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Welcome to Anatomy and Physiology
Lecture Monday’s 8:00-12:30 with 10
minute breaks each hour.
 Rebecca Hillary, Ph.D.,
 [email protected]
 Office hours:
Monday:
7:00-7:45 am; 1:00-3:30
Wednesday 11:30-12:45
Or by appointment
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 Your Responsibilities:
 Review your notes/chapters after class to
prepare for each week’s quiz.
 Be present and active in class activities and ask
questions when you don’t understand!!
 Complete occasional HW assignments.
 My Responsibilities:
 Make A and P interesting and clear!
 Be available to help you during office hours or
scheduled appointments (tutoring)
 Grade your quizzes by Wednesday so you can
pick them up early if you like.
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How will you be evaluated?
 Midterm Exam: 25%
 Final Exam: 25%
 Daily Quizzes: Added together for 30% total
 Homework/ in class activities: Added together for
20% total
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Goals for Today
 Introductions
 Introduction to A & P and Body Systems
 Part of Chapter 1 (pp1-15)
 Basic and Organic Chemistry and why it is
important to A & P
 Chapter 2
 Introduction to the cell
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What is the study of A & P ???
Anatomy:
Physiology:
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Anatomy—Levels of Study
 Gross anatomy
 Large structures
 Easily observable
Figure 14.1
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Anatomy—Levels of Study
 Microscopic Anatomy
 Very small
structures
 Can only be
viewed with
a microscope
Figure 14.4c–d
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Levels of Structural Organization
Molecules
Atoms
Chemical level
Atoms combine to
form molecules
Figure 1.1, step 1
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Levels of Structural Organization
Smooth muscle cell
Cellular level
Cells are made up of
molecules
Molecules
Atoms
Chemical level
Atoms combine to
form molecules
Figure 1.1, step 2
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Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level
Cells are made up of
molecules
Atoms
Chemical level
Atoms combine to
form molecules
Tissue level
Tissues consist of
similar types of cells
Smooth
muscle
tissue
Figure 1.1, step 3
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Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level
Cells are made up of
molecules
Atoms
Chemical level
Atoms combine to
form molecules
Tissue level
Tissues consist of
similar types of cells
Smooth
muscle
tissue
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
Blood
vessel
(organ)
Organ level
Organs are made up
of different types
of tissues
Figure 1.1, step 4
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Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level
Cells are made up of
molecules
Atoms
Chemical level
Atoms combine to
form molecules
Tissue level
Tissues consist of
similar types of cells
Smooth
muscle
tissue
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
Organ level
Organs are made up
of different types
of tissues
Blood
vessel
(organ)
Cardiovascular
system
Organ system level
Organ systems consist of different
organs that work together closely
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Figure 1.1, step 5
Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level
Cells are made up of
molecules
Atoms
Chemical level
Atoms combine to
form molecules
Tissue level
Tissues consist of
similar types of cells
Smooth
muscle
tissue
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
Organ level
Organs are made up
of different types
of tissues
Blood
vessel
(organ)
Cardiovascular
system
Organismal level
Human organisms
are made up of many
organ systems
Organ system level
Organ systems consist of different
organs that work together closely
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Figure 1.1, step 6
Overview of The Body Systems:
 Integumentary
 Skeletal
 Muscular
 Nervous
 Endocrine
 Cardiovascular
 Lympahtic
 Respiratory
 Digestive
 Urinary
 Reproductive
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Organ System Overview
 Integumentary
 Forms the external body
covering
 Protects deeper tissue from
injury
 Helps regulate body
temperature
 Location of cutaneous
nerve receptors
Figure 1.2a
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Organ System Overview
 Skeletal
 Protects and supports
body organs
 Provides muscle
attachment for movement
 Site of blood cell
formation
 Stores minerals
Figure 1.2b
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Organ System Overview
 Muscular
 Produces movement
 Maintains posture
 Produces heat
Figure 1.2c
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Organ System Overview
 Nervous
 Fast-acting control
system
 Responds to internal and
external change
 Activates muscles and
glands
Figure 1.2d
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Organ System Overview
