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Matter

The “stuff” of the universe

Anything that has mass and takes up space

States of matter

Solid – has definite shape and volume

Liquid – has definite volume, changeable shape

Gas – has changeable shape and volume
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Energy

The capacity to do work (put matter into motion)

Types of energy


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Kinetic – energy in action
Potential – energy of position; stored (inactive)
energy
Energy Concepts
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Forms of Energy




Chemical – stored in the bonds of chemical
substances
Electrical – results from the movement of charged
particles
Mechanical – directly involved in moving matter
Radiant or electromagnetic – energy traveling in
waves (i.e., visible light, ultraviolet light, and
X-rays)
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Energy Form Conversions


Energy is easily converted from one form to
another
During conversion, some energy is “lost” as heat
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Composition of Matter



Elements – unique substances that cannot be
broken down by ordinary chemical means
Atoms – more-or-less identical building blocks for
each element
Atomic symbol – one- or two-letter chemical
shorthand for each element
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Properties of Elements

Each element has unique physical and chemical
properties


Physical properties – those detected with our
senses
Chemical properties – pertain to the way atoms
interact with one another
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Major Elements of the Human Body

Oxygen (O),Carbon (C),Hydrogen (H),Nitrogen (N)

Lesser elements make up 3.9% of the body and
include:


Calcium (Ca), phosphorus (P), potassium (K), sulfur
(S), sodium (Na), chlorine (Cl), magnesium (Mg),
iodine (I), and iron (Fe)
Trace elements make up less than 0.01% of the body

They are required in minute amounts, and are found
as part of enzymes
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Atomic Structure
 The nucleus consists of neutrons and protons



Neutrons – have no charge and a mass of one atomic
mass unit (amu)
Protons – have a positive charge and a mass of
1 amu
Electrons are found orbiting the nucleus

Electrons – have a negative charge and 1/2000 the
mass of a proton (0 amu)
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Models of the Atom


Planetary Model – electrons move around the
nucleus in fixed, circular orbits
Orbital Model – regions around the nucleus in
which electrons are most likely to be found
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Models of the Atom
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Figure 2.1
Identification of Elements



Atomic number – equal to the number of protons
Mass number – equal to the mass of the protons
and neutrons
Atomic weight – average of the mass numbers of
all isotopes
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Identification of Elements


Isotope – atoms with same number of protons but a
different number of neutrons
Radioisotopes – atoms that undergo spontaneous
decay called radioactivity
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Identification of Elements: Atomic Structure
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Figure 2.2
Identification of Elements: Isotopes of Hydrogen
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Figure 2.3
Molecules and Compounds


Molecule – two or more atoms held together by
chemical bonds
Compound – two or more different kinds of atoms
chemically bonded together
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Mixtures and Solutions


Mixtures – two or more components physically
intermixed (not chemically bonded)
Solutions – homogeneous mixtures of components

Solvent – substance present in greatest amount

Solute – substance(s) present in smaller amounts
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Concentration of Solutions

Percent, or parts per 100 parts

Molarity, or moles per liter (M)

A mole of an element or compound is equal to its
atomic or molecular weight (sum of atomic
weights) in grams
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Colloids and Suspensions


Colloids (emulsions) – heterogeneous mixtures
whose solutes do not settle out
Suspensions – heterogeneous mixtures with visible
solutes that tend to settle out
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Mixtures Compared with Compounds

No chemical bonding takes place in mixtures

Most mixtures can be separated by physical means

Mixtures can be heterogeneous or homogeneous

Compounds cannot be separated by physical
means

All compounds are homogeneous
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Chemical Bonds

Electron shells, or energy levels, surround the
nucleus of an atom

Bonds are formed using the electrons in the
outermost energy level


Valence shell – outermost energy level containing
chemically active electrons
Octet rule – except for the first shell which is full
with two electrons, atoms interact in a manner to
have eight electrons in their valence shell
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Chemically Inert Elements

Inert elements have their outermost energy level
fully occupied by electrons
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Figure 2.4a
Chemically Reactive Elements

Reactive
elements do
not have their
outermost
energy level
fully occupied
by electrons
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Figure 2.4b
Types of Chemical Bonds

Ionic

Covalent

Hydrogen
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Ionic Bonds

Ions are charged atoms resulting from the gain or
loss of electrons

Anions have gained one or more electrons

Cations have lost one or more electrons
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Formation of an Ionic Bond

Ionic bonds form between atoms by the transfer of
one or more electrons

Ionic compounds form crystals instead of
individual molecules

Example: NaCl (sodium chloride)
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Formation of an Ionic Bond
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Figure 2.5a
Formation of an Ionic Bond
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Figure 2.5b
Covalent Bonds

Covalent bonds are formed by the sharing of two
or more electrons

Electron sharing produces molecules
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Single Covalent Bonds
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Figure 2.7a
Double Covalent Bonds
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Figure 2.7b
Triple Covalent Bonds
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Figure 2.7c
Polar and Nonpolar Molecules

