How Matter is
Organized
•Chemical Elements
•Forms all matter
•Substances that cannot be split into simpler substances by ordinary
chemical means.
•Have letter abbreviations called chemical symbols.
•Most common elements in living things  C, H, N, O, P, S
•Trace elements are present in tiny amounts (Fe, Mn, Cu)
Structure of Atoms
• An element is a quantity
of matter composed of
atoms of the same type.
• Atoms (smallest unit of
matter that retains the
properties of an element)
contain:
– Nucleus: protons (p+) &
neutrons (neutral charge)
– Electrons (e-) surround the
nucleus as a cloud (electron
shells are designated regions
of the cloud)
Atomic Number and Mass
Number
• Atomic number is
number of protons in
the nucleus.
• Mass number is the
sum of its protons and
neutrons.
• Isotope  atoms of
same element with
different number of
neutrons (Carbon-14
& Carbon-12)
• A hepatobiliary
iminodiacetic acid
(HIDA) sc
A hepatobiliary iminodiacetic acid (HIDA) scan
Ions, Molecules, & Compounds
• Ions
– an atom that gave up
or gained an electron
• Molecule
– atoms share electrons
– written as molecular
formula showing the
number of atoms of
each element (H2O)
• The atoms of a
Chemical
molecule are held
together by forces of
attraction called
chemical bonds.
• The likelihood that an
atom will form a
chemical bond with
another atom depends
on the number of
electrons in its
outermost shell, also
called the valence shell.
• Ionic, Covalent,
Hydrogen
Bonds
Ionic Bonds
•When an atom loses or
gains a valence electron,
ions are formed (Figure
2.4a).
•Positively and negatively
charged ions are attracted
to one another.
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Covalent Bonds
• atoms of molecules sharing
one, two, or three pairs of their
valence electrons.
– Covalent bonds are
common and are the
strongest chemical bonds
in the body.
• Covalent bonds may be
nonpolar or polar.
– In a nonpolar covalent
bond, atoms share the
electrons equally
Polar Covalent Bonds
• Unequal sharing of electrons between atoms.
In a water molecule, oxygen attracts the
hydrogen electrons more strongly
Hydrogen
Bonds
– are weak
intermolecular bonds;
they serve as links
between molecules.
– help determine threedimensional shape of
large molecules
– Important in giving
water its properties
essential for life
Water is:
•
•
•
•
•
Where life first began
Depended on by all life
70-95% the mass of a cell
¾ of Earth’s surface
The only common substance to naturally
exist in all 3 states of matter
• Dynamic because of its polarity which
allows it to be attracted to other molecules
(esp. to other water molecules)
6 Properties of
Water
• 1. Water is a Powerful
Solvent
– Solute, Solution, Solvent
– Hydrophobic vs Hydrophilic
– Shell of hydration
• 2. Water is attractive
– Water adheres to a surface due
to 2 properties:
• Adhesion
• Cohesion
– These 2 properties allow for
capillary action.
• 3. Water has High Surface Tension
– Strong interaction of water molecules
– Water striders, whirly gigs, skipping rocks
• 4. Water has a High Specific Heat
– High heat is required to increase the temp. of
water and a great deal of heat must be lost in
order to decrease the temp. of water.
• 5. High Heat of Vaporization
– A great deal of energy must be present in
order to break the Hydrogen bonds to change
water from liquid to gas
• 6. Water has a high freezing point and
lower density as a solid than a liquid
– Water’s maximum density is 4 degrees
Celsius
•Acid - a substance that increases the
concentration of hydrogen ions in a
solution
•Base -a substance that reduces the
concentration of hydrogen ions in a
solution
•The pH scale is a measure of the
relative amounts of these ions in a
solution
Review
True or False
• The nucleus of an
atom is made of
protons and
electrons
• An atom with 6
electrons is a
stable atom
• Covalent bonds
involve the sharing
of electrons
• Water has many
properties due to
its polarity
• A substance that
donates hydrogen
ions is a base
What are the 3 subatomic
particles?
Protons
Neutrons
electrons
What are the 3 types of
chemical bonds?
Covalent
Hydrogen
ionic
Nitrogen has an atomic number of 7.
How many protons does it have?
Electrons? Neutrons? How many
electrons does it need to be stable?
What is its mass number?
7
7
7
3
14
Differentiate between an ion
and an isotope.
• Ions – charged atoms
• Isotope – atoms of the same element with
different numbers of neutrons
All living organisms require 4 types
of Organic Compounds:
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
**All contain**:
Carbon
Hydrogen
Oxygen
1. Carbohydrates
•
•
•
•
All carbs contain C,H,O
in a 1:2:1 ratio
Functions: Energy &
structural support
Found in foods such as:
bread, rice, pasta, fruit,
and vegetables
Exist as:
a. Monosaccharides
b. Disaccharides
c. polysaccharides
a. Monosaccharide
“simple sugar”
3 Forms
1. Glucose - made by plants;
source of energy
2. Fructose - found in fruits;
Sweetest!!