 Endocrine
 Secretes regulatory
hormones
 Growth
 Reproduction
 Metabolism
Figure 1.2e
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Organ System Overview
 Cardiovascular
 Transports materials in body
via blood pumped by heart
 Oxygen
 Carbon dioxide
 Nutrients
 Wastes
Figure 1.2f
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Organ System Overview
 Lymphatic
 Returns fluids to blood
vessels
 Cleanses the blood
 Involved in immunity
Figure 1.2g
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Organ System Overview
 Respiratory
 Keeps blood supplied with
oxygen
 Removes carbon dioxide
Figure 1.2h
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Organ System Overview
 Digestive
 Breaks down food
 Allows for nutrient
absorption into blood
 Eliminates indigestible
material
Figure 1.2i
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Organ System Overview
 Urinary
 Eliminates nitrogenous
wastes
 Maintains acid-base
balance
 Regulates water and
electrolytes
Figure 1.2j
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Organ System Overview
 Reproductive
 Produces
offspring
Figure 1.2k–l
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Necessary Life Functions
 Maintain boundaries
 Movement
 Locomotion
 Movement of substances
 Responsiveness
 Ability to sense changes and react
 Digestion
 Break-down and absorption of nutrients
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Necessary Life Functions
 Metabolism—chemical reactions within the body
 Produces energy
 Makes body structures
 Excretion
 Eliminates waste from metabolic reactions
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Necessary Life Functions
 Reproduction
 Produces future generation
 Growth
 Increases cell size and number of cells
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Survival Needs
 Nutrients
 Chemicals for energy and cell building
 Includes carbohydrates, proteins, lipids,
vitamins, and minerals
 Oxygen
 Required for chemical reactions
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Survival Needs
 Water
 60–80% of body weight
 Provides for metabolic reaction
 Stable body temperature
 Atmospheric pressure
 Must be appropriate
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Interrelationships Among Body Systems
Figure 1.3
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Homeostasis
 Homeostasis—maintenance of a stable internal
environment
 A dynamic state of equilibrium
 Homeostasis is necessary for normal body
functioning and to sustain life
 Homeostatic imbalance
 A disturbance in homeostasis resulting in
disease
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Input:
Information
sent along
afferent
pathway to
Control
center
Output:
Information sent
along efferent
pathway to activate
Effector
Receptor (sensor)
Change
detected
by receptor
Stimulus:
Produces
change
in variable
Variable
(in homeostasis)
Response of
effector feeds
back to
influence
magnitude of
stimulus and
returns variable
to homeostasis
Figure 1.4
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Maintaining Homeostasis
 The body communicates through neural and
hormonal control systems
 Receptor
 Responds to changes in the environment
(stimuli)
 Sends information to control center
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Maintaining Homeostasis
 Control center
 Determines set point
 Analyzes information
 Determines appropriate response
 Effector
 Provides a means for response to the
stimulus
 Examples
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Feedback Mechanisms
 Negative feedback
 Includes most homeostatic control
mechanisms
 Shuts off the original stimulus, or reduces its
intensity
 Works like a household thermostat
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Feedback Mechanisms
 Positive feedback
 Increases the original stimulus to push the
variable farther
 In the body this only occurs in blood clotting
and during the birth of a baby
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Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level
Cells are made up of
molecules
Atoms
Chemical level
Atoms combine to
form molecules
Tissue level
Tissues consist of
similar types of cells
Smooth
muscle
tissue
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
Organ level
Organs are made up
of different types
of tissues
Blood
vessel
(organ)
Cardiovascular
system
Organismal level
Human organisms
are made up of many
organ systems
Organ system level
Organ systems consist of different
organs that work together closely
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Figure 1.1, step 6
Objectives for Chapters 2
1.
Describe the importance of chemical elements to living
organisms
2.
Describe the structure of an atom and associated
terminology.
3.
Distinguish between ionic, hydrogen, and covalent bonds
4.
List and define the life-supporting properties of water
5.
Explain the pH scale and the formation of acid and basic
solutions
6.