Electrons shared equally between atoms produce
nonpolar molecules

Unequal sharing of electrons produces polar
molecules

Atoms with six or seven valence shell electrons are
electronegative

Atoms with one or two valence shell electrons are
electropositive
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Comparison of Ionic, Polar Covalent, and
Nonpolar Covalent Bonds
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.9
Hydrogen Bonds

Too weak to bind atoms together

Common in dipoles such as water

Responsible for surface tension in water

Important as intramolecular bonds, giving the
molecule a three-dimensional shape
PLAY
Hydrogen Bonds
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Hydrogen Bonds
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.10a
Chemical Reactions

Occur when chemical bonds are formed,
rearranged, or broken

Written in symbolic form using chemical equations

Chemical equations contain:

Number and type of reacting substances, and
products produced

Relative amounts of reactants and products
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Examples of Chemical Reactions
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Patterns of Chemical Reactions

Combination reactions: Synthesis reactions which
always involve bond formation
A + B  AB
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Patterns of Chemical Reactions

Decomposition reactions: Molecules are broken
down into smaller molecules
AB  A + B
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Patterns of Chemical Reactions

Exchange reactions: Bonds are both made and
broken
AB + C  AC + B
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Oxidation-Reduction (Redox) Reactions

Reactants losing electrons are electron donors and
are oxidized

Reactants taking up electrons are electron
acceptors and become reduced
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Energy Flow in Chemical Reactions


Exergonic reactions – reactions that release energy
Endergonic reactions – reactions whose products
contain more potential energy than did its reactants
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Reversibility in Chemical Reactions

All chemical reactions are theoretically reversible
A + B  AB
AB  A + B

If neither a forward nor reverse reaction is
dominant, chemical equilibrium is reached
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Factors Influencing Rate of Chemical Reactions



Temperature – chemical reactions proceed quicker
at higher temperatures
Particle size – the smaller the particle the faster the
chemical reaction
Concentration – higher reacting particle
concentrations produce faster reactions
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Factors Influencing Rate of Chemical Reactions


Catalysts – increase the rate of a reaction without
being chemically changed
Enzymes – biological catalysts
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Biochemistry

Organic compounds


Contain carbon, are covalently bonded, and are
often large
Inorganic compounds

Do not contain carbon

Water, salts, and many acids and bases
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Properties of Water



High heat capacity – absorbs and releases large
amounts of heat before changing temperature
High heat of vaporization – changing from a liquid
to a gas requires large amounts of heat
Polar solvent properties – dissolves ionic
substances, forms hydration layers around large
charged molecules, and serves as the body’s major
transport medium
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Properties of Water


Reactivity – is an important part of hydrolysis and
dehydration synthesis reactions
Cushioning – resilient cushion around certain body
organs
PLAY
InterActive Physiology®:
Fluid, Electrolyte, and Acid/Base Balance: Introduction to Body Fluids
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Salts

Inorganic compounds

Contain cations other than H+ and anions other
than OH–

Are electrolytes; they conduct electrical currents
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Acids and Bases

Acids release H+ and are therefore proton donors
HCl  H+ + Cl –

Bases release OH– and are proton acceptors
NaOH  Na+ + OH–
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Acid-Base Concentration (pH)

Acidic solutions have higher H+ concentration and
therefore a lower pH

Alkaline solutions have lower H+ concentration
and therefore a higher pH

Neutral solutions have equal H+ and OH–
concentrations
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Acid-Base Concentration (pH)

Acidic: pH 0–6.99

Basic: pH 7.01–14

Neutral: pH 7.00
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Figure 2.13
Buffers

Systems that resist abrupt and large swings in the
pH of body fluids

Carbonic acid-bicarbonate system

Carbonic acid dissociates, reversibly releasing
bicarbonate ions and protons

The chemical equilibrium between carbonic acid
and bicarbonate resists pH changes in the blood
PLAY
InterActive Physiology®:
Fluid, Electrolyte, and Acid/Base Balance: Acid/Base Homeostasis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Organic Compounds

Molecules unique to living systems contain carbon
and hence are organic compounds

They include:

Carbohydrates

Lipids

Proteins

Nucleic Acids
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Carbohydrates

Contain carbon, hydrogen, and oxygen

Their major function is to supply a source of
cellular food

Examples:

Monosaccharides or simple sugars
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Figure 2.14a
Carbohydrates

Disaccharides or double sugars
PLAY
Disaccharides
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Figure 2.14b
Carbohydrates

Polysaccharides or polymers of simple sugars
PLAY
Polysaccharides
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Figure 2.14c
Lipids

Contain C, H, and O, but the proportion of oxygen
in lipids is less than in carbohydrates

Examples:

Neutral fats or triglycerides

Phospholipids

Steroids

Eicosanoids
PLAY
Fats
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Neutral Fats (Triglycerides)

Composed of three fatty acids bonded to a glycerol
molecule
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Figure 2.15a
Neutral Fats (Triglycerides)
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Other Lipids
 Phospholipids – modified triglycerides with two
fatty acid groups and a phosphorus group
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Figure 2.15b
Other Lipids


