Download Introduction to Chemistry

The
Chemistry of
Life
Chapter 2
vocabulary
 Atom the most basic and smallest unit of
matter
– Nucleus
 center of the atom
 holds protons and neutrons
– Contains subatomic particles
 called protons, electrons and neutrons
 Discuss next diagram
Atoms
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Nucleus;
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Protons; + charge; mass = 1AMU
 Neutrons; no charge; mass = 1AMU
Electrons: - charge; no mass
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vocabulary
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Element specific atoms of one type form pure
substances
Over 100 elements/pure substances exist
Ca calcium
 H hydrogen
 O oxygen
 Na sodium
 C carbon
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Periodic table
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Elements are organized in a table and assigned a
number
Number atomic number
Table periodic table
This your new friend…at least for this next unit!
 Get use to it
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Atomic Number
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Defines the element
Is equal to the number of protons
Is equal to the number of electrons in a neutral
atom
Always the whole number
An Element in the Periodic Table
Section 2-1
Atomic Number
6
C
Carbon
12.011
Atomic Mass
Go to
Section:
Atomic Mass
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Is equal to the number of protons and neutrons
in the nucleus of the atom
May not be a whole number on the periodic
table
In biology you may round up the mass number
to a whole number
To find the number of Neutrons

Atomic mass – atomic number = Neutrons
Isotopes of Carbon
Nonradioactive carbon-12
Nonradioactive carbon-13
6 electrons
6 protons
6 neutrons
6 electrons
6 protons
7 neutrons
Radioactive carbon-14
6 electrons
6 protons
8 neutrons
Isotopes have the same number of protons and
electrons but have a different number of neutrons
Time to play…
Candium isotope lab!!!
Energy Levels
1st
2e-
2nd 8e-
3rd 8e4th18e-
Valence Electrons
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Outer level Electrons
Bonding Electrons
How are things kept together

