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Chapter 4
Functional
Anatomy of
Prokaryotic and
Eukaryotic Cells
Copyright © 2010 Pearson Education, Inc.
Lectures prepared by Christine L. Case
Prokaryotic and Eukaryotic Cells
 Prokaryote comes from the Greek words for
prenucleus. Bacteria and Archaea are the
Prokaryotes
 Eukaryote comes from the Greek words for
true nucleus. All other cellular organisms are
Eukaryotes.
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Fungi (molds, yeast)
Protista (unicellular algae and protozoans)
Plants
Animals
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Prokaryote
 One circular chromosome,
not enclosed in a
membrane-found in the
Nucleoid region of the cell
 Only non-histone proteins
with the DNA
 No membrane-enclosed
organelles
 Peptidoglycan cell walls if
Bacteria
 Pseudomurein cell walls if
Archaea
 Binary fission form of cell
division
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Eukaryote
 Multiple chromosomes,
in nuclear membraneThe Nucleus.
-Histones and
nonhistones with DNA
 Membrane-enclosed
organelles
 Simple, polysaccharide
cell walls
 Mitotic form of cell
division with a ‘spindle’
Comparing Sizes: Animation comparing viruses, bacteria,
eukaryotic cells http://www.cellsalive.com/howbig.htm
Eukaryotic cells are highly compartmentalized. A large
surface-to-volume ratio, as seen in smaller prokaryotic
cells, means that nutrients can easily and rapidly reach
any part of the cells interior. However, in the larger
eukaryotic cell, the limited surface area when compared to
its volume means nutrients cannot rapidly diffuse to all
interior parts of the cell. That is why eukaryotic cells
require a variety of specialized internal organelles to
transport chemicals throughout the cell and carry out
life functions (most of the things needed for a particular
function are kept together in membranous structures
rather than free-floating).
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Basic Shapes
 Bacillus (rod-shaped)
 Coccus (spherical)
 Spiral
 Spirillum
 Vibrio
 Spirochete
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Figures 4.1a, 4.2a, 4.2d, 4.4a, 4.4b, 4.4c
Unusually Shaped Bacteria
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Figure 4.5a
Unusually Shaped Bacteria
Fig. 4.5b p. 79
Archaea,not Bacterium
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Figure 4.5b
Arrangements
 Pairs: Diplococci,
diplobacilli
 Clusters:
Staphylococci
 Chains:
Streptococci,
streptobacilli
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Figures 4.1a, 4.1d, 4.2b, 4.2c
The Structure of a Prokaryotic Cell
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Figure 4.6
Glycocalyx
 Outside cell wall
 Usually sticky (biofilms)
 Capsule: neatly
organized
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 Slime layer: unorganized
and loose
 Extracellular
polysaccharide allows
cell to attach
 Capsules prevent
phagocytosis
 Capsules were
instrumental in
determining that DNA
was the genetic material
(Fig. 8.24 p. 235)
Figure 24.12
Transformation:
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Griffith discovers Transformation (1928)
 While working with encapsulated S strains and
unencapsulated R strains of Streptococcus
pneumonia (pneumococcus), Griffith observed that
when heat-killed S forms and living R forms were
injected into mice, the mice died. When he isolated
living bacteria from the dead mice, they had a
capsule. The R strain had been transformed into an
S strain! Transformation is a common procedure in
today's genetic engineering labs.
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Oswald Avery, Colin MacLeod, and Maclyn (1944)
determined that the ‘transforming’ (genetic/hereditary)
molecule was
.
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Arrangements of Bacterial Flagella
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Figure 4.7
Axial Filaments
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Also called endoflagella or
periplasmic flagella
In spirochetes only
The spirochetes are a … unique
group of bacteria. This phylum
contains not only many medically
important species such as
Treponema pallidum and Borrelia
burgdorferi but others live inside
arthropods such as termites and
some that are free-living and reside in
soil and water.
http://jb.asm.org/cgi/content/full/182/23/6698

Individual AF can be anchored at one
end or the other of a cell. Rotation
causes the cell to move.
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Figure 4.10a
Fimbriae and Pili: Made of a different protein (pilin)
than flagella and are shorter, thinner, straighter.
Fimbriae allow attachment: Important for some diseases (gonorrhea and
E.coli 0157:H7) and biofilms.