Describe the four macromolecules of life: Know their
components, formation, and specific examples. Also their
functions as they relate to the cell.
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Living organisms are composed of about 25 chemical
elements
 Living organisms are composed of matter, which
is anything that occupies space and has mass
(weight)
– Matter is composed of chemical elements
– Element—a substance that cannot be broken down to
other substances
– There are 92 elements in nature—only a few exist in a
pure state
– Life requires 25 essential elements; some are called
trace elements
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Trace elements are common additives to food and water
 Some trace elements are
required to prevent
disease
– Without iron, your
body cannot
transport oxygen
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Atoms consist of protons, neutrons, and electrons
 An atom is the smallest unit of matter that still retains
the properties of a element
– Atoms are made of over a hundred subatomic
particles, but only three are important for biological
compounds
– Proton—has a single positive electrical charge
– Electron—has a single negative electrical
charge
– Neutron—is electrically neutral
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Atoms consist of protons, neutrons, and electrons
 Elements differ in their number of protons, neutrons,
and electrons
 Helium has two protons, two neutrons, and two
electrons
 Carbon has six protons, six neutrons, and six electrons
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Atoms consist of protons, neutrons, and electrons
 Neutrons and protons are packed in the atom’s nucleus
– The negative charge of electrons and the positive
charge of protons keep electrons near the nucleus
– The number of protons is the atom’s atomic number
– Carbon with 6 protons has an atomic number of
6
– The atomic mass is the sum of the protons and
neutrons in the nucleus (carbon-12 is written
12C)
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Electron
cloud
6e–
Nucleus
6
Protons
Mass
number = 12
6
Neutrons
6
Electrons
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Isotopes
 Although all atoms of an element have the same atomic
number, some differ in mass number
– The variations are isotopes, which have the same
numbers of protons and electrons but different
numbers of neutrons
– One isotope of carbon has 8 neutrons instead
of 6 (written 14C)
– Unlike 12C, 14C is an unstable (radioactive)
isotope that gives off energy
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CONNECTION: Radioactive isotopes can help or
harm us
 Living cells cannot distinguish between isotopes of the
same element
– Therefore, when radioactive compounds are used in
metabolic processes, they act as tracers
– Radioactivity can be detected by instruments
 With instruments, the fate of radioactive tracers can be
monitored in living organisms
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CONNECTION: Radioactive isotopes can help or harm us
 Radioactive tracers are frequently used in medical
diagnosis
 Sophisticated imaging instruments are used to detect
them
– An imaging instrument that uses positron-emission
tomography (PET) detects the location of injected
radioactive materials
– PET is useful for diagnosing heart disorders and
cancer and in brain research
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Healthy brain
Alzheimer’s patient
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CONNECTION: Radioactive isotopes can help or harm us
 In addition to benefits, there are also dangers
associated with using radioactive substances
– Uncontrolled exposure can cause damage to some
molecules in a living cell, especially DNA
– Chemical bonds are broken by the emitted energy,
which causes abnormal bonds to form
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Electron arrangement determines the chemical
properties of an atom
 Only electrons are involved in chemical activity
 Electrons occur in energy levels called electron shells
Hydrogen
Helium
First
shell
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Second
shell
Sodium
Magnesium Aluminum
Third
shell
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Electron arrangement determines the chemical
properties of an atom
 An atom may have one, two, or three electron shells
– The number of electrons in the outermost shell
determines the chemical properties of the atom
– The first shell is full with two electrons, whereas the
second and third will hold up to eight electrons
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Elements can combine to form compounds
 Compound—a substance consisting of two or more
different elements combined in a fixed ratio
– There are many compounds that consist of only two
elements
– Table salt (sodium chloride or NaCl) is an
example
– Sodium is a metal, and chloride is a poisonous
gas
– However, when chemically combined, an edible
compound emerges
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Three Types of Bonds
 Atoms want to fill their outer electron shells
– To accomplish this, the atom can share,
donate, or receive electrons
 Ionic
 Covalent
 Hydrogen
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2.7 Ionic bonds are attractions between ions of
opposite charge
 An ion is an atom or molecule with an electrical
charge resulting from gain or loss of electrons
 When an electron is lost, a positive charge
results (cation); when one is gained, a
negative charge results (anion)
 Two ions with opposite charges attract each other
 When the attraction holds the ions together, it
is called an ionic bond
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Transfer of
electron
Na
Sodium atom
Cl
Chlorine atom
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Transfer of
electron
Na
Sodium atom
–
+
Cl
Chlorine atom
Na
Sodium ion
+
Cl
Chloride ion
–
Sodium chloride (NaCl)
Q: How are Electrolytes related to ions?