Steroids – flat molecules with four interlocking
hydrocarbon rings
Eicosanoids – 20-carbon fatty acids found in cell
membranes
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Figure 2.15c
Representative Lipids Found in the Body



Neutral fats – found in subcutaneous tissue and
around organs
Phospholipids – chief component of cell
membranes
Steroids – cholesterol, bile salts, vitamin D, sex
hormones, and adrenal cortical hormones
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Representative Lipids Found in the Body



Fat-soluble vitamins – vitamins A, E, and K
Eicosanoids – prostaglandins, leukotrienes, and
thromboxanes
Lipoproteins – transport fatty acids and cholesterol
in the bloodstream
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Amino Acids

Building blocks of protein, containing an amino
group and a carboxyl group

Amino group NH2

Carboxyl groups COOH
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Amino Acids
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Figure 2.16a–c
Protein

Macromolecules composed of combinations of 20
types of amino acids bound together with peptide
bonds
Peptide bond
H
H
R
O
N
C
C
OH
H
Amino acid
+
H
H
R
O
N
C
C
OH
H
Amino acid
Dehydration H O
2
synthesis
Hydrolysis
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H
H2O
H
R
O
H
R
O
N
C
C
N
C
C
H
H
OH
Dipeptide
Figure 2.17
Structural Levels of Proteins

Primary – amino acid sequence

Secondary – alpha helices or beta pleated sheets
PLAY
Chemistry of Life:
Introduction to Protein Structure
PLAY
Chemistry of Life:
Proteins: Primary Structure
PLAY
Chemistry of Life:
Proteins: Secondary Structure
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Structural Levels of Proteins


Tertiary – superimposed folding of secondary
structures
Quaternary – polypeptide chains linked together in
a specific manner
PLAY
Chemistry of Life:
Proteins: Tertiary Structure
PLAY
Chemistry of Life:
Proteins: Quaternary Structure
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Structural Levels of Proteins
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Figure 2.18a–c
Structural Levels of Proteins
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Figure 2.18b,d,e
Fibrous and Globular Proteins


Fibrous proteins

Extended and strand-like proteins

Examples: keratin, elastin, collagen, and certain
contractile fibers
Globular proteins

Compact, spherical proteins with tertiary and
quaternary structures

Examples: antibodies, hormones, and enzymes
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Protein Denuaturation

Reversible unfolding of proteins due to drops in
pH and/or increased temperature
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Figure 2.19a
Protein Denuaturation

Irreversibly denatured proteins cannot refold and
are formed by extreme pH or temperature changes
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Figure 2.19b
Molecular Chaperones (Chaperonins)

Help other proteins to achieve their functional
three-dimensional shape

Maintain folding integrity

Assist in translocation of proteins across
membranes

Promote the breakdown of damaged or denatured
proteins
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Characteristics of Enzymes

Most are globular proteins that act as biological
catalysts

Holoenzymes consist of an apoenzyme (protein)
and a cofactor (usually an ion)

Enzymes are chemically specific

Frequently named for the type of reaction they
catalyze

Enzyme names usually end in -ase

Lower activation energy
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Characteristics of Enzymes
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Figure 2.20
Mechanism of Enzyme Action

Enzyme binds with substrate

Product is formed at a lower activation energy

Product is released
PLAY
How Enzymes Work
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Active site
Amino acids
+
Enzyme (E)
Substrates (S)
Enzyme-substrate
complex (E-S)
H2O
Free enzyme (E)
Peptide bond
Internal rearrangements
leading to catalysis
Dipeptide product (P)
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Figure 2.21
Nucleic Acids

Composed of carbon, oxygen, hydrogen, nitrogen,
and phosphorus

Their structural unit, the nucleotide, is composed
of N-containing base, a pentose sugar, and a
phosphate group

Five nitrogen bases contribute to nucleotide
structure – adenine (A), guanine (G), cytosine (C),
thymine (T), and uracil (U)

Two major classes – DNA and RNA
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Deoxyribonucleic Acid (DNA)

Double-stranded helical molecule found in the
nucleus of the cell

Replicates itself before the cell divides, ensuring
genetic continuity

Provides instructions for protein synthesis
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Structure of DNA
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Figure 2.22a
Structure of DNA
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Figure 2.22b
Ribonucleic Acid (RNA)

Single-stranded molecule found in both the
nucleus and the cytoplasm of a cell

Uses the nitrogenous base uracil instead of
thymine

Three varieties of RNA: messenger RNA, transfer
RNA, and ribosomal RNA
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Adenosine Triphosphate (ATP)

Source of immediately usable energy for the cell

Adenine-containing RNA nucleotide with three
phosphate groups
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Adenosine Triphosphate (ATP)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2.23
Membrane
protein
Pi
P
Solute
Solute transported
(a) Transport work
ADP
+
Pi
ATP
Relaxed smooth
muscle cell
Contracted smooth
muscle cell
(b) Mechanical work
Pi
X
P
X
Y
+ Y
Reactants
Product made
(c) Chemical work
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Figure 2.24