Cell structures, cell theory, biological diversity

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GOOD
AFTERNOON
CELL BIOLOGISTS!

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MY TOPICS:MY TOPICS:
CELL STRUCTURES AND CELL
THEORY
INTRODUCTION TO BIOLOGICAL
DIVERSITY
INTRODUCTION TO BIOLOGICAL
DIVERSITY

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Factories of Life
CELLS
Basic and smallest units of life

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TYPES OF CELL
PROKARYOTIC CELL vs EUKARYOTIC CELL

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Comparison of Prokaryotic and Eukaryotic Cells
Prokaryotes Eukaryotes
Organisms Monera, Eubacteria,
Archaebacteria
Protists, Fungi, Plants,
and Animals
Nucleus No membrane bound
nucleus
Membrane bound
nucleus
Level of
Organization
Single-celled Single-celled (protists
mostly) or multicellular
usually with tissues
and organs
Typical cell size Small (0.5-100 µm) Large (10-150 µm)
Cell Wall Almost have cell wall
made of
peptidoglycan
(Thickness depends
on whether gram
positive or gram
negative
Cell wall, if present,
made of cellulose
(chitin in fungi)

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Organelles Usually none Many different ones
with specialized
functions
Metabolism Anaerobic and
aerobic
Mostly aerobic
Genetic
Material
Single circular
double stranded DNA
Complex chromosomes
usually in pairs; each
with a single double
stranded DNA
molecule and
associated proteins
contained in a nucleusMode of
division
Binary fission mostly,
budding
Mitosis and meiosis
followed by
cytokinesis

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Others Have pili, fimbriae,
and
flagella
Have cilia and flagella
Have mucilaginous
capsule
none

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Basic Structure of a Cell
plant cell animal cell

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plant cell

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animal cell

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Different kinds of plantDifferent kinds of plant
cellscells
Onion Epidermal Cells
Root Hair Cell
root hair
Guard Cells

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Different kinds of animalDifferent kinds of animal
cellscells
white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium

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Eukaryotic Cell
Contain 3 basic cell
structures:
• Nucleus
• Cell Membrane
• Cytoplasm with
organelles

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Parts of CellsParts of Cells
1. Plasma Membrane/Cell Membrane
copyright cmassengale
-is a continuous double-layered
(bilayer) membrane enclosing the cell
-is selectively/differentially permeable/
semi-permeable.

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Functions:
-regulates material moving into and out
of the cell, and from one part of the
cell to another.
-serves as a boundary between the
cell and its external environment.
-separates various organelles within
the cell.
-maintains cellular homeostasis.

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Functions:
-serves a site for receptors containing
specific cell identification markers that
differentiate one cell type from another.

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2. Cell Wall (Dead layer)
is a semirigid structure found outside the
plasma membrane of plants, fungi, and
some protists
-is made up primarily of polysaccharides
(cellulose) while fungi cell walls contain chitin.
-provides support for the cell. Limits the cell’s
volume; serves as “skeleton” of the plants.
-may serve to restrict the flow of water into
and out of the cell

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3. Mitochondrion (pl. mitochondria)
-is a small bag with a larger bag inside that is
folded back on itself forming series of
projections called CRISTAE (sing crista).
-a site for aerobic cellular
respiration
-a power house of the cell;
power generator; energy
converter

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3. Mitochondrion (pl. mitochondria)
-helps regulate the self-destruction of cells
(apoptosis).
-is also necessary for the production of
substances such as cholesterol and heme

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4. Plastid
-an organelle associated primarily with
the storage or manufacturer of
carbohydrates.

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KINDS:
1. Chloroplast
-contains the green pigment chlorophyll
- membranous saclike organelle found
only in plants.
-site for photosynthesis or food
production.

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Parts:
1. Stroma
- colorless fluid matrix that contains
enzymes which helps in carbon
fixation, carbohydrate synthesis and
other photosynthethic reactions
2. Granum
- A stack coin shaped double
membranes called THYLAKOIDS
contain chlorophyll.