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2.8 Covalent bonds join atoms into
molecules through electron sharing
 A covalent bond results when atoms share outer-shell
electrons
– A molecule is formed when atoms are held together
by covalent bonds
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2.9 Unequal electron sharing creates polar
molecules
 Atoms in a covalently bonded molecule continually
compete for shared electrons
– The attraction (pull) for shared electrons is called
electronegativity
– More electronegative atoms pull harder
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2.9 Unequal electron sharing creates polar
molecules
 In molecules of only one element, the pull toward each
atom is equal, because each atom has the same
electronegativity
– The bonds formed are called nonpolar covalent
bonds
 In H2O the oxygen atom has a slight negative charge
and the hydrogens have a slight positive charge
– Molecules with this unequal distribution of charges
are called polar molecules
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2.9 Unequal electron sharing creates polar
molecules
 Water has atoms with different electronegativities
– Oxygen attracts the shared electrons more strongly
than hydrogen
– So, the shared electrons spend more time near
oxygen
– The result is a polar covalent bond
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(–)
(–)
O
H
H
(+)
(+)
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Hydrogen bonds are weak bonds important in the
chemistry of life
 Some chemical bonds are weaker than covalent bonds
 When Hydrogen is part of a polar covalent bond, its
partial positive charge allows it to share attractions with
other electronegative atoms
– Examples are oxygen and nitrogen
 Water molecules are electrically attracted to oppositely
charged regions on neighboring molecules (such as
other water molecules)
– Because the positively charged region is always a hydrogen
atom, the bond is called a hydrogen bond
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The Octet rule in chemistry helps predict
the types of bonds that atoms will form.
In general, an atom will be most stable if it fills its outer
shell of 8 electrons. Atoms with fewer than 4 valence
electrons tend to donate electrons and those with more tend
to accept. Those with 4 exactly can do both.
Q: Which category does each of the following fall into: N (7),
S (16), C (6), P (15), O (8), H (1), Ca (20), Fe (26), Mg (12)
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CHEMICAL REACTIONS
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WHAT IS THE DIFFERENCE BETWEEN A COMPOUND
AND A MOLECULE?
A molecule is formed when two or more atoms join together
chemically.
A compound is a molecule that contains at least two different
elements.
All compounds are molecules but not all molecules are compounds.
Q: Are the following compounds or molecules or both?
Molecular hydrogen (H2),
molecular oxygen (O2)
Water (H2O),
carbon dioxide (CO2)
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Chemical reactions make and break bonds, changing the
composition of matter
 You learned that the structure of atoms and molecules
determines the way they behave
– Remember that atoms combine to form molecules
– Hydrogen and oxygen can react to form water
2H2 + O2
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2H2O
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Chemical reactions make and break bonds, changing the
composition of matter
 The formation of water from hydrogen and oxygen is
an example of a chemical reaction
 The reactants (H2 and O2) are converted to H2O, the
product
– Organisms do not make water, but they do carry out
a large number of chemical reactions that rearrange
matter
– Photosynthesis is an example where plants drive a
sequence of chemical reactions that produce
glucose
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Organic Chemistry
 Diverse molecules found in cells are composed of
carbon bonded to other elements
– Carbon-based molecules are called organic compounds
– By sharing electrons, carbon can bond to four other atoms
– By doing so, it can branch in up to four directions
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WATER’S LIFE-SUPPORTING
PROPERTIES
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Hydrogen bonds make liquid water cohesive
 Hydrogen bonding causes molecules to stick together,
a property called cohesion
– Cohesion is much stronger for water than other
liquids
– This is useful in plants that depend upon cohesion
to help transport water and nutrients up the plant
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Hydrogen bonds make liquid water cohesive
 Cohesion is related to surface tension—a measure of
how difficult it is to break the surface of a liquid
– Hydrogen bonds are responsible for surface
tension
Q: Why do we need a towel
after we leave water?
