Transcript Week 1 - El Camino College

Bio 10: The Fundamentals of
Biology
Fall 2005 - 1082
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fundamentals of Biology
1. Course Summary
2. Course Curriculum
Inquiry into Life,
th
11
edition
by
Sylvia Mader
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 1: The Study of Life
The Characteristics of Life
Life is diverse yet all living things share common
characteristics:
1.
2.
3.
4.
5.
6.
Living things are organized.
Living things obtain *REQUIRE* energy
Living things can reproduce themselves
Living things respond to stimuli
Living things are “homeostatic”
Living things can - and do - adapt
1. Living things are organized.
Q. Based on this, what things are “alive”?
2. Living things acquire materials and energy.
- Photosynthetic organisms use carbon dioxide, water,
and solar energy to make food.
- Animals obtain nutrients and energy from food eaten.
- Energy is the capacity to do work.
- Many living things can convert energy to motion (or
thought!).
Q. Based on this, what things are “alive”?
3. Living things reproduce.
- Genes (DNA) contain information needed for heredity
and metabolism (those are, ALL energy-related processes).
- Metabolism is all the chemical reactions in the cell.
- Reproduction may be asexual or sexual.
Q. Based on this, what things are “alive”?
4. Living things respond to stimuli.
- Living things may respond to external stimuli
by movement toward or away from a stimulus.
- Movement constitutes part of the behavior of
an organism.
5. Living things are homeostatic.
- Homeostasis is the ability of an organism to
maintain relatively constant internal conditions.
(An example is temperature regulation in the
human body ….or….ever feel thirsty?).
- All organ systems contribute to homeostasis.
6. Living things grow AND develop.
All organisms undergo development.
7. Living things are adapted.
- Adaptations come about through evolution.
- Evolution is the process by which a species
changes through time.
- Evolution explains both the unity and diversity of life.
The Classification of Living Things
There are three main domains:
1 and 2. Archaea and Bacteria – unicellular
prokaryotes that lack a membrane-bound
nucleus.
3. Eukarya – showing cellular complexity and
having a nucleus and other organelles.
The three domains of life
Three-Domain System
• The three-domain system recognizes
three domains: Bacteria, Archaea, and
Eukarya.
• This system of classification is based on
biochemical differences that show there
are three vastly different groups of
organisms.
Archaea live in harsh environments and
may represent the first cells to have
evolved.
Bacteria, some of which cause human
diseases, are present in almost all
habitats on earth.
Many bacteria are important
environmentally and commercially.
The Domain Eukarya is divided into 4
kingdoms:
Protists (kingdom Protista)
Fungi (kingdom Fungi)
Plants (kingdom Plantae)
Animals (kingdom Animalia)
The Classification of Living Things
Domains (3: Archaea, Bacteria, Eukarya)
Kingdom
Phylum
Class
Order
Family
Genus
Species
The Classification of Living Things
• Taxomony is the science of identifying and
classifying organisms according to specific
criteria using these categories:
Kingdom
Phylum
Class
Order
Family
Genus
Species
Five-Kingdom System
• The five-kingdom system of classification is
based on structural differences and also on
modes of nutrition among the eukaryotes.
• The five kingdoms include:
• Monera (prokaryotes aka: bacteria)
• Eukaryotic kingdoms of Protista, Fungi,
Plantae, and Animalia (aka: plants and
animals).
The Classification of Living Things
• Taxomony is the science of identifying and
classifying organisms according to specific
criteria using these categories:
Kingdom
Phylum
Class
Order
Family
Genus
Species
The Classification of Living Things
Domains (3: Archaea, Bacteria, Eukarya)
Kingdom (5)
Phylum
Class
Order
Family
Genus
Species
Three-domain system of
classification
Five-kingdom system of
classification
The Classification of Living Things
Domains
Kingdom
Phylum
Class
Order
Family
Genus
Species
Scientific names are binomial names, using
genus and species.
Modern humans are Homo sapiens.
Most genera contain a number of similar
species, with the exception of Homo that
only contains modern humans.
Classification is based on evolutionary
relationships.
Each successive classification category
contains more different types of organisms
than the preceding category.
The Organization of the Biosphere
The biosphere is the zone of life in the air,
water, and land that surrounds the
planet.
