Download 2013/2/18 1 Chapter 4

2013/2/18
Chapter 4
Functional
Anatomy of
Prokaryotic and
Eukaryotic Cells
© 2013 Pearson Education, Inc.
Copyright © 2013 Pearson Education, Inc.
Lectures prepared by Christine L. Case
Lectures prepared by Christine L. Case
© 2013 Pearson Education, Inc.
Prokaryotic and Eukaryotic Cells
Prokaryote
Eukaryote
 Prokaryote comes from the Greek words for
prenucleus.
 Eukaryote comes from the Greek words for
true nucleus.
 One circular
chromosome, not in a
membrane
 No histones
 No organelles
 Bacteria: peptidoglycan
cell walls
 Archaea: pseudomurein
cell walls
 Binary fission
 Paired chromosomes,
in nuclear membrane
 Histones
 Organelles
 Polysaccharide cell
walls
 Mitotic spindle
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Prokaryotic Cells: Shapes
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Figure 4.9b Flagella and bacterial motility.
 Average size: 0.2–1.0 µm  2–8 µm
 Most bacteria are monomorphic
 A few are pleomorphic
A Proteus cell in the swarming stage may have
more than 1000 peritrichous flagella.
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Basic Shapes
 Bacillus (rod-shaped)
 Coccus (spherical)
 Spiral
Figure 4.1a Arrangements of cocci.
Plane of
division
Diplococci
 Spirillum
 Vibrio
 Spirochete
Streptococci
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Figure 4.4 Spiral bacteria.
Figure 4.2ad Bacilli.
Vibrio
Single bacillus
Spirillum
Coccobacillus
Spirochete
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Bacillus or Bacillus
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Figure 4.3 A double-stranded helix formed by Bacillus subtilis.
 Scientific name: Bacillus
 Shape: bacillus
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Figure 4.5a Star-shaped and rectangular prokaryotes.
Star-shaped bacteria
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Figure 4.5b Star-shaped and rectangular prokaryotes.
Rectangular bacteria
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Arrangements
Figure 4.1ad Arrangements of cocci.
Plane of
division
 Pairs: diplococci, diplobacilli
Diplococci
 Clusters: staphylococci
 Chains:
Ch i
streptococci,
t t
i streptobacilli
t t b illi
Streptococci
Staphylococci
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Figure 4.2b-c Bacilli.
Figure 4.6 The Structure of a Prokaryotic Cell.
Pilus
Cell wall
The drawing below and the
micrograph at right show a bacterium Capsule
sectioned lengthwise to reveal the
Although the nucleoid appears
internal composition. Not all bacteria
split in the photomicrograph,
have all the structures shown; only
the thinness of the “slice” does
structures labeled in red are found in
not convey theobject’s depth.
all bacteria.
Cytoplasm
Diplobacilli
70S Ribosomes
Plasma membrane
Nucleoid containing DNA
Inclusions
Plasmid
Fimbriae
Capsule
Cell wall
Streptobacilli
Plasma
membrane
Flagella
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.
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Figure 24.12 Streptococcus pneumoniae, the cause of pneumococcal pneumonia.
Glycocalyx






Outside cell wall
Usually sticky
Capsule: neatly organized
Slime layer: unorganized and loose
E t
Extracellular
ll l polysaccharide
l
h id allows
ll
cellll tto attach
tt h
Capsules prevent phagocytosis
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© 2013 Pearson Education, Inc.
Figure 4.8b The structure of a prokaryotic flagellum.
Flagella




Outside cell wall
Made of chains of flagellin
Attached to a protein hook
Anchored to the wall and membrane by the
basal body
Flagellum
Grampositive
Filament
Cell wall
Hook
Basal body
Peptidoglycan
Plasma
membrane
Cytoplasm
Parts and attachment of a flagellum of a
gram-positive bacterium
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Figure 4.8a The structure of a prokaryotic flagellum.
Figure 4.7 Arrangements of bacterial flagella.
Flagellum
Gramnegative
Filament
Hook
Basal body
Cell wall
Peritrichous
Monotrichous and polar
Peptidoglycan
Outer
membrane
Plasma
membrane
Cytoplasm
Lophotrichous and polar
Amphitrichous and polar
Parts and attachment of a flagellum of a
gram-negative bacterium
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Figure 4.9a Flagella and bacterial motility.
Motile Cells
Run
 Rotate flagella to run or tumble
 Move toward or away from stimuli (taxis)
 Flagella proteins are H antigens
(e.g., E. coli O157:H7)
Tumble
Run
Tumble
Run
Tumble
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Figure 4.10a Axial filaments.
Axial Filaments