3. Galactose – found in milk
These are ISOMERS – same
chemical formula but
different structures.
b. Disaccharide
“double sugar”
3 Forms
1. Sucrose – Table Sugar
glucose + fructose
2. Maltose - Malt Sugar
glucose + glucose
3. Lactose – Milk Sugar
glucose + galactose
•How do monosaccharides form
disaccharides?
• Hydrolysis
• Dehydration synthesis
– Glycosidic linkage – covalent bond between 2 mono’s
c. Polysaccharide
“Many Sugars”
3 Forms – All composed of repeating
units of glucose.
1.
Glycogen – Energy storage in
animals. (Liver & Muscles)
2.
Starch - Energy storage in plants
(Roots, Stems, Leaves)
3.
Cellulose - Gives strength &
rigidity to plant cell
(Fiber  Prevents Colon Cancer)
2. Lipids
• Nonpolar / insoluble / hydrophobic
• 5 types: triglycerides, phospholipids,
steroids, waxes, glycolipids
• Fx: insulation, cushion, energy storage,
hormones, membrane structure, protection
against pathogens, repel water, water
conservation
Four Ring Structure of Steroids
3. Proteins
• Found in: meat, eggs,
nuts, beans, tofu
• Uses in body: muscle,
hormones, enzymes,
energy, transport of
oxygen (hemoglobin),
support, hair, nails,
skin, blood clots (fibrin)
• Monomers of proteins
are amino acids
• Amino acids join
together by peptide
bond
Formation of a Dipeptide Bond
• Dipeptides formed from 2 amino acids joined by a
covalent bond called a peptide bond
– dehydration synthesis
• Polypeptides chains contain 10 to 2000 amino acids.
Copyright 2009, John Wiley &
Sons, Inc.
4. Nucleic Acids
DNA and RNA
• Deoxyribonucleic acid (DNA)
forms the genetic code inside
each cell and thereby
regulates most of the activities
that take place in our cells
throughout a lifetime.
• Ribonucleic acid (RNA) relays
instructions from the genes in
the cell’s nucleus to guide
each cell’s assembly of amino
acids into proteins by the
ribosomes.
Nucleic Acids
• There is a base-pairing rule:
– A always bonds across from T
– C always bonds across from G
• A and G, called purines, are structures
composed of two rings
• C and T are pyrimidines – singled-ringed
structures
• A purine always pairs with a pyrimidine
and vice versa
Nucleic Acids
• Because of this, if one strand of DNA is
known, the other strand can be deciphered
• If we know that one strand of DNA has the
sequence:
ATCGGCA
• The other side must be:
TAGCCGT
Review
Short Answer
• The four organic
compounds are:
• Forms hormones and
steroids
• Energy and structural
support
• Peptide bonds
• Stores genetic
information
• Ring structure
• Long chains of
hydrogen and carbon
• Has 4 different levels
of structure
• Dehydration synthesis
• Made of sugar,
phosphates, and
nitrogen bases
• Glycogen
• Saturated or
unsaturated forms
Identify which organic molecule
each of the following represents:
•
•
•
•
•
•
•
•
•
Long straight chains
Peptide bonds
Monosaccharides
RNA or DNA
Amino acids
Triglyceride
Builds muscle
Energy
Steroids
• Potatoes, pasta,
apples, yogurt
• Fatty acids
• Fiber
• Hereditary information
• Meat, eggs, tofu, nuts
• Immunity
• Sex hormones
• Nucleotides
2.2 Life on Earth
• All living things are made of one or more cells
• There are two major types of cells
– prokaryotic cells
– eukaryotic cells
• Eukaryotic cells have 1000x volume of prokaryotic cells, but
only 100x the surface area. How can they compensate for the
small surface area to volume ratio?
Cell
Organelles
• What are organelles?
– internal compartments that
carry out specific cell
functions
• How are organelles
beneficial to a cell?
– They allow the cell to grow
larger and become more
specialized
• The cytoplasm is made up of
the watery mixture inside the
cell (called the cytosol) and
the organelles
Nucleus
• The nucleus is a membrane structure that
encloses the DNA
Vesicle
Membrane-sac that transports materials
Plant Cell
• Plant cells have
different structures
• Contains:
– Cell wall
– Chloroplast
– Vacuole (large central,
takes up most part of
cell)
Which organelle?
• Digests and
recycles with
enzymes
• Produces energy
(ATP)
• Photosynthesis
• Detoxifies/
synthesizes lipids
• Transports proteins
• Makes proteins
• Transports
products for export
• Stores water
• Modifies and sorts
proteins