Resource: 2004. Johnson, George B. and Peter H. Raven. Biology.
Holt, Rhinehart, and Winston.
Unit 1
Principles of Cell Biology
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Chapter 1: Biology and You
Chapter 2: Chemistry of Life
Chapter 3: Cell Structure
Chapter 4: Cells and Their Environment
Chapter 5: Photosynthesis and Cellular
Respiration
Chapter 1
Biology and You
Section 1
Themes of Biology
Introduction
• Organisms:
- living things
• Biology:
- is the study of life
Characteristics of Living Organisms
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All living things share seven
characteristics:
composed of one or more cells
is able to reproduce
obtains and uses energy (to run the
processes of life)
maintains a constant internal
environment
5. passes on traits to offspring
6. responds and adjusts to the environment
7. grows and develops
• Life:
- is a defined by the presence of all of the
characteristics of living organisms at some
stage in an organism’s life.
• Science:
- from Latin for “to know, is a systematic
process of inquiry
Unifying Themes of Biology
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Theme 1: Cellular Structure and Function
Theme 2: Reproduction
Theme 3: Metabolism
Theme 4: Homeostasis
Theme 5: Heredity
Theme 6: Evolution
Theme 7: Interdependence
Theme 1: Cellular Structure and
Function
• Cells:
- are highly organized, tiny structures with
thin coverings called membranes.
- Smallest unit capable of all life functions.
- The basic structure of cells is the same in
all organisms, although some cells are
more complex than others
Theme 2: Reproduction
• Reproduction:
- the process by which organisms make
more of their own kind from one generation
to the next
Theme 3: Metabolism
• Metabolism:
- is the sum of all the chemical reactions
carried out in an organism
Theme 4: Homeostasis
• Homeostasis:
- the maintenance of stable internal
conditions in spite of changes in the
external environment
Theme 5: Heredity
• Gene:
- basic unit of heredity
- are coded in a molecule called
deoxyribonucleic acid (DNA) and
determine an organism’s traits
• Heredity:
- is the passing of traits from parent to
offspring
• Mutations:
- a change in the DNA of a gene
- majority are harmful though a few are
helpful
- when occur in sex cells they are passed
on to other generations
- when occur in body cells they are not
passed on (but may result in cancers)
Theme 6: Evolution
• Evolution:
- change in the inherited characteristics of
species over generations
• Species:
- is a group of genetically similar organism
that can produce fertile offspring
• Natural Selection:
- the process in which organisms with
favorable traits are more likely to survive
and reproduce
Theme 7: Interdependence
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Biological Community:
is a group of interacting organism
Ecology:
the study of the interactions of organisms
with one another and with the nonliving
part of their environment
• Interdependence:
- the idea that all organisms are dependent
on one another and their environment
Section 2
Biology in Your World
Solving Real-World Problems
Preserving Our Environment
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Conservation:
planned management of natural
resources
Preservation:
to maintain
Improving the Food Supply
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Genetic Engineering:
involves the transfer of genes from one
organism to another, which changes the
heredity information in its cells
Understanding the Human Genome
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Genome:
the complete genetic material contained
in an individual
in April of 2003 the mapping of the
human genome was complete
Fighting Disease
AIDS
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HIV:
causes AIDS
a virus that attacks and destroys the
human immune system
Cancer
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Cancer:
is a growth defect in cells, a breakdown
of the mechanism that controls cell
division
Emerging Disease
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West Nile:
a virus that is transmitted by mosquitoes
and can infect other animas such as
humans, birds etc
Mad Cow:
a fatal disease of cattle caused by eating
the body parts of infected animals
can infect humans when they eat meat or
other products of infected cattle
Gene Therapy
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Cystic Fibrosis:
caused by an inherited defect in a gene
a fatal disorder in which a thick sticky
mucus clogs passages in many of the
body’s organs
Gene Therapy:
the replacement of a defective gene with
a normal version
Section 3
The Scientific Processes
The Scientific Processes
• Observation
• Stages of Scientific Investigation
• Scientific Explanations
Solving Scientific Puzzles
• Observation:
- The basis of scientific research
- the act of noting or perceiving objects or
events using the senses
- is the first step in a scientific investigation
a.k.a. scientific method
Stages of Scientific Investigation
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There are generally six steps/stages
in a scientific investigation
collecting observations
asking questions
forming hypotheses
making predictions (with controlled
experiments)
drawing conclusions
Repeat
Collecting Observations
• The key to a scientific investigation is
careful observation
Asking Questions
• Questions arise from observations
Forming Hypotheses and Making
Predictions
• Hypothesis:
- an explanation that might be true
- must be testable through observations or
experimentation
• Prediction:
- the expected outcome of a test, assuming
the hypothesis is correct
Confirming Predictions
• pH:
- a relative measure of the hydrogen ion (H+)
concentration within a solution
• Experiment:
- a planned procedure to test a hypothesis
• Controlled Experiment:
- an experiment in which an experimental
group is compared with a control group
• Experimental Group:
- group that receives some type of
experimental treatment
• Control Group:
- group in an experiment that receives no
experimental treatment
• The control and experimental groups
are designed to be identical except for
on factor or variable
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Independent variable:
the factor that is changed in an experiment
Dependent variable:
the variable that is measured in an
experiment
Drawing Conclusions
• Does the result of the experiment
support the hypothesis?