Groups of individuals of a species are
called populations.
Populations of different species that
interact make up communities.
Communities plus the physical habitat
form ecosystems.
Ecosystems are characterized by chemical
cycling and energy flow.
Climate determines what ecosystem can
exist in an area.
Human populations tend to modify
ecosystems for their uses.
Loss of ecosystems results in loss of
biodiversity, the total number of species.
Preservation of ecosystems is important to
ensure our continued existence.
Loss of species threatens ecosystems.
The Process of Science
Biology, the study of life, uses the
scientific method.
The scientific method has these steps:
Observation
Hypothesis
Experiments/Further Observations
Conclusion
Theory
An experimental design contains a control
group that goes through all the steps of the
experiment but is not exposed to the factor
being tested.
Results of an experiment are called data.
Data undergo statistical evaluation.
Several theories in biology include:
Cell
Biogenesis
Evolution
Gene
Scientific studies may be carried out in the
field or in the lab.
In either type of study, scientists formulate
testable hypotheses, make observations or
perform experiments, and come to
objective conclusions.
Field Study Example
Controlled Laboratory
Experiment Example
Science and Social
Responsibility
Technology is the application of knowledge
for a practical purpose.
Technology has both benefits and
drawbacks.
Ethical and moral issues surrounding the
use of technology must be decided by
everyone.
Chapter 2: The Molecules of
Cells
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Basic Chemistry
Matter is anything that takes up space and
has weight.
All matter, living or nonliving, is made up of
elements.
Elements contain atoms.
An atom is the smallest unit of matter that
can enter chemical reactions.
Atoms have a central nucleus made up of
protons and neutrons, and shells around
the nucleus in which electrons orbit.
• inner energy shell holds two electrons
• outer energy shell holds eight electrons
The number of electrons in the outer energy
shell determines the chemical properties of
the atom.
Model of an Atom
The atomic number of an atom is its number of
protons.
• protons bear a positive electrical charge
The atomic weight of an atom is its number of
protons plus its number of neutrons.
• neutrons bear no electrical charge
• electrons bear a negative electrical
charge
An electrically neutral atom means:
number of protons = number of electrons
Elements are arranged in a periodic table:
• horizontally in order of increasing atomic
number
• vertically according to the number of electrons
in the outer shell
Atoms have an atomic symbol, atomic
number, and atomic mass.
Some atoms differ in their number of
neutrons and are called isotopes.
Carbon has 3 isotopes:
• Carbon 12 (most abundant)
• Carbon 13
• Carbon 14 (radioactive - unstable)
• Atoms form bonds to fill the outer shell
with electrons.
• When atoms bond with other atoms,
molecules are formed.
• When atoms of different elements bond,
a compound is formed.
• Two types of bonds are ionic bonds and
covalent bonds.
In ionic bonding, atoms give up or accept
electrons, resulting in ions.
Ions with opposite charges (- or +) are attracted
to each other and form an ionic bond.
Ionic Bonds
Ions can have important biological functions.
Covalent Bonds
In covalent reactions, atoms share electrons,
resulting in covalent bonds.
There are other ways of representing
covalent bonds.
Aside from single covalent bonds, double,
or triple covalent bonds can form.
The three-dimensional shape of
molecules can be represented in two
ways:
Water and Living Things
• Water is the most abundant molecule in
living things.
• Water has special traits that make it
important to life.
• Because oxygen atoms are large and
hydrogen atoms are small, water is a
polar molecule.
• Hydrogen bonds form when a
covalently-bonded H+ is attracted to a
negatively-charged atom in a
neighboring molecule.
• Because of its polarity and hydrogen
bonding, water has unique
characteristics that benefit living things.
Characteristics of water:
1.
2.
3.
4.
5.
6.
liquid at room temperature
universal solvent for polar molecules
water molecules are cohesive (sticky)
temperature of water changes slowly
high heat of vaporization
frozen water is less dense so ice floats
Another thing water can do…………………….
• Water dissociates and releases hydrogen
ions (H+) and hydroxide ions (OH-).
This means acids and bases can form!
*Which will change the pH of solutions*
• Acids are molecules that release
hydrogen ions in solution.
HCl  H+ + Cl-
• Bases are molecules that either take up
hydrogen ions or give off hydroxide ions
in solution.