A bacterium running and tumbling. Notice that the
direction of flagellar rotation (blue arrows) determines
which of these movements occurs. Gray arrows indicate
direction of movement of the microbe.
Also called endoflagella
In spirochetes
Anchored at one end of a cell
Rotation causes cell to move
A photomicrograph of the spirochete
Leptospira, showing an axial filament
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Figure 4.10b Axial filaments.
Fimbriae and Pili
 Fimbriae allow attachment
Outer sheath
Cell wall
Axial filament
A diagram of axial filaments wrapping around
part of a spirochete (see Figure 11.26a for a
cross section of axial filaments)
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Figure 4.11 Fimbriae.
Fimbriae and Pili
 Pili
 Facilitate transfer of DNA from one cell to another
 Gliding motility
 Twitching motility
Fimbriae
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The Cell Wall
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Figure 4.6 The Structure of a Prokaryotic Cell (Part 1 of 2).
Pilus
 Prevents osmotic lysis
 Made of peptidoglycan (in bacteria)
Cytoplasm
70S Ribosomes
Plasma membrane
Nucleoid containing DNA
Inclusions
Plasmid
Fimbriae
Capsule
Cell wall
Plasma
membrane
Flagella
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Peptidoglycan
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Figure 4.12 N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) joined as in a peptidoglycan.
N-acetylglucosamine
(NAG)
N-acetylmuramic acid (NAM)
 Polymer of disaccharide:
 N-acetylglucosamine (NAG)
 N-acetylmuramic acid (NAM)
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Peptidoglycan in Gram-Positive
Bacteria
Figure 4.13a Bacterial cell walls.
Tetrapeptide side chain
N-acetylglucosamine (NAG)
N-acetylmuramic acid (NAM)
Side-chain amino acid
Cross-bridge amino acid
 Linked by polypeptides
Peptide cross-bridge
NAM
Peptide
bond
Carbohydrate
“backbone”
Structure of peptidoglycan in
gram-positive bacteria
.
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Gram-Positive
Cell Wall
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Gram-Negative
Cell Wall
Figure 4.13b-c Bacterial cell walls.
Peptidoglycan
Wall teichoic acid
Lipoteichoic
acid
Cell wall
 Thick peptidoglycan
 Teichoic acids
 Thin peptidoglycan
 Outer membrane
 Periplasmic space
Plasma
membrane
Protein
O polysaccharide
Core polysaccharide
C
l
h id
Gram-positive cell wall
Core polysaccharide
O polysaccharide
Lipopolysaccharide
Lipid A
Cell wall
Lipid A
Parts of the LPS
Porin protein
Lipoprotein
Outer membrane
Phospholipid
Peptidoglycan
Plasma
membrane
Periplasm
Protein
Gram-negative cell wall
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Gram-Positive Cell Walls
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Figure 4.13b Bacterial cell walls.
 Teichoic acids
 Lipoteichoic acid links to plasma membrane
 Wall teichoic acid links to peptidoglycan
Peptidoglycan
Wall teichoic acid
 May regulate movement of cations
 Polysaccharides provide antigenic variation
Lipoteichoic
acid
Cell wall
Plasma
Pl
membrane
Protein
O polysaccharide
Core polysaccharide
Lipid A
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Gram-Negative Outer Membrane
Figure 4.13c Bacterial cell walls.
 Lipopolysaccharides, lipoproteins, phospholipids
 Forms the periplasm between the outer membrane
and the plasma membrane
O polysaccharide
Core polysaccharide
Core polysaccharide
O polysaccharide
Lipopolysaccharide
Lipid A
Parts of the LPS
Lipid A
Cell wall
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Porin protein
Lipoprotein
Outer membrane
Phospholipid
Peptidoglycan
Plasma
membrane
Periplasm
Protein
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Gram-Negative Outer Membrane
The Gram Stain Mechanism
 Protection from phagocytes, complement, and
antibiotics
 O polysaccharide antigen, e.g., E. coli O157:H7
 Lipid A is an endotoxin
 Porins (proteins) form channels through membrane
 Crystal violet-iodine crystals form in cell
 Gram-positive
 Alcohol dehydrates peptidoglycan
 CV-I crystals do not leave
 Gram-negative
 Alcohol dissolves outer membrane and leaves holes in
peptidoglycan
 CV-I washes out
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Table 4.1 Some Comparative Characteristics of Gram-Positive and Gram-Negative Bacteria
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Gram-Positive
Cell Wall
Gram-Negative
Cell Wall
 2-ring basal body
 Disrupted by lysozyme
 Penicillin sensitive
 4-ring basal body
 Endotoxin
 Tetracycline sensitive
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Figure 4.13b-c Bacterial cell walls.
Atypical Cell Walls
 Acid-fast cell walls