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Water’s hydrogen bonds moderate temperature
 Because of hydrogen bonding, water has a greater
ability to resist temperature change than other liquids
– Heat is the energy associated with movement of
atoms and molecules in matter
– Temperature measures the intensity of heat
 Heat must be absorbed to break hydrogen bonds; heat
is released when hydrogen bonds form
Q: Why is a high temperature resistance important in the body?
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Water is the solvent of life
 A solution is a liquid consisting of a uniform mixture of
two or more substances
– The dissolving agent is the solvent
– The substance that is dissolved is the solute
Q: Why is the ability to dissolve solutes important in the body?
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Table salt is an example of a solute that will go into
solution in water
–Sodium and chloride ions and water are attracted to
each other because of their charge
–So the versatility of water results from its polarity.
Ion in
solution
Salt
crystal
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The chemistry of life is sensitive to acidic and basic
conditions
 A few water molecules can break apart into ions
– Some are hydrogen ions (H+)
– Some are hydroxide ions (OH–)
– Both are extremely reactive
– A balance between the two is critical for
chemical processes to occur in a living
organism
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The chemistry of life is sensitive to acidic and basic
conditions
 Chemicals other than water can contribute H+ to a
solution
– They are called acids
– An example is hydrochloric acid (HCl)
– This is the acid in your stomach that aids in
digestion
 An acidic solution has a higher concentration of H+
than OH–
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The chemistry of life is sensitive to acidic and basic
conditions
 Some chemicals accept hydrogen ions and remove
them from solution
– These chemicals are called bases
– For example, sodium hydroxide (NaOH) provides
OH– that combines with H+ to produce H2O (water)
– This reduces the H+ concentration
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The chemistry of life is sensitive to acidic and basic
conditions
 A pH scale (pH = potential of hydrogen) is used to
describe whether a solution is acidic or basic
– pH ranges from 0 (most acidic) to 14 (most basic)
– A solution that is neither acidic or basic is neutral
(pH = 7)
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pH scale
0
1
Acidic solution
Increasingly ACIDIC
(Higher concentration of H+)
Battery acid
2
Lemon juice, gastric juice
3
Grapefruit juice, soft drink,
vinegar, beer
4
Tomato juice
5
Rain water
6
Human urine
Saliva
NEUTRAL
[H+]=OH–]
7
Pure water
Human blood,
tears
8
Seawater
Increasingly BASIC
(Lower concentration of H+)
Neutral solution
9
10
Milk of magnesia
11
Household ammonia
12
Household bleach
13
Oven cleaner
Basic solution
14
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Buffers
 A buffer prevents dramatic changes in
pH
 Many body fluids have the buffering
capacity to maintain a constant
internal environment
 Physiological examples
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Acidic solution
Neutral solution
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Basic solution
Life’s molecular diversity is based on the properties of
carbon
 Methane (CH4) is one of the simplest organic
compounds
– Four covalent bonds link four hydrogen atoms to
the carbon atom
– Each of the four lines in the formula for methane
represents a pair of shared electrons
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Characteristic chemical groups help determine the
properties of organic compounds
 An organic compound has unique properties that depend upon
– The size and shape of the molecule and
– The groups of atoms (functional groups) attached to it
 A functional group affects a biological molecule’s function in a
characteristic way
 Compounds containing functional groups are hydrophilic (waterloving)
– This means that they are soluble in water, which is a necessary
prerequisite for their roles in water-based life
Q: Our cell membranes have a hydrophobic bilayer. Why is this
important?