NaOH  Na+ + OH-
• Concentrations of hydrogen ions or hydroxide
ions can be represented using the pH scale.
moles/liter
1 x 10 –6 [H+] = pH 6
1 x 10 –7 [H+] = pH 7
1 x 10 –8 [H+] = pH 8
Now, back to the whole “homeostasis” thing……….
• Buffers are substances that
help to resist change in pH.
Basic
Acidic
This buffer is found in YOUR BLOOD!
It is used to keep your blood pH at 7.0…..
If it gets to acidic, base forms….too basic, acids form.
A built in mechanism for blood homeostasis!
Organic Molecules
Organic molecules are found in living
things.
The chemistry of carbon accounts for
the chemistry of organic molecules.
Organic molecules are macromolecules.
Hydrocarbon chains can have functional
groups that cause the macromolecule to
behave in a certain way.
(insert text art from top right column of
page 31)
Macromolecules (polymers) are formed from
smaller building blocks called monomers.
Polymer
carbohydrate
protein
nucleic acid
Monomer
monosaccharides
amino acid
nucleotide
Carbohydrates
Carbohydrates serve as quick energy and
short-term energy storage.
They play a structural role in plants,
bacteria, and insects.
Monomers of carbohydrates are the
monosaccharides:
glucose
fructose
galactose
Structure
of Glucose
Glucose
A disaccharide is made from linking two
monosaccharides together.
Larger polysaccharides are made from linking many glucose
molecules together through condensation synthesis.
Examples of polysaccharides:
Starch
glycogen
cellulose
Lipids
Lipids serve as long-term energy stores in
cells, form membranes, and serve as
hormones and insulation.
Lipids do not dissolve in water.
Fats and oils are formed from a glycerol
molecule and three fatty acid molecules.
Structure of Triglycerides
Fatty acids are long chains of
hydrocarbons ending in - COOH
Fatty acids may be saturated fatty acids or
unsaturated fatty acids.
Some lipids are phospholipids
that form cell membranes.
Other lipids are steroids.
Examples include cholesterol, and the sex
hormones estrogen and testosterone.
Proteins
Proteins perform many functions in cells.
Proteins:
Serve as structural proteins
Act as enzymes to speed reactions
Serve as transport carriers
Act as antibodies
Allow materials to cross cell membranes
Proteins are polymers of amino acids.
Peptide bonds join amino acids.
Proteins have levels of organization.
Proteins can be denatured (broken down).
Nucleic Acids
Nucleic acids are polymers of nucleotides.
Examples include Deoxyribonucleic Acid (DNA)
and Ribonucleic Acid (RNA).
DNA is double-stranded, with
complementary base pairing.
A and T ……………….G and C
Some nucleotides also perform functions in
cells.
Adenosine triphosphate (ATP)
is the energy currency of cells.
Chapter 3: Cell Structure and
Function
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
The Cellular Level of
Organization
• Living things are constructed of cells.
• Living things may be unicellular or
multicellular.
• Cell structure is diverse but all cells
share common characteristics.
• The cell theory states:
1. All organisms are composed of one or
more cells.
2. Cells are the basic unit of structure and
function in organisms.
3. All cells come only from other cells.
• Cells are small so they can exchange
materials with their surroundings.
Think:
- How much easier is it to get to
the middle of a small cell vs. a big one?
Surface Area in general: Biology depends on it!
Increasing surface area, increases an organisms ability
To really stretch out and absorb all it can. Trust me,
Whenever it can increase surface area……it will!
-Example: your small intestine….it has finger-like projections
that stick out to grab more. To imagine how much better this
works, think of the baggage claim area of a airport…
Sizes of living things
Eukaryotic Cells
• Eukaryotic cells have a nucleus that
controls the workings of the cell.
• All cells are surrounded by a plasma
membrane made of phospholipids
and proteins.
The Plasma Membrane
• The plasma membrane regulates what
enters and exits the cell.
• Inside the plasma membrane, the nucleus
is surrounded by cytoplasm.
• Plant cells have a cell wall in addition to
the plasma membrane.
• Animal and plant cells have organelles
(literally, mini-organs!).
• Organelles compartmentalize functions
within the cell. (Just like our organs do!....little brain,
little stomach, even a little skeleton!)