Gram-positive cell wall
Like gram-positive cell walls
Waxy lipid (mycolic acid) bound to peptidoglycan
Mycobacterium
Nocardia
Gram-negative cell wall
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Figure 24.8 Mycobacterium tuberculosis.
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Atypical Cell Walls
 Mycoplasmas
 Lack cell walls
 Sterols in plasma membrane
 Archaea
 Wall-less
Wall less, or
 Walls of pseudomurein (lack NAM and D-amino acids)
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Damage to the Cell Wall




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Figure 4.14a Plasma membrane.
Lysozyme digests disaccharide in peptidoglycan
Penicillin inhibits peptide bridges in peptidoglycan
Protoplast is a wall-less cell
Spheroplast is a wall-less gram-positive cell
Lipid
bilayer of plasma
membrane
Peptidoglycan
 P
Protoplasts
t l t and
d spheroplasts
h
l t are susceptible
tibl tto osmotic
ti
lysis
O t membrane
Outer
b
Plasma membrane
of cell
 L forms are wall-less cells that swell into irregular
shapes
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The Plasma Membrane





Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane
P t i
Proteins
Figure 4.14b Plasma membrane.
Outside
Lipid
bilayer
Pore
Peripheral protein
Inside
Polar head
Nonpolar fatty
acid tails
Integral
proteins
Peripheral protein
Polar head
Lipid bilayer of plasma membrane
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Fluid Mosaic Model
The Plasma Membrane
 Membrane is as viscous as olive oil
 Proteins move to function
 Phospholipids rotate and move laterally
 Selective permeability allows passage of some
molecules
 Enzymes for ATP production
 Photosynthetic pigments on foldings called
chromatophores or thylakoids
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Figure 4.15 Chromatophores.
The Plasma Membrane
 Damage to the membrane by alcohols, quaternary
ammonium (detergents), and polymyxin antibiotics
causes leakage of cell contents
Chromatophores
ANIMATION Membrane Structure
ANIMATION Membrane Permeability
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Movement of Materials across
Membranes
Figure 4.17a Passive processes.
Outside
 Simple diffusion: movement of a solute from an
area of high concentration to an area of low
concentration
Plasma
membrane
Inside
Simple diffusion through
the lipid bilayer
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Movement of Materials across
Membranes
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Figure 4.17b-c Passive processes.
Nonspecific
transporter
 Facilitated diffusion: solute combines with a
transporter protein in the membrane
Transported
substance
Specific
transporter
Glucose
Facilitated
diffusion
through a
nonspecific
transporter
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Movement of Materials across
Membranes
Facilitated diffusion through
a specific transporter
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Figure 4.18a The principle of osmosis.
Glass tube
 Osmosis: the movement of water across a
selectively permeable membrane from an area of
high water to an area of lower water concentration
 Osmotic pressure: the pressure needed to stop the
movement of water across the membrane
Rubber
stopper
Rubber
band
Sucrose
molecule
Cellophane
sack
Water
molecule
At beginning of osmotic
pressure experiment
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Movement of Materials across
Membranes
Figure 4.17d Passive processes.
Aquaporin
 Through lipid layer
 Aquaporins (water channels)
Osmosis through the lipid bilayer
(left) and an aquaporin (right)
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Figure 4.18a-b The principle of osmosis.
Figure 4.18c-e The principle of osmosis.
Glass tube
Cytoplasm Solute
Plasma
membrane
Rubber
stopper
Rubber
band
Sucrose
molecule
Water
Isotonic solution.
No net movement
of water occurs.
Cellophane
sack
Water
molecule
At beginning of osmotic
pressure experiment
At equilibrium
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Movement of Materials across
Membranes
Hypotonic solution. Water moves
into the cell. If the cell wall is strong,
it contains the swelling. If the cell