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Figure 4.11
The Cell Wall (Fig. 4.13 p. 86)
 Prevents osmotic lysis
 In bacteria:
 Made of peptidoglycan
 Gram Positive vs. Gram Negative Cell Walls
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Figure 4.6
Peptidoglycan in Gram Positive
Bacteria
 Linked by polypeptides
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Figure 4.13a
Gram Positive Cell Wall
Many layers of peptidoglycan
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Gram positive
Cell Wall
Gram negative
Cell Wall
 Thick peptidoglycan
 Teichoic acids
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Thin peptidoglycan
Outer membrane
Periplasmic space
No Teichoic acids
Figure 4.13b–c
Gram-Negative Cell Wall
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Figure 4.13c
Gram Negative Periplasm
 The space between the plasma membrane and the
outer membrane
 Gel-like fluid containing digestive enzymes and
transport proteins
 The periplasm also contains the one/few layer(s) of
peptidoglycan (bonded to lipoproteins in the outer
membrane)
 In Spirochetes, the axial filaments are found in the
periplasm
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Gram-Negative Outer Membrane
 Protection from lysozyme, some detergents,
phagocytes, complement (in blood-lyses cells and
promotes phagocytosis), and certain antibiotics
 Contains Lipopolysaccharide: Important parts of LPS
 O polysaccharide antigen can be used to distinguish
between serovars (strains) e.g., E. coli O157:H7
 Lipid A is an endotoxin (Released when the bacterium
dies- causes septic shock)
 Also contains Porins- Proteins that form channels
through the outer membrane for nutrient transport
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The Gram Stain
(a) Gram-Positive
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(b) Gram-Negative
Table 4.1
Gram-Positive
Cell Wall
Gram-Negative
Cell Wall
 2-ring basal body
(flagella)
 Disrupted by lysozyme
(destroys bonds
connecting NAG-NAM)
 Penicillin sensitive
 4-ring basal body (flagella)
 Endotoxin
 Tetracycline sensitive
(Penetrates the OM
better-interferes with
protein synthesis)
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Figure 4.13b–c
Atypical Cell Walls
 Acid-fast cell walls
 Difficult to stain, but carbolfuchsin and heat will stain it red
 Waxy lipid (mycolic acid) bound to peptidoglycan (if
mycolic acid removed, will be Gram +)
 Mycobacterium
(branching filaments)
 Tuberculosis
 Leprosy
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Figure 24.8
Atypical Cell Walls
 Mycoplasmas: smallest living organism that can
grow/reproduce outside another living cell
 Lack cell walls
 Sterols in plasma membrane believed to aid in preventing
lysis
 Archaea
 Wall-less or
 Walls containing pseudomurein (lack NAM and D-amino
acids)
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The Plasma Membrane
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Figure 4.14a
The Plasma Membrane Fig. 4.14 p. 90
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Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane
Proteins
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Figure 4.14b
Fluid Mosaic Model
 Membrane is as viscous as olive oil
 Proteins move to function
 Phospholipids rotate
and move laterally
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Figure 4.14b
The Plasma Membrane
 Selective permeability allows passage of some
molecules
 Enzymes for ATP production
 Photosynthetic pigments on foldings called
chromatophores or thylakoids
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Chromatophores
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Figure 4.15
The Plasma Membrane
 Damage to the membrane by alcohols, quaternary
ammonium (detergents), and polymyxin antibiotics
causes leakage of cell contents
ANIMATION Membrane Structure
ANIMATION Membrane Permeability
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Movement of Materials across
Membranes
 Simple diffusion:
Movement of a solute
from an area of high
concentration to an
area of low
concentration
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Figure 4.17a
Movement of Materials across
Membranes
 Facilitated diffusion: Solute combines with a
transporter protein in the membrane
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Figure 4.17b-c
Movement of Materials across
Membranes
 Osmosis: The movement of water across a
selectively permeable membrane from an area
of high water to an area of lower water
concentration
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Figure 4.18a
Movement of Materials across
Membranes
 Through lipid layer
 Aquaporins (water
channels)
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Figure 4.17d
The Principle of Osmosis Fig. 4.18 p. 93
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Figure 4.18c–e
Movement of Materials across
Membranes
 Active transport: Requires a transporter protein
and ATP
 Group translocation: Requires a transporter protein
and PEP
ANIMATION Active Transport: Types
ANIMATION Active Transport: Overview
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Archaeal vs. Bacterial/Eukaryal
Plasma Membranes
 Archaeal cell membranes are chemically different
from the membranes of all other living things.