• The organelles of animal and plant cells are
similar to each other except that
chloroplasts (which carry out photosynthesis)
are present only in plant cells.
Animal cell anatomy
Animal cell anatomy
Plant cell anatomy
Plant cell anatomy
Structure of the Nucleus
(the brain of the cell)
• Chromatin: DNA and proteins
• Nucleolus: Chromatin and ribosomal
subunits
• Nuclear envelope: Double membrane with
pores
• Nucleoplasm: semifluid medium inside the
nucleus.
Nucleus and nuclear envelope
Ribosomes
(Construction workers….for protein)
• Protein synthesis occurs at tiny organelles
called ribosomes.
• They literally READ a set of instructions sent
by the nucleus to make individual
proteins….each protein is individually made!
• Ribosomes can be found alone in the
cytoplasm, in groups called polyribosomes, or
attached to the endoplasmic reticulum.
The Endomembrane System
(A Fed-Ex Factory System to get things, built,
processed, packaged, AND delivered!)
• The endomembrane system consists of:
• Endoplasmic reticulum
• Golgi apparatus
• Vesicles
The Endoplasmic Reticulum
(The processing and packaging service of the cell)
• The endoplasmic reticulum (ER) is a system of
membranous channels and saccules.
• Rough ER is studded with ribosomes and is the
site of protein synthesis and processing.
• Smooth ER lacks ribosomes and is the site of
synthesis of phospholipids and the packaging
of proteins into vesicles, among other
functions.
The endoplasmic reticulum
The Golgi apparatus
(the pancake stack-packing and shipping dept. of
the cell)
• The Golgi apparatus consists of a stack of curved
saccules.
• The Golgi apparatus receives protein and also lipidfilled vesicles from the ER, packages, processes,
and distributes them within the cell.
*Think….distribution or shipping dept. It puts an
address on the package and sends it out!*
• This organelle may also be involved in secretion.
The Golgi apparatus
The Endomembrane System
(A Fed-Ex Factory System to get things, built,
processed, packaged, AND delivered!)
• The endomembrane system consists of:
• Endoplasmic reticulum (built and processed)
• Golgi apparatus (processed and packaged)
• Vesicles (delivered!)
Lysosomes and vacuoles
(the cell’s stomach)
• Lysosomes are vesicles produced by the Golgi
apparatus.
• Lysosomes contain hydrolytic enzymes and are
involved in intracellular digestion.
• Vacuoles are large membranous sacs in the
cell that store substances.
Peroxisomes
• Peroxisomes are vesicles than contain
enzymes.
• The enzymes in these organelles use up
oxygen and produce hydrogen peroxide.
• Peroxisomes are abundant in the liver
where they produce bile salts and
cholesterol and break down fats.
Energy-Related Organelles
• The two energy-related organelles of
eukaryotes are:
chloroplasts and mitochondria.
• Both organelles house energy in the form
of ATP (the energy currency for ALL life!).
Chloroplasts
• A chloroplast is bounded by two membranes
enclosing a fluid-filled stroma that contains
enzymes.
• These membranes house chlorophyll.
• Chlorophyll absorbs solar energy and
carbohydrates are made in the stroma – sooooo
this is where photosynthesis takes place!
Chloroplast structure
Mitochondria
(!!!THE POWERHOUSE!!!!)
• Mitochondria are found in both,
plant AND animal cells.
• Mitochondria are bounded by a double
membrane surrounding fluid-filled matrix –
why a DOUBLE membrane?!?!
- Good question!
Key Point about Mitochondria ------
The matrix contains enzymes that
break down carbohydrates and the
cristae house protein complexes that
produce ATP !!!!!! (your LIFE energy!)
Mitochondrion structure
The Cytoskeleton
• The eukaryotic cytoskeleton is a network of
filaments and tubules that extends from the
nucleus to the plasma membrane.
• The cytoskeleton contains three types of
elements responsible for cell shape, movement
within the cell, and movement of the cell:
•
Actin filaments
• Microtubules
• Intermediate filaments
• Actin filaments occur in bundles or
mesh-like networks.
• Actin filaments play a structural role
in intestinal microvilli and also
interact with motor molecules, such
as myosin.
Actin filaments
• Microtubles are small hollow
cylinders made of the globular protein
tubulin.