Ionic Bonds
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Covalent bonds
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Can create slightly different charges
Strongest chemical bond
Orbitals/shells overlap and electrons bounce back and forth
Van der Waals forces
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Transferring of electrons
Create ions
Opposite charged particles are attracted to each other
Electrons are gained/lost
Happens when molecules are super close together
Hydrogen bonding-weak bonds
Drawing molecules showing Ionic
Bonding
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Draw all atoms showing protons, and electrons
in their energy levels
Decide which electrons must be transferred in
order to fill all of the atoms outer level
Draw the electrons being transferred
Show the resulting charge on the Ions
Ionic Bonding
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
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
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
Draw the following molecules
showing them form ionic bonds
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KF
MgCl2
Chemical formulas
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CO2
3 Atoms
H2O
3 Atoms
Ca(OH)2 5 Atoms
2C6H12O6 48 atoms
Covalent Bonding
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Sharing of electrons
No ions are formed
Sharing of electrons holds it together.
Guided/independent practice
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Chemistry worksheet…time to think!
Water
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Most abundant compound found in living
things.
Water is a molecule (H2O)
Water is a polar molecule. (unequal sharing of
electrons)
Hand out chemistry worksheet!
Water
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Facts
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It is a neutral molecule
Water is the single most abundant compound on earth
It expands when it freezes
It floats when frozen
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What advantage does this play in the survival of fish and plants
75% of earth is water
The human body is 70% water
Ph of 7.0
Properties of Water
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Its Polar
It has a negative end and a positive end
 Uneven sharing of electrons
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High heat capacity
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Absorb
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Hydrogen bonds
Because of the uneven charge water atoms can
attract each other
 Cohesion: attraction between molecules of the same
substance
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Insects walking on water
Adhesion: attraction between molecules of different
substances
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Water drawn up a plant (capillary action)
Hydrogen Bonding
Water demo
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Water lab
Acids, Bases, and the pH scale
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Water is the universal solvent
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Most compounds will dissolve in water
Remember 75% of most animals are water
H20 → H+ + OHWater → Hydrogen ion + Hydroxide ion
Only about one water molecule in 55 million will form
a hydrogen ion
H+ = OH- , so water is always neutral
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PH scale – measures the concentration of
H+ and OH- ions.
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Ranges from 0-14
At 7 the concentration of H+ and OH- is equal.
(pure water)
Acid – H+ ions, 0-6
Alkaline or base- OH- ions, 8-14
Each step represents a factor of 10
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pH Scale
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
Acids
Any compound that gives off a hydrogen ion (H+) in a solution.
– HCl
– Stomach acid
– Lemon juice
– Tomato juice
Bases
Any compound that will produce hydroxide ions (OH-) in a solution.
– Human blood
– Sea water
– Oven cleaner
– Bleach
– soap
Time to play…
Ph lab
Buffers
Facts
– Most cells in animals must generally be kept at a pH level between 6.5 and
7.5
• Human blood has a pH of 7.4
– If the body’s pH level goes to high or too low then cells do not work
– Maintaining pH levels is important for homeostasis
– Large changes in pH are controlled by substances called buffers
Examples of buffer in the body’s cells
– Carbonic Acid (H2CO3)
– (H2CO3) → HCO3- + H+
– Carbonic acid dissociates in water to form bicarbonate ion and H
ions
Chemical Reactions
Everything that happens in an organism is based on chemical reactions
Definition: a chemical reaction is a process that changes one set of chemicals into
another set of chemicals
– Cellular respiration
– Formation of Carbonic Acid from carbon dioxide and water
Mixture
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2 or more elements or compounds that are
physically mixed together but not chemically
combined.
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Salt & pepper
Earth’s atmosphere
Salad
soil
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Solutions
Evenly distributed
throughout.
Solvent; does the dissolving
Solute; gets dissolved
Water is the greatest
solvent.
NaCI Solution
ClCl-
Na+
Na+
Water
Water
NaCI Solution
ClCl-
Na+
Na+
Water
Water
Suspension
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Unevenly distributed throughout. (settle out)
Water & gas
 Water & oil
 Blood
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4 Organic Compounds
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
Carbon,
hydrogen,
oxygen
which contain
which contain
Carbon,hydrogen,
oxygen, nitrogen,
phosphorus
Carbon,
hydrogen,oxygen,
nitrogen,
Organic
Compounds
Organic compounds
contains Carbon, Hydrogen
and Oxygen
Carbohydrates
Main source of energy
Monosaccharide (simple sugar)
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Glucose – produced by green plants.
Fructose – fruits, vegetables, honey.
Disaccharides (double sugar)
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Lactose – mammals milk.
Sucrose – table sugar.
Polysaccharides (complex sugar)
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Cellulose (plants)
Starch (plants)
Glycogen (animals)
Plants store carbohydrates as Starch
Glucose
Go to
Section:
Animals store carbohydrates as
Glycogen in the liver and muscles
Lipids
Stored energy
Fatty acids
Saturated fatty acids – meat & dairy.
Unsaturated fatty acids – plants.
Phospholipids
Waxes
Oils
Steroids
Lipids
What is it?
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Fat, oils, and waxes
Lipid cells together are know as adipose tissue, hey
look at that spare tire!
Adipose tissue acts to cushion vital organs
Once your body creates a fat cell, it is yours for life, you can
never get rid of it!
Functions
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Stores a huge amount of energy, even more than that
carbohydrates
But it is used for emergency situations when you run
out of carbohydrates
Types of lipids found in animals
HDL
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Known as the “good” lipid
Found in vegetables, oils, and some nuts
Helps clear out LDL of you system
Exercise will increase the levels of HDL in an
animals system
LDL
Triglycerides
Proteins
Made up of Amino acids
20 different amino acids
Structural- cell, muscle, skin, organs.
Movement
Enzymes
Proteins
Examples of proteins
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Muscle, insulin, hair
Facts
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Accounts for %50 of cells weight
Used for support, storage, transport defense,
signaling other cells
Humans have 10s of thousands of different proteins
Are made of monomers called amino acids
There are 20 different amino acids
What makes a protein function
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The order of the amino acids
Each protein has a specific order

The shape of a protein determines its function
Homeostasis: too much acid-proteins unfold. To
high a temperature: proteins unfold, to cold:
proteins cant function
3-D Protein
Nucleic Acids
Deoxyribonucleic Acid (DNA)
Ribonucleic Acid (RNA)
Contains genetic information
Controls the production of proteins
Nucleotides
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Phosphate
Sugar
base
Enzymes
Some reactions that are needed in life are too slow to
happen by themselves.
To speed up these reactions cell in plants and animals
produce catalysts.
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A substance that speeds up chemical reactions
They work by lowering the activation energy
Enzymes are proteins that act as biological catalysts
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Always end in ase
Lactase, carbonic anhydrase
Very specific
Catalyst
Substance that reduces the amount of
energy for a reaction to occur.
Catalyst in cells are proteins called
Enzymes.
The substance that the enzyme works on
are called a substrate.
Enzymes are very selective.
Enzyme animation
http://www.nd.edu/~aostafin/CRCD/DOSS/
enzymeanimation3.gif
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:
Time to play…
Enzyme lab
Organic compounds lab