wall is weak or damaged, the cell
bursts (osmotic lysis).
Hypertonic solution.
Water moves out of the
cell, causing its cytoplasm
to shrink (plasmolysis).
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Cytoplasm
 The substance inside the plasma membrane
 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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Figure 4.6 The Structure of a Prokaryotic Cell.
The Nucleoid
Pilus
 Bacterial chromosome
Cell wall
The drawing below and the
micrograph at right show a bacterium Capsule
sectioned lengthwise to reveal the
Although the nucleoid appears
internal composition. Not all bacteria
split in the photomicrograph,
have all the structures shown; only
the thinness of the “slice” does
structures labeled in red are found in
not convey theobject’s depth.
all bacteria.
Cytoplasm
70S Ribosomes
Plasma membrane
Nucleoid containing DNA
Inclusions
Plasmid
Fimbriae
Capsule
Cell wall
Plasma
membrane
Flagella
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.
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The Prokaryotic Ribosome
Figure 4.19 The prokaryotic ribosome.
 Protein synthesis
 70S
 50S + 30S subunits
50S
30S
Small subunit
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Large subunit
30S
Complete 70S
ribosome
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Figure 4.20 Magnetosomes.
Inclusions
Magnetosomes
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50S





Metachromatic granules (volutin)—phosphate reserves
Polysaccharide granules—energy reserves
Lipid inclusions—energy reserves
Sulfur granules—energy reserves
Carboxysomes—Ribulose 1,5-diphosphate carboxylase
for CO2 fixation
 Gas vacuoles—protein-covered cylinders
 Magnetosomes—iron oxide (destroys H2O2)
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Figure 4.21b Formation of endospores by sporulation.
Endospores





Endospore
Resting cells
Resistant to desiccation, heat, chemicals
Bacillus, Clostridium
Sporulation: endospore formation
G
Germination:
i ti
return
t
to
t vegetative
t ti state
t t
An endospore of Bacillus subtilis
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Figure 4.21a Formation of endospores by sporulation.
Cell wall
Figure 4.22a Eukaryotic cells showing typical structures.
Spore septum begins to isolate
newly replicated DNA and a
small portion of cytoplasm.
Cytoplasm
Plasma membrane starts to
surround DNA, cytoplasm, and
membrane isolated in step 1.
PLANT CELL
ANIMAL CELL
Peroxisome
Flagellum
Mitochondrion
Plasma
membrane
Microfilament
Bacterial
chromosome
(DNA)
Sporulation, the process of endospore
formation
Golgi complex
Microtubule
Spore septum surrounds isolated portion,
forming forespore.
Vacuole
Chloroplast
Ribosome
Two
membranes
Cytoplasm
Smooth endoplasmic
reticulum
Peptidoglycan
layer forms between membranes.
Cell wall
Spore coat forms.
Nucleolus
Plasma membrane
Highly schematic diagram of a composite eukaryotic cell,
half plant and half animal
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Nucleolus
Golgi complex
Basal body
Cytoplasm
Microfilament
Lysosome
Centrosome:
Centriole
Pericentriolar material
Ribosome
Microtubule
Nucleus
Endospore is freed
from cell.
Nucleus
Peroxisome
Rough endoplasmic
reticulum
Mitochondrion
Smooth endoplasmic
reticulum
Plasma membrane
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Figure 4.23a-b Eukaryotic flagella and cilia.
Flagella and Cilia
 Microtubules
 Tubulin
 9 pairs + 2 array
Flagellum
Cilia
A micrograph of
Euglena, a chlorophyllcontaining alga, with its
flagellum.
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A micrograph of
Tetrahymena, a common
freshwater protozoan,
with cilia.
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Figure 4.23c Eukaryotic flagella and cilia.
Central
microtubules
Doublet
microtubules
The Cell Wall and Glycocalyx
 Cell wall
Plasma
membrane
 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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The internal structure of a flagellum (or cilium), showing
the 9 + 2 arrangement of microtubules.
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The Plasma Membrane
The Plasma Membrane