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Cytoplasm
 The substance inside the plasma membrane
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Figure 4.6
The Nucleoid
 Bacterial chromosome
 Plasmids
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Figure 4.6
Ribosomes
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Figure 4.6
The Prokaryotic Ribosome
 Protein synthesis
 70S
 50S + 30S subunits
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Figure 4.19
Inclusions: Reserves deposits; help
maintain osmotic balance
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Metachromatic granules
Polysaccharide granules
Lipid inclusions
Sulfur granules
Carboxysomes
Gas vacuoles
 Magnetosomes
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 Phosphate reserves
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Energy reserves
Energy reserves
Energy reserves
Ribulose 1,5-diphosphate
carboxylase for CO2 fixation
 Protein-covered cylinders; allows
aquatic cells to have the correct
level of buoyancy needed to
receive the appropriate amount of
light/oxygen/nutrients
 Iron oxide
(destroys H2O2)
Magnetosomes
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Figure 4.20
Endospores
 Dormant
 Resistant to desiccation, hostile environments (cold,
heat, chemicals), lack of nutrients
 Mostly specific Gram + bacteria Bacillus (anthrax),
Clostridium (tetanus, botulism, gangrene)
 Sporulation: Endospore formation
 Germination: Return to vegetative state
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Endospores
Figure 4.21b
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Sporulation and Germination
Figure 4.21a
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The Eukaryotic Cell
Figure 4.22a
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Flagella and Cilia
Figure 4.23a-b
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The Cell Wall and Glycocalyx
 Cell wall
 Plants, algae, fungi
 Carbohydrates
 Cellulose, chitin, glucan, mannan
 Glycocalyx
 Carbohydrates extending from animal plasma membrane
 Bonded to proteins and lipids in membrane
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Q&A
 Penicillin was called a
“miracle drug” because
it doesn’t harm human
cells. Why doesn’t it?
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The Plasma Membrane
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Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane proteins
Sterols
Glycocalyx carbohydrates
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The Plasma Membrane
 Selective permeability allows passage of some
molecules
 Simple diffusion
 Facilitative diffusion
 Osmosis
 Active transport
 Endocytosis
 Phagocytosis: Pseudopods extend and engulf particles
 Pinocytosis: Membrane folds inward, bringing in fluid and
dissolved substances
 Exocytosis: reverse of endocytosis
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Cytoplasm
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Table 4.2
Cytoplasm
 Cytoplasm membrane: Substance inside plasma
and outside nucleus
 Cytosol: Fluid portion of cytoplasm
 Cytoskeleton: Microfilaments, intermediate
filaments, microtubules
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Ribosomes in Eukaryotes
 Protein synthesis
 80S
 Membrane-bound: Attached to ER
 Free: In cytoplasm
 70S
 In chloroplasts and mitochondria
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Organelles
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Nucleus: Contains chromosomes
ER: Transport network
Golgi complex: Membrane formation and secretion
Lysosome: Digestive enzymes
Vesicles:
Vacuole: Brings food into cells and provides support
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Organelles
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Mitochondrion: Cellular respiration
Chloroplast: Photosynthesis
Peroxisome: Oxidation of fatty acids; destroys H2O2
Centrosome: Consists of protein fibers and
centrioles (Utilized for cell division)
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The Eukaryotic Nucleus
Figure 4.24a–b
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Rough Endoplasmic Reticulum
Figure 4.25
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Micrograph of Endoplasmic Reticulum
Figure 4.25b
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Vesicles and Golgi Complex
Figure 4.26
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Lysosomes: Made in the Golgi body.
Contain digestive enzymes that degrade
waste, invaders (bacteria), damaged cells
and particles, larger molecules into needed
smaller molecules, etc.
Vacuoles: Storage (food, toxins, waste,
water)
Figure 4.22b
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Mitochondria
Figure 4.27
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Chloroplasts
Figure 4.28
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Peroxisome: Enzymes which function in
normal metabolism and degrade toxins.
Contain catalase to decompose H2O2
(Produced as a by-product during the
metabolic reactions in the peroxisome).
Centrosome: Produce microtubules needed
for cell division and the cytoskeleton
Figure 4.22b
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Endosymbiotic Theory
Figure 10.2
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Endosymbiotic Theory
 What are the fine extensions on this protozoan?
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Endosymbiotic Theory
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