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KINDS:
2. Chromoplast – colored plastid
*carotene/carotenoids –
orange pigment
- a plastid containing pigments other
than chlorophyll
*rheodoplast – red pigment
*xantophyll – yellow pigment
*fucoxanthin – brown pigment

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KINDS:
3. Leucoplast– colorless plastid
3.1 amyloplast -synthesizes starches
- serves as food storehouses
3.2 elaioplast -synthesizes oil
How Cells Obtain Energy - YouTube.flv

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5. Ribosome
-non-membranous dotlike structure
composed of ribosomal RNA(tRNA) and
proteins.
Can be attached to
Rough ER
OR
Be free
(unattached) in
the cytoplasm

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RibosomesRibosomes
UnitUnit
MembraneMembrane
VesiclesVesicles
formingforming
6. Endoplasmic Reticulum (ER)

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-is a network of flattened sacs, tubules and vesicles that
form channels throughout the cytoplasm.
- connects to nuclear envelope & cell membrane
storage and internal transport system

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-serves as a storage unit for enzymes and
other proteins
-serves as a point for attachment of
ribosomes.

Types of ER
1. Smooth ER
• Many metabolic processes
– synthesis
•synthesizes lipids
– oils, phospholipids, steroids & sex hormones
– hydrolysis
•hydrolyzes glycogen into
glucose
– in liver
•detoxifies drugs & poisons
– in liver
– ex. alcohol & barbiturates

2. Rough ER
• Membrane production
• Produces proteins in sacks called CISTERNAE
for export out of cell
– protein secreting cells
– package into transport vesicles for export

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7. Golgi Apparatus/Dictyosome

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-a term applied collectively to all Golgi
Bodies/Complex.
-a flattened, layered, roundish, sac-like
organelle that looks like a stack of
pancakes (called CISTERNAE) and is
located near the nucleus.
-collecting, sorting, packaging, and delivery
center
-”package counter of the cell”

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-packages proteins and carbohydrates into
membrane bound for export from the cell.
-transports mucus, carbohydrates,
glycoproteins, insulin, and enzymes to the
outside of the cell.
-a site where enzymes are converted from
their inactive to their active forms and
package in membranous sacs.

Vesicle transport
vesicle
budding
from rough
ER
fusion
of vesicle
with Golgi
apparatus
migrating
transport
vesicle
protein
ribosome

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8. Lysosome “The Cleanup Crew of the Cell”
“Cell’s Waste Disposal System”
-is a single membrane bound spherical
organelle that contains enzymes called
ACID HYDROLASE that accelerate the
breakdown of proteins, polysaccharides,
nucleic acids, and lipids.
-transport enzymes from ER to Golgi
apparatus.
-suicidal sac/bag of the cell

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8. Lysosome
-destroys microorganisms and other foreign
bodies taken in by the cell through its
membrane

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8. Lysosome
(a) Phagocytosis: lysosome digesting food
1 µm
Lysosome contains
active hydrolytic
enzymes
Food vacuole
fuses with
lysosome
Hydrolytic
enzymes digest
food particles
Digestion
Food vacuole
Plasma membrane
Lysosome
Digestive
enzymes
Lysosome
Nucleus
-destroys old cells

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9. Vacuole “storage tank of the cell”
-fluid-filled cavity surrounded
by membrane that stores large
amount of chemical that are
poisonous or distasteful to
herbivores
-provides the turgor, or
stiffness, of the cell which in
turn provide support for the
structure of nonwoody plants.
-Contains water, cell sap, sugars,
proteins, minerals, wastes, & pigments

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10. Cytoskeleton
-framework of the cell
-set of fibers that contributes to the
cells’ shape and supports the internal
system connecting the various organelles
and cellular components.

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10. Cytoskeleton
Components:
1. Microtubules – are long, hollow,
slender, cylindrical structures which
are made up of subunits of protein
called TUBULIN.
- function in the movement of
organelles and in chromosome
movement during division of cell
nucleus.

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10. Cytoskeleton
Components:
1. Microtubules
*CENTRIOLES/CENTROSOMES
- nine sets of three fused
microtubules that radiate from the
center like the spokes of a wheel
- help organize the microtubules in cells
about to undergo division

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10. Cytoskeleton
Components:
2. Microfilaments – are solid strings of
protein ACTIN molecules; may be single, or
in bundles and networks
-help the cell to contract and many
types of motion (movement of organelles
and particles and in pinching movements of
daughter cells after nuclear division.