• Microtubule assembly is controlled by
the microtubule organizing center,
called the centrosome.
• Microtubules help maintain the shape
of the cell and act as tracks along
which organelles can move.
Microtubule structure
• Intermediate filaments are ropelike
assemblies of fibrous polypeptides
that support the plasma membrane
and nuclear envelope.
Structure of intermediate
filaments
Centrioles
• Centrioles are short cylinders with a
9 + 0 pattern of microtubule triplets.
• Centrioles may be involved in
microtubule formation and
disassembly during cell division
and in the organization of cilia and
flagella.
Centriole structure
Cilia and flagella
• Cilia (small and numerous) and flagella
(large and single) have a 9 + 2 pattern
of microtubules and are involved in cell
movement.
• Cilia and flagella move when the
microtubule doublets slide past one
another.
• Each cilium and flagellum has a basal
body at its base.
Structure of a flagellum or cilium
Prokaryotic Cells
• Prokaryotic cells include the bacteria and
archaea.
•
•
•
•
•
•
•
Bacterial cells have these constant features:
Outer Boundary: Cell wall
Plasma membrane
Cytoplasm:
Ribosomes
Thylakoids (Cyanobacteria)
Innumerable enzymes
Nucleoid:
Chromosome (DNA only)
• Bacterial cells may have plasmids,
small accessory rings of DNA.
• Some bacteria have a capsule or a
slime layer.
• Most bacteria have flagella.
• Some also have fimbriae that help
cells attach to surfaces.
• Bacteria have a great metabolic
diversity.
Evolution of the Eukaryotic Cell
• According to the endosymbiotic
hypothesis, eukaryotes arose from a
symbiotic relationship between various
prokaryotes.
- Heterotrophic bacteria became
mitochondria.
- Cyanobacteria became chloroplasts.
- Host cell was a large eukaryotic cell.
Evolution of the eukaryotic cell
Lab: The Cell
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
The three domains of life
Three-domain system of
classification
The Classification of Living Things
Domains (3: Archaea, Bacteria, Eukarya)
Kingdom
Phylum
Class
Order
Family
Genus
Species
Five-Kingdom System
• The five-kingdom system of classification is
based on structural differences and also on
modes of nutrition among the eukaryotes.
• The five kingdoms include:
• Monera (prokaryotes aka: bacteria)
• Eukaryotic kingdoms of Protista, Fungi,
Plantae, and Animalia (aka: plants and
animals).
The Classification of Living Things
3 Domains:
Archaea Bacteria
Monera
Eukarya
Protista
Plantae
5 Kingdoms
Fungi
Animalia
The Classification of Living Things
Archaea Bacteria
Monera
1. Oscillatoria
2. Gleocapsa
Eukarya
Protista
Plantae
1. Euglena
1. Elodea
2. Paramecium 2. Potato
Animalia
1. You!
Fungi
1. Yeast
Animal cell anatomy
Plant cell anatomy
Lab 4
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Diffusion and Osmosis
• Diffusion is the passive movement of
molecules from a higher to a lower
concentration until equilibrium is
reached.
• Gases move through plasma
membranes by diffusion.
Process of diffusion
Gas exchange in lungs by diffusion
Osmosis
• The diffusion of water across a
differentially permeable membrane due to
concentration differences is called
osmosis.
• Diffusion always occurs from higher to
lower concentration.
• Water enters cells due to osmotic pressure
within cells.
Osmosis demonstration
Osmosis in cells
• A solution contains a solute (solid)
and a solvent (liquid).
• Cells are normally isotonic to their
surroundings, and the solute
concentration is the same inside and
out of the cell.
• “Iso” means the same as, and
“tonocity” refers to the strength of the
solution.
Osmosis in plant and animal cells
• Hypotonic solutions cause cells to
swell and possibly burst.
• “Hypo” means less than.
• Animal cells undergo lysis in
hypotonic solution.
• Increased turgor pressure occurs in
plant cells in hypotonic solutions.
• Plant cells do not burst because they
have a cell wall.
• Hypertonic solutions cause cells to
lose water.
• “Hyper” means more than; hypertonic
solutions contain more solute.
• Animal cells undergo crenation
(shrivel) in hypertonic solutions.
• Plant cells undergo plasmolysis, the
shrinking of the cytoplasm.