Biology the Science of
Life
Cells: 2.1.1. 2.1.2,
2.3.4,2.1.8-2.1.10
Classification: 5.5.1, 5.5.2,
5.5.5
Text: Ch. 1 (3-13), Ch. 23
(468-472)
Syllabus statements
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2.1.1 – Outline the cell theory
2.2.2 – Discuss the evidence for cell theory
2.3.4 – Compare prokaryotic and eukaryotic cells
2.1.8 – Explain that cells in multicellular
organisms differentiate to carry out specialized
functions by expressing some of their genes but
not others
2.1.9 – State that stem cells retain the capacity
to divide and have the ability to differentiate
along different pathways
2.1.10 – Outline one therapeutic use of stem cells
Syllabus statements
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5.5.1 –Outline the binomial system of
nomenclature
5.5.2 – List the seven levels in the
hierarchy of taxa – kingdom, phylum,
class, order, family, genus, species –
using an example from two different
kingdoms for each level
5.5.5 – Apply and/or design a key for a
group of up to eight organisms
Study of Life
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What is alive?
• 6 shared characteristics
• Order, Response, Growth and
Development, Use of Energy,
Homeostasis, Adaptation
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How do we organize living things?
• Hierarchy of Life
Hierarchy of Life
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Atoms, molecules,
cellular organelles,
cells, tissues,
organs, organ
systems, organism
The 6 characteristics of life
1. Order
All living things made of one or more cells
Cells are the basic unit of life
2. Response
Exhibit sensitivity
Response to stimuli = pupil dilation, plants grow to light, blink
3. Growth Development & Reproduction
DNA common hereditary molecule
4. Energy Utilization
Uptake and Transformation
Photosynthesis and Respiration (Green Plants & All organisms)
5. Homeostasis
Maintaining constant internal conditions (Temp, Water balance, O2/CO2 )
Behaviorally or Biologically
6. Adaptation
Change in response to Environmental Conditions
Desert organsims minimize water loss
Energy
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Photosynthesis (Green Plants)
sunlight +water + carbon dioxide  oxygen + sugars
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Respiration (All living things)
oxygen + sugars  ATP +water + carbon dioxide
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ATP is molecular energy storage
Cells are the basic unit of Life!!
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Cells 0-100 millionths of a meter
(10-100 micrometers mm)
Not observed until we had
technology to do so
Microscopes invented in mid 17th
century
First light microscopes then electron
microscopes more recently
Timeline of Cell Discovery
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1590 – Zachariah
Jansen
-Invented
compound (2 lens)
microscopes
Timeline of Cell Discovery
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1665 – Robert
Hooke
-Examined cork
-First to see dead
cells, called cellulae
(small rooms) for little
compartments
Timeline of Cell Discovery
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1650-1700 – Anton
von Leewoenhoek
-Dutch botanist
used lens x200, x300
-First to examine
living cells, pond water,
sperm, blood
-Called animalcules
(little animals) in p.w.
-single celled
organisms
Timeline of Cell Discovery
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1707-1778
Carolus Linnaeus
-swedish physician
and botanist
-founder of taxonomy
-developed
classification system
for all living organisms
Timeline of Cell Discovery
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1838 – Matthias
Schleiden
-German botanist
-cell theory
-plant observations
*all plants made of
cells
Timeline of Cell Discovery
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1839 – Theodor
Schwann
-German biologist
-Cell Theory
-All animals are
made of cells
History continued
Purkinje: fibers that transmit
stimulus to myocardial cells of
ventricles of heart bear his name;
coined term “protoplasm” for the
living content of cells.
1855: Rudolf Virchow: studied
pathogenic organisms and showed
that “omnis cellula e cellula” – all
cells arise from preexisting cells (by
cell division).
1840
Timeline of Cell Discovery
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1940’s – Advent of
the Electron
Microscope
TEM – transmission
of electrons through
specimen
SEM – scanning of
surface with electron
Electron Micrographs
Cell Theory
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1.
2.
3.
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Three principles based on different
studies
All organisms made of cells
Cells are the basic unit of life
Cells come from other preexisting
cells
BUT… All cells aren’t created equal
The two major types of cells
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1.
2.
3.
4.
Prokaryotes
(All are
Prokaryotae)
Very small (110um)
No nucleus
(nucleoid – DNA
in central area)
No membrane
bound organelles
Have cell walls
Eukaryotes
(all other
kingdoms)
Size 10-100 um
1. DNA in
chromosomes in
nucleus
2.