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10. Cytoskeleton
Components:
3. Intermediate Filaments – made of group
of protein fibers that help to maintain the
shape of the cells, promote mechanical
activities within the cytoplasm, and
maintain the position of the nucleus in the
cell.

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11. Nucleus
-spherically shaped structure that is
located near the center of the cell.
- the control and information center of the cell
-directs the chemical reactions that occur in
cells by transcribing genetic information in the
DNA into RNA, which then translates the
specific information into proteins that determine
the cell’s specific activities.
-also stores genetic information and transfer it
during cell division from one cell to the next,
and from one generation to the next.

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11. Nucleus
1. Nuclear membrane/nuclear envelope
- double membrane that surrounds the nucleus
and separates the nucleus from the cytoplasm
and is continuous with the ER at a number of
points.
-contains pores, or small openings, that allow
certain molecules to move in and out of the
nucleus.
Structures:

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11. Nucleus
2. Chromatin2. Chromatin
– long, fine, tangled threads of DNA in
association with proteins in the nucleoplasm and
visible during nuclear division as
CHROMOSOMES---bearers of hereditary
information in segments of DNA called GENES.

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11. Nucleus
3.Nucleolus3.Nucleolus
-non-membrane bound dense, roughly spherical
body in the nucleoplasm.
- Cell may haveCell may have 1 to 31 to 3 nucleolinucleoli
- is the site of ribosome manufacture
- preassembly point for ribosomes
Three-dimensional views of the
ribosome, showing rRNA in dark blue
(small subunit) and dark red (large
subunit). Lighter colors represent
ribosomal proteins.

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12. Cilia and Flagella

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12. Cilia and Flagella
• Tubular extensions of plasma
membrane
• Movement of fluid, or locomotion
• Two functionally different types
– Cilia: numerous, paddle-like,
synchronized
– Flagella: longer, fewer, more whip-like
• Filled with microtubules
– 9 pairs in periphery; 2 singlets in
center
– “9+2” arrangement (for eukaryotes)

In 1590: HANS AND ZACHARIAS
JANSSEN
Dutch spectacle-makers
-invented the
first compound
microscope

In 1665: ROBERT HOOKE
(English Scientist)
-examined a thin
slice of cork of oak
tree and saw many
tiny compartments
(were only cell walls of
dead cells) and called
them CELLS.

In 1668: FRANCISCO REDI
(Italian Physician)
-disproved the theory of
spontaneous generation.

In 1674: ANTON van
LEEUWENHOEK (Dutch
Naturalist)
-observed red blood
cells, sperms, and single
celled organisms called
“animalcules” in pond
water.

In 1809: JEAN BAPTISTE LA
MARCK (French)
-said that Hooke’s cells
were not empty but were
filled with complex fluids.
-concluded that “No body
can have life if its
constituents parts are not
cellular tissue or are not
formed by cellular tissue.”

In 1824: RENE DUTROCHET
(French)
-stressed that all
animals and plant tissues
are composed of cells of
various kinds.
-concluded that cell
is truly the fundamental
part of the living
organism.

In 1831: ROBERT BROWN
(English Botanist)
-discovered that all cells
contain large central body
called NUCLEUS.

In 1835: FELIX DUJARDIN (France)
-observed material
inside the cell called
SARCODE(fleshy part).

In 1838: MATTHIAS SCHLEIDEN
(German Biologist)
-stated that all plantsall plants are
composed of cells.
-discovered the nucleolusnucleolus

In 1839: JAN EVANGELISTA
PURKINJE (Bohemian)
-gave the name
PROTOPLASMPROTOPLASM to the complex
material inside the cell.

In 1839: THEODORE SCHWANN
(German Zoologist)
-stated that all animals are
composed of cells.

In 1855: RUDOLPH VIRCHOW
(German Biologist)
-theorized that all living
things come from pre-existing
cells.
““omnis cellula e cellula”omnis cellula e cellula”

1. All living things are made up of one or more cells and
cell products.
2. All living cells come from pre-existing
cells.
3. Cells are the basic units of structure, function, and
organization in organisms.
Cell TheoryCell Theory

In 1856: Gregor Johann Mendel
(Austrian monk)
- described how traits
were inherited by his
experiment with peas.
-derived certain basic
laws of heredity

In 1859: Charles Darwin
(English biologist)
- publishes the Origin ofOrigin of
SpeciesSpecies that explains
heredity and variations in
different species.