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The Major Molecules of Life
 Biological macromolecules are the giant
molecules of life
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids
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Cells make a huge number of large molecules from a small
set of small molecules
 The four classes of biological molecules contain very
large molecules
– They are often called macromolecules because of
their large size
– They are also called polymers because they are
made from identical building blocks strung together
– The building blocks are called monomers
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 A cell makes a large number of polymers from a small
group of monomers
– Proteins are made from only 20 different amino
acids, and DNA is built from just four kinds of
nucleotides
 The monomers used to make polymers are universal
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 Monomers are linked together to form polymers
through dehydration reactions, which remove water
 Polymers are broken apart by hydrolysis, the addition
of water
 All biological reactions of this sort are mediated by
enzymes, which speed up chemical reactions in cells
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Short polymer
Unlinked
monomer
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Short polymer
Unlinked
monomer
Dehydration
reaction
Longer polymer
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Hydrolysis
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CARBOHYDRATES
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Carbohydrates
 Polysaccharides are chains of monosaccharides
which store energy or provide structure
 The storage polysaccharide in plants is
starch/cellulose
 In animals it is glycogen, which humans store
mainly in the cells of liver and muscles
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Polysaccharides are long chains of sugar units
 Starch is a storage polysaccharide composed of
glucose monomers and found in plants
 Glycogen is a storage polysaccharide composed of
glucose, which is hydrolyzed by animals when glucose
is needed
 Cellulose is a polymer of glucose that forms plant cell
walls
 Chitin is a polysaccharide used by insects and
crustaceans to build an exoskeleton
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Glucose
Glucose
Maltose
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Lipids
 Lipids are water-insoluble molecules made of C,
H, and O that store long-term energy, protect vital
organs, and form cell membranes
 Trigylcerides
 Phospholipids
 Steroids
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Lipids
 Triglycerides
 a polymer made of one molecule of glycerol and
three fatty acids
 Fats and oils
 Saturated versus Unsaturated
 Trans Fats
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Lipids
 Phospholipids:
 Make up the plasma membrane surrounding
our cells.
 The fact that phospholipid molecules have a
glycerol head that is polar and water soluble
(hydrophilic) and a fatty acid tail that is
nonpolar and water insoluble (hydrophobic) is
critical to their function as a part of cell
membranes.
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Lipids
 Steroids are a unique group of lipids that consist
of four ring compounds.
 Estrogen
 Testosterone
 Cholesterol
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Phospholipids and steroids are important lipids with a
variety of functions
 Steroids are lipids composed of fused ring structures
– Cholesterol is an example of a steroid that plays a
significant role in the structure of the cell membrane
– In addition, cholesterol is the compound from which
we synthesize sex hormones
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Proteins
 Proteins are comprised of strings of amino acids.
 Amino acids consist of a central carbon atom
bound to a hydrogen (H) atom, an amino group
(NH2), and a carboxyl group (COOH) in addition to
a unique side chain called a radical (R)
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Proteins are essential to the structures and functions of
life
 Structural proteins provide associations between body
parts and contractile proteins are found within muscle
 Defensive proteins include antibodies of the immune
system, and signal proteins are best exemplified by the
hormones
 Receptor proteins serve as antenna for outside signals,
and transport proteins carry oxygen
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Proteins
 Chains of only a few amino acids are called
peptides
 Chains of 10 or more are called polypeptides
 Proteins are polypeptide chains of at least 50
amino acids that provide structure, transport, and
movement for the body
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Proteins
 A special group of proteins are called enzymes
and they serve as catalysts for chemical reactions
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Introduction: Got Lactose?
