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Basic Chemistry
Chapter 2
Introduction
• Since chemicals compose the body, & the sum of
the chemical reactions that takes place in the
body is called metabolism, it is important to be
familiar with basic chemistry.
Matter
• Anything that
has mass &
occupies space
• 3 States – solid,
liquid, gas
Energy
• Capacity to do work
• 2 Types – kinetic
(motion) & potential
(stored)
• 4 Forms the body uses –
Chemical – stored in
bonds of chemicals food
• Electrical – movement of
charged particles – ions
• Mechanical – moving
matter - muscles
• Radiant – travels in
waves – EM spectrum
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Elements
A chemical element is a pure
substance that consists entirely of
one type of atom.
112 elements are known with
certainty.
96% of the mass of a human is
made up of Carbon, Hydrogen,
Oxygen, and Nitrogen.
Atoms
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The study of chemistry begins with the basic
unit of matter, the atom.
Protons and
Neutrons
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The subatomic particles that make up
Electrons
atoms are
• Protons (+)
• Neutrons (0)
• Electrons (-)
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The number of protons in an atom of an
element is the element's atomic number
Mass number is the number of protons
and neutrons in the nucleus of an atom
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Atoms of the same element that differ in the
number of neutrons they contain are known
as isotopes.
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Because they have the same
number of electrons, all isotopes of
an element have the same chemical
properties.
Radioisotopes
• Isotopes that exhibit radioactive behavior
• Used to tag biological molecules so that they can
be traced through the body for medical diagnosis
and treatment
• Xrays, Nuclear Medicine, PET Scans, CT Scans,
MRI
Molecules
Compounds
• two or more atoms held
together by chemical
bonds.
• H (atom) + H (atom) →
H2 (molecule)
• two or more different
elements, the atoms of
which are chemically
united
• 4H + C = CH4 (methane)
Chemical Bonds
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The atoms in compounds are held together by chemical
bonds.
The electrons that are available to form bonds are called
valence electrons.
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The main types of chemical bonds are:
• ionic bonds
• covalent bonds
An ionic bond is formed when one or more
electrons are transferred from one atom to
another.
These positively and negatively charged atoms
are known as ions.
Ionic bonds are common in salts.
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Ionic Bonds
• double bond
• triple bond
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A covalent bond forms when electrons are
shared between atoms.
• single covalent bond
Weak bonds that bind water molecules or
different parts of the same molecule.
They are common in large, complex
organic molecules (proteins & nucleic
acids).
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Hydrogen Bonds
Patterns of Chemical Reactions
1. Synthesis – A+B = AB; Two or more atoms
form a larger atom
2. Decomposition - AB→ A+B; Molecules
are broken down
3. Exchange – AB + C →AC + B; A switch is
made
Factors Increasing the Rate of Reactions
1. Increase Temperature
2. Increase Concentration of reacting
particles
3. Decrease particle size
4. Presence of Catalyst
Biochemistry
• Inorganic
• Lack Carbon
• Small, simple
molecules
• Ex: Water, Salts,
Acids, Bases
• Organic
• Have Carbon
• Fairly large,
covalently boned
molecules
• Carbohydrates,
Lipids, Proteins,
Nucleic Acids
Water
• Most abundant inorganic compound in the body
• Accounts for about two-thirds of body weight
• Properties
• High heat capacity
• Polarity/solvent properties
• Chemical reactivity
• Cushioning
Salts
• Ionic compound that dissociates into
charged particles (other than hydrogen or
hydroxyl ions) when dissolved in water
• Called electrolytes
• Vital to body functioning
A water molecule is neutral,
but can react to form
hydrogen and hydroxide ions.
H2O   H+ + OHpH – measure of how acidic or
basic a solution is
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Acids, Bases, and pH
Acids and Bases
• Like salts, acids and bases are
electrolytes.
• That is, they ionize and then
dissociate in water and can then
conduct an electrical current.
Chemists devised a measurement system
called the pH scale to indicate the
concentration of H+ ions in solution.
The pH scale ranges from 0 to 14.
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The pH scale
The pH Scale
Acid below 7; more
H+ than OHBase above 7; less H+
than OH-
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At a pH of 7, the
concentration of H+
ions and OH- ions is
equal - Neutral
Buffers
• Living cells are extraordinarily sensitive to even
slight changes in pH; and acid-base balance is
carefully regulated by the kidneys, lungs, and a
number of chemicals called buffers, which are
present in body fluids.
• Buffer - a substance or substances that help to
stabilize the pH of a solution.
Types of Organic Compounds
• 4 main types of organic compounds are:
Carbohydrates – known as sugars, polar
molecules, most dissolve in water
Lipids – fats, nonpolar, do not dissolve in
water
Nucleic acids – DNA and RNA
Proteins – amino acids, muscles, enzymes
and hair
3 Types of Carbohydrates
• Monosaccharide: one simple sugar. Examples are
glucose, fructose(fruit sugar), galactose(milk
sugar)
• The formula for glucose is C6H12O6. Plants use
this during photosynthesis
3 Types of Carbohydrates
 Disaccharide: two simple sugars joined by a
saccharide bond.
◦ Examples are sucrose(table sugar), lactose(milk
sugar), and maltose (malt beverage sugar)
 Polysaccharide: three or more monosaccharides
combined.
◦ Examples are cellulose(cell walls), chitin
(exoskeleton), glycogen (stores glucose in liver
cells), starch (stores glucose in roots of plants)
Lipids
 Lipids are fats, waxes, phospholipids, and
steroids.
 Lipids contain carbon, hydrogen and oxygen but
have fewer oxygen atoms than carbohydrates
 Building blocks are glycerol and three fatty acids.
 Lipids are used for protection, cushion, structure, insulation,
and energy storage.
 Fats
◦ Saturated contains the maximum amount of hydrogens –
solid at room temperature – animal fats
◦ Unsaturated does not contain maximum amounts of
hydrogen so double bonds exists – liquids at room
temperature- oils
Phospholipids make up cell membranes
◦ Consists of two fatty acids and a
phosphate group
Steroids contain a 4-ringed backbone
◦ Examples: cholesterol and steroids
(hormones)
Waxes – used to form waterproof coverings
on leaves, skin, or fur
◦ Example: beeswax, ear wax
Proteins are composed of carbon, hydrogen,
oxygen, and nitrogen (sulfur is found in two
amino acids)
The building blocks of protein are amino acids
held together by a peptide bond.
Proteins
Proteins
Function in immunity, building structures,
hormones, enzymes, transporting
substances
Examples of proteins are antibodies,
muscles, ligaments, tendons, and hair.
• Enzymes are made of proteins
• Enzymes biological catalysts that enables chemical reactions to take
place in the body
• End in –ase
• Enzymes speed up chemical reactions that take place in cells
Enzyme
Nucleic Acids
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polymers assembled from individual
monomers known as nucleotides.
Nucleic Acids
Nucleotides consist of three parts:
• a 5-carbon sugar (Carbon, hydrogen, & oxygen)
• a phosphate group
• adenine, cytosine, guanine, and thymine for DNA and adenine, cytosine,
guanine, and uracil for RNA
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• a nitrogenous base
Nucleic acids store and transmit hereditary, or genetic information.
Examples:
ribonucleic acid (RNA)
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deoxyribonucleic acid (DNA)
ATP
• a modified nucleotide; it consists of an
adenine base, ribose sugar, and three
phosphate groups
• the universal energy compound used by all
cells of the body