In 1882: WALTHER FLEMING
(German biologist)
- found rods in a cell. He
called these rods as
chromosomes.

In 1903: WALTER SUTTON
(German biologist)
- demonstrated that
chromosomes exist in
structurally similar
pairs.
- proved that egg and
sperm cells only have
one out of each set
of chromosomes.

In 1903: THOMAS HUNT MORGAN
(American biologist)
- showed that genes could
be found on
chromosomes.
- discovered the X and Y
chromosomes,

In 1916: GEORGE BEADLE
and
EDWARD TATUM
(American biologists)
- discovered that genes
control things like the
production of enzymes.

In 1944: OSWALD AVERY
(American biologist)
- announced that DNA is
the only substance
responsible for heredity.

In 1952: FRANCIS CRICK
and
JAMES WATSON
(American biologists)
- made a model of the
DNA molecule.
- proved that genes
are responsible for
heredity.

4. Energy flow occurs within cells.
5. Cell contain hereditary information (DNA)which is
passed on from cell to cell during cell division
6. All cells are basically the same in chemical composition
in organisms of similar species
The modern version of the CellThe modern version of the Cell
Theory includes the ideas that:Theory includes the ideas that:
7. The activity of an organism depends on the total activity
of independent cells.

BIOBIODIVERSITY
 It was first coined by the entomologist
Edward O. Wilson in 1986.
 is the heritage of million of years of evolution.

BIOBIODIVERSITY
 is dynamic

BIOBIODIVERSITY
 is the measure of variety and variability
among living organisms and the ecological
complexes in they occur.
Variety - the number of
different types.
Quantity - the number or
total biomass of any one
type.
Distribution - the extent
and nature of geographic
spread of different types.

BIOBIODIVERSITY
 is the totality of genes, species, and
ecosystems in a region.
is the sum of life on Earth.

LEVELS OF BIOBIODIVERSITY
1. GENETIC DIVERSITY
- is the combination of
different genes found within a
population of a single species,
and the pattern of variation
found within different
populations of the same species.

2. SPECIES DIVERSITY
- is the variety and abundance of
different types of organisms which
inhabit an area.
-

3. ECOSYSTEM DIVERSITY
- encompasses the variety of
habitats that occur within a
region.

MEASURING BIOBIODIVERSITY
1. NUMBERS/RICHNESS
- the quantities of how many
species are found in an
area, or how many alleles a
species has for a single
locus, or how many
functional groups or
taxonomic groups higher
than species are present in
an ecosystem.
Area 1

1. NUMBERS/RICHNESS
-can be expressed as the
number of species found per
unit area, per unit mass, or per
number of individuals
identified.
Area 1

2. EVENNESS
-refers to how close in
numbers each species in an
environment are.
-measures to what extent
individuals are evenly
distributed among species
Area 2

3. DIFFERENCE
-refers to the number of
different species in a
particular area
Area 3

Values of biodiversity
Values of
biodiversity
Ecological
values
Economic
values
Cultural
values

Significance of biodiversity
Regulation of climate and biogeochemical cycles,
Hydrological functions,
Soil formation and protection,
Crop pollination,
Pest control,
Recreation and ecotourism ,
Ecological resilience,
Wildlife habitat and diversity,
Medicinal resources,
Fuel resources,
Wood products and ornamental plants,
Food, and
Future resources

Main Causes of Biodiversity Loss
 habitat change/loss/fragmentation

Fragmentation most easily observed in forest
habitat is caused by human activities. Anywhere that
humans transformations cut up continuous habitat.

 climate change

 invasive species

 overexploitation
Over-hunting – unregulated hunting
Over harvesting
Over-collecting

 pollution
 Acid deposition
Global warming
Toxic chemicals
Plastics

Biodiversity is the greatest
treasure we have... Its
diminishment is to be prevented at
all cost.
- Thomas Eisner

Cell structures, cell theory, biological diversity

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