
CO2 + H2O
product(s)
H2CO3
“carbon dioxide plus water yield carboxylic acid”
2 Important Reactions
Photosynthesis
6 CO2 + 6 H2O
C6H12O6 + 6 O2
Cellular Respiration
C6H12O6 + 6 O2
6 CO2 + 6 H2O
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sunlight and chlorophyll
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Activation Energy
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Reactions need the right
conditions
Atoms must be close
enough, long enough for
new bonds to form
Collisions must have enough
energy
Molecules must have the
correct alignment
Energy to ‘start’ a reaction is
called Activation Energy
Biological Reactions
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Living organisms have multiple chemical
reactions occurring constantly
These are directed by enzymes
Enzymes  molecules that increase the
speed of a biochemical reaction without
being consumed (part of) the reaction.
Enzymes are made of protein. They
could also be called catalysts
Enzymes
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Substrate – what the enzyme attaches
to (the reactant)
Active site – where the enzyme and the
substrate fit together
Substrate(s) + enzyme  product(s) + enzyme
S + E  SE complex  P + E