Viewing Conclusions in Context
Repetition and Further Evidence
Gathered
Scientific Explanations
• Model:
- a representation of an object or system
- often used to mean a hypothetical
description
• Theory:
- a set of related hypotheses that have been
tested and confirmed many times by many
scientists
- unites and explains a broad range of
observations
Constructing a Theory
• Constructing a theory often involves
considering contrasting and conflicting
hypotheses
• Scientists evaluate each other’s work
• Scientific research must be able to be
replicated – reproduced by other
scientists
• There is no absolute certainty in a
scientific theory – the possibility
always remains that future evidence
will cause a scientific theory to be
revised or rejected
• See Flow Chart
Chapter 2
Chemistry of Life
Looking Ahead
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Section 1: Nature of Matter
Section 2: Water and Solutions
Section 3: Chemistry of Cells
Section 4: Energy and Chemical
Reactions
Section 1
Nature of Matter
Atoms
• Atoms –
- all matter consists of atoms
- are the smallest unit of matter that cannot
be broken down by chemical means
- consists of two parts: the nucleus and the
electrons
- In a neutral atom (no electrical charge)
there is one electron for every proton
• Nucleus –
- located at the center of the atoms
- is made up of positive protons and neutral
atoms
- has an overall positive electrical charge
• Electrons –
- located outside of the nucleus
- have a negative electrical charge
Elements
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Elements –
a pure substance made of only one kind
of atom
are identified by the number of protons
they have
Isotopes –
atoms of an element that contain
different numbers of neutrons
Chemical Bonding
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Chemical Bond –
force that holds two atoms together
Compound –
a substance made of the joined atoms of
two or more different elements
• Chemical Formula –
- represents a compound
- identifies the elements in the compound
and its proportions
Covalent Bonds
• Covalent Bond - Bond that forms when electrons are
shared
• Molecule –
- Is a group of atoms held together by
covalent bonds
• The arrangement of their electrons
determines how atoms bond together
• Electrons are grouped into levels
• The further the level is from the nucleus of
an atom the more energy the electrons
contain
• Each level can only hold a limited amount
of electrons
• An atom is stable when its outer energy
level is full
• In order to fill an outer energy level, and
become more stable, atoms react with
other atoms to form molecules and
compounds
Hydrogen Bonds
• Polar Molecules –
- occur when there is an unequal
distribution of negative electrical charge
• Hydrogen Bond –
- a weak chemical attraction between polar
molecules
Ionic Bonds
• Ions –
- form when an atom has gained or lost
electrons
- produces an unequal number of electrons
and protons
- gains a positive or negative electrical
charge
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Positive Ions –
Forms when an atoms loses electrons
Negative Ions –
Forms when an atom gains electrons
Ionic Bond –
A bond that forms between two oppositely
charged ions
• Bond formation only involves the outer
most electrons of an atom
Section 2
Water and Solutions
Water in Living Things
• Water has many properties that make it
important to life
• Water absorbs heat slowly and will retain it
longer than many other substances
• Many organisms release excess heat
through water evaporation
• Water helps cells maintain homeostasis
Cohesion –
• An attraction between substances of the
same kind
Hydrogen bond –
• Occurs between water molecules
• Causes surface tension
Surface tension –
• Prevents the surface of water from
stretching or breaking easily
Adhesion –
• An attraction between different substances
Capillary action –
• Water molecules move upward through a
narrow tube
• The attraction of water to the walls of the
tube suck the water up more strongly than
gravity pulls it down
Aqueous Solutions
Solution• Is a mixture in which one or more
substances are evenly distributed in
another substance
Polarity –
• The polarity of water enables many
substances to dissolve in water