 Most of the world’s population cannot digest milkbased foods
– They are lactose intolerant, because they lack the
enzyme lactase
 This illustrates the importance of biological molecules,
such as lactase, to functioning living organisms
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Proteins
 Enzymes speed up a reaction while not being
consumed
 Enzymes bind to substrates at a specific active
site forming an enzyme-substrate complex
 Sometimes cofactors, often called coenzymes, bind at
the active site to facilitate the reaction
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A protein’s specific shape determines its function
 A polypeptide chain contains hundreds or thousands
of amino acids linked by peptide bonds
– The amino acid sequence causes the polypeptide to
assume a particular shape
– The shape of a protein determines its specific
function
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Groove
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Groove
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A protein’s specific shape determines its function
 If for some reason a protein’s shape is altered, it can
no longer function
– Denaturation will cause polypeptide chains to
unravel and lose their shape and, thus, their
function
– Proteins can be denatured by changes in salt
concentration and pH
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A protein’s shape depends on four levels of structure
 A protein can have four levels of structure
– Primary structure
– Secondary structure
– Tertiary structure
– Quaternary structure
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A protein’s shape depends on four levels of structure
 The primary structure of a protein is its unique amino
acid sequence
– The correct amino acid sequence is determined by
the cell’s genetic information
– The slightest change in this sequence affects the
protein’s ability to function
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A protein’s shape depends on four levels of structure
 Protein secondary structure results from coiling or
folding of the polypeptide
– Coiling results in a helical structure called an alpha helix
– Folding may lead to a structure called a pleated sheet
– Coiling and folding result from hydrogen bonding between
certain areas of the polypeptide chain
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Polypeptide
chain
Collagen
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A protein’s shape depends on four levels
of structure
 The overall three-dimensional shape of a protein is
called its tertiary structure
– Tertiary structure generally results from interactions between
the R groups of the various amino acids
– Disulfide bridges are covalent bonds that further strengthen
the protein’s shape
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 Two or more polypeptide chains (subunits) associate
providing quaternary structure
– Collagen is an example of a protein with quaternary
structure
– Its triple helix gives great strength to connective
tissue, bone, tendons, and ligaments
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Four Levels of Protein Structure
Primary structure
Amino acids
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Four Levels of Protein Structure
Primary structure
Amino acids
Hydrogen
bond
Secondary structure
Alpha helix
Pleated sheet
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Four Levels of Protein Structure
Primary structure
Amino acids
Hydrogen
bond
Secondary structure
Alpha helix
Tertiary structure
Pleated sheet
Polypeptide
(single subunit
of transthyretin)
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Four Levels of Protein Structure
Primary structure
Amino acids
Hydrogen
bond
Secondary structure
Alpha helix
Tertiary structure
Pleated sheet
Polypeptide
(single subunit
of transthyretin)
Quaternary structure
Transthyretin, with
four identical
polypeptide subunits
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Nucleic Acids
 DNA
 RNA
 ATP
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Nucleic Acids
 Genes are segments of polymers called
deoxyribonucleic acid (DNA).
 Ribonucleic acid (RNA) uses DNA as a template to
form proteins.
 Both are polymers of smaller units called
nucleotides
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Nucleic Acids
 A nucleotide is made up of five-carbon sugar
bonded to one of five nitrogen-containing bases
and a phosphate group
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DNA has two
strands to form a
distinctive double
helix and the
bases offer a
specific code.
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Sugars and nitrogen bases of DNA and RNA
136
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Double Helix of DNA
 DNA is formed by two
very long
polynucleotide strands
linked along their length
by hydrogen bonds
137
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Nucleic Acids
 A special nucleotide is adenosine triphosphate
(ATP), a molecule capable of storing energy in its
phosphate-to-phosphate bonds
 All energy from the breakdown of molecules such
as glucose must be channeled through ATP
before the body can use it, thus it is often
described as the energy currency of cells
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ATP: The Energy Molecule of Cells
 Adenosine
triphosphate
 Nucleotide
- adenine,
ribose,
three
phosphate
s
 Function transfer and
storage of
energy
Insert figure 2.27 a
ATP molecule
139
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Passing on the
Genetic
Message
 Each strand is
copied
 Replication is
guided by base
pairing
 End result is
two separate
double strands
141
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Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level
Cells are made up of
molecules
Atoms
Chemical level
Atoms combine to
form molecules
Tissue level
Tissues consist of
similar types of cells
Smooth
muscle
tissue
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
Organ level
Organs are made up
of different types
of tissues
Blood
vessel
(organ)
Cardiovascular
system
Organismal level
Human organisms
are made up of many
organ systems
Organ system level
Organ systems consist of different
organs that work together closely
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Figure 1.1, step 6