Many M.B.O.
3.
Plants & some
fungi have cell
walls
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To have different cells do different
things you need differentiation
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So cells develop along different pathways
or differentiate
This means different cells express
different genes
Remember that every cell in an organism
has all the same DNA, only some cells
express different genes within that
genome
Once the developmental pathway of a cell
is started then it is usually fixed
So which cells can differentiate?
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Stem cells – can self renew and
differentiate
Human embryos are almost all stem
cells
Some still found in different human
tissues like skin, liver bone marrow
Those only used for limited repair
Therapeutic use of stem cells
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Area of rapid development – many uses
exist
Cord blood from umbilical cord contains
hematopoietic stem cells – can become
any blood cell type
Test the blood and remaining fluid
Used to treat some leukemias – chemo to
kill the cells that over produce white blood
cells then introduce cord blood to blood
stream of patient
Stem cells establish themselves in the
marrow and replace defective cells
Possible fates of cord blood stem
cells
Classifying all this life
Diversity of Cells Diversity of Life
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Currently 1.5x106 identified species
Study and grouping of this diversity
is the science of taxonomy
Taxonomic hierarchy – KPCOFGS
Many systems – Ours 5 kingdoms
-know examples of each
5 kingdom system: Prokaryotae
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A.
B.
Monera (bacteria)
Hetero & Autotrophs
Archaebacteria
-primitive,
extremophiles (halo-,
thermo-), don’t need
O2
Eubacteria
-most of the bacteria
-some parasites but
all modes of nutrition
40,000x magnification
5 kingdom system: Protoctista
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Protists
-eukaryotes most
unicellular
-hetero &
autotrophs
-algae, amoeba,
ciliates, diatoms
5 kingdom system: Fungi
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Eukaryotes – most
multicellular
Yeast, mushrooms,
molds
Heterotrohpic –
acquire food by
absorbtion
If cell wall is
present, made of
chitin
5 kingdom system: Plantae
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Multicellular,
Autotrophic
(Photosynthesis),
Eukaryotes
Cells have a cell
wall made of
cellulose
Mosses, ferns,
conifers, flowering
plants
5 kingdom system: Animalia
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Multicellular,
Heterotrophic,
Eukaryotes
Lack cell wall
From Largest grouping to Smallest
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Species – A population of organisms
who have the potential to interbreed
and produce fertile, viable offspring
Largest grouping of a population
which can exchange genetic material
but genetically isolated from other
groups
Classifying Organisms
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Systematics – a classification process
for studying biodiversity
Taxonomy – branch of biology
concerned with naming and
classifying organisms
Group species into larger categories
from genus up to kingdom
The Importance of Classification
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Common names useless –
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Shows evolutionary relationships –
panther,
puma, mountian lion, cougar = Felis concolor
bears, raccoons sloths (p 47)
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Enables predictions of characteristics
shared by members of group – e.g.
new primate discovered expect diagnostic char.
The Importance of Classification II
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ID of organisms by organizing
ecological, anatomical, physiological,
molecular (DNA & protein
specifically) data
1. Proteins: Cytochrome C; has 104
Amino acids found in mitochondria
2. Consider differences in amino acids –
human vs chimps = 0, human vs. dogs = 13,
vs. snakes = 20, vs tuna = 33
Binomial Nomenclature System
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Created by C. Linneaus
Each species has 2 part Latin name
Genus species (computer)
Genus species (handwritten)
E.g.
Homo sapiens = humans
Felis sylvestris = house cat
Ranunculus acris = buttercup
Remember: KPCOFGS
(memorize the following examples)
Levels
Kingdom
Domestic
Cat
Animalia
Common
Buttercup
Plantae
Human
Animalia
Phylum
Chordata
Anthophyta
Chordata
Class
Mammalia
Dicotyledons
Mammalia
Order
Carnivora
Ranunculales
Primates
Family
Felidae
Ranunculacae
Hominidae
Genus
Felis
Ranunculus
Homo
Species
sylvestris
acris
sapiens
Remember: KPCOFGS
(memorize the following examples)
Levels
Kingdom
Phylum
Class
Order
Family
Genus
Species
Domestic
Cat
Common
Buttercup
Human
Review Points
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6 characteristics of Life
Levels of the hierarchy of Life
3 principles of Cell theory
Difference between prokaryotes and
eukaryotes
5 kingdoms and their characteristics
Kingdom, Phylum, Class, Order, Family,
Genus, species