• Ionic compounds and polar molecules
dissolve best in water
• Nonpolar molecules do not dissolve well in
water
• “Like” dissolves “Like”
Acids and Bases –
• Hydrogen Ion (H+)
• Hydroxide Ion (OH-)
Acids –
• Compounds that form hydrogen ions when
dissolved in water
Bases –
• Compounds that reduce the concentration of
hydrogen ions in a solution
• Many form hydroxide ions
pH scale• Based on the concentration of hydrogen ions
Section 3
Chemistry of Life
Carbon Compounds
Organic Compounds –
• Compounds that contain carbon
Four classes of Organic Compounds –
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids
Carbohydrates –
• Organic compound made of C, H, O in the
proportion 1:2:1
• Source of energy
• Found in most foods
• Are made from monosaccharides
Monosaccharides –
• Simple sugar which make up
carbohydrates
• Monosaccharide – one simple sugar
• Disaccharide – two simple sugars joined
together
• Polysaccharide – three or more simple
sugars joined together
Macromolecule –
• A large molecule made up of smaller
molecules
• Stores energy
Lipids –
• Nonpolar molecule
• Do not dissolve or dissolve poorly in water
• Includes fats, phospholipids, steroids, and
waxes
• Play an important role in the cell
membrane
Fats –
• Store energy
Glycerol –
• A three carbon molecule
Fatty acid –
• Long chains of carbon atoms with
hydrogen atoms bonded to them
Saturated Fats –
• Each carbon is bonded to two or three
hydrogen atoms
• Straight molecule
• Solid at room temperature
Unsaturated Fats –
• Each carbon is bonded to one, two, or
three hydrogen atoms
• Not a straight molecule
• Usually liquid at room temperature
Hydrogenated Vegetable Oils –
• Unsaturated fatty acids that are made into
saturated fats by adding hydrogen atoms
• Usually solid at room temperature
Proteins –
• Large molecule made up of amino acids
Amino acids –
• Small molecules that make up proteins
• Twenty different ones
• Proteins can be very different from each
other and serve many different purposes
Nucleic acids –
• Large molecule made of nucleotides
Nucleotides –
• Small molecules that make up nucleic
acids
• Have 3 parts: sugar, base, and a
phosphate group
• Two types: DNA and RNA – each with four
kinds of nucleotides
DNA vs RNA
• Deoxyribonucleic acid
• Sugar – deoxyribose
• Structure – double
helix
• Nucleotides –
cytosine, thymine,
adenine, and guanine
• Stores hereditary
information
• Ribonucleic acid
• Sugar – ribose
• Structure – single
strand
• Nucleotides –
cytosine, uracil,
adenine, and guanine
• Helps produce
proteins and acts as
an enzyme
ATP –
• Adenosine Triphosphate
• A single nucleotide with two extra energystoring phosphate groups
• Used to temporarily store energy released
during the breakdown of food
• The energy will be used in chemical
reactions
Section 4
Energy and Chemical Reactions
Introduction
Energy –
• Is the ability to move or change matter
• Exists in many forms
• Can be converted from one form to another
• Can be transferred from one object to
another
• Can be stored or released by chemical
reactions
Chemical Reaction –
• A process during which chemical bonds
between atoms are broken and new ones
are formed, producing one or more
different substances
Reactants –
• The starting materials for a chemical
reaction
Products –
• Substances formed during a chemical
reaction
• Reactant  Products
• Arrow () means “forms, produces,
yields”
Energy in Chemical Reactants
• During chemical reactions energy is either
absorbed or released
Metabolism –
• The sum of all the chemical reactions that
occur within an organism
Activation Energy –
• The energy needed to start a chemical
reaction
• Required during all chemical reactions
Enzymes
Enzymes –
• Substances that increase the speed of
chemical reactions
• Help organisms maintain homeostasis
• Most are proteins
• Are catalysts
Catalysts –
• Substances that reduce the amount of
activation energy needed for a chemical
reaction
Enzyme Specificity
• Enzymes work with only certain
substrates, “lock & key”
Substrate –
• A substance on which an enzyme acts
during a chemical reaction
Active sites –
• The deep fold on the surface of the
enzyme
• Site where the substrate fits
Factors in Enzyme Activity
• Certain factors can affect an enzyme’s
activity (effectiveness) such as:
temperature and pH