 Selective permeability allows passage of some
molecules
 Simple diffusion
 Facilitative diffusion
 Osmosis
 Active transport
 Endocytosis
Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane proteins
St l
Sterols
Glycocalyx carbohydrates
 Phagocytosis: pseudopods extend and engulf particles
 Pinocytosis: membrane folds inward, bringing in fluid and
dissolved substances
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Table 4.2 Principal Differences between Prokaryotic and Eukaryotic Cells
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Cytoplasm
 Cytoplasm membrane: substance inside plasma
and outside nucleus
 Cytosol: fluid portion of cytoplasm
 Cytoskeleton: microfilaments, intermediate
filaments microtubules
filaments,
 Cytoplasmic streaming: movement of cytoplasm
throughout cells
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Ribosomes
Organelles
 Protein synthesis
 80S





 Membrane-bound: attached to ER
 Free: in cytoplasm
 70S
 In chloroplasts and mitochondria
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Figure 4.24c The eukaryotic nucleus.
Organelles




Nucleus: contains chromosomes
ER: transport network
Golgi complex: membrane formation and secretion
Lysosome: digestive enzymes
V
Vacuole:
l brings
bi
ffood
d iinto
t cells
ll and
d provides
id supportt
Mitochondrion: cellular respiration
Chloroplast: photosynthesis
Peroxisome: oxidation of fatty acids; destroys H2O2
Centrosome: consists of protein fibers and
centrioles
Nuclear
pore(s)
Nuclear
envelope
Nucleolus
Chromatin
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Figure 4.24a-b The eukaryotic nucleus.
Figure 4.25 Rough endoplasmic reticulum and ribosomes.
Nuclear envelope
Ribosomes
Nuclear
pore(s)
Cisternae
Nuclear
envelope
Ribosomes
Nucleolus
Chromatin
Smooth ER Ribosomes
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Rough ER
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Figure 4.25a Rough endoplasmic reticulum and ribosomes.
Figure 4.25b Rough endoplasmic reticulum and ribosomes.
Smooth ER
Ribosomes
Ribosomes
Rough ER
Nuclear envelope
Cisternae
Smooth ER
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Rough ER
Figure 4.26 Golgi complex.
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Figure 4.22b Eukaryotic cells showing typical structures.
Animal cell, an
antibody-secreting
plasma cell
Peroxisome
Nucleus
Vacuole
Secretory
vesicles
Chloroplast
Golgi complex
Mitochondrion
Transfer
vesicles
Cisternae
Plasma membrane
Nucleus
Cytoplasm
Nucleolus
Cell wall
Transport
vesicle from
rough ER
Algal cell
(Tribonema vulgare)
Mitochondrion
Rough endoplasmic
reticulum
Lysosome
Transmission electron micrographs of plant and animal cells.
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Figure 4.27 Mitochondria.
Figure 4.28 Chloroplasts.
Granum
Matrix
Cristae Inner
membrane
Outer
membrane
Thylakoids
Chloroplast
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Figure 4.28a Chloroplasts.
Figure 4.28b Chloroplasts.
Thylakoids
Chloroplast
Granum
Thylakoids
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Figure 4.22b Eukaryotic cells showing typical structures.
Peroxisome
Nucleus
Vacuole
Figure 10.2 A model of the origin of eukaryotes.
Animal cell, an
antibody-secreting
plasma cell
Chloroplast
Golgi complex
Mitochondrion
Plasma membrane
Nucleus
Cytoplasm
Nucleolus
Cell wall
Algal cell
(Tribonema vulgare)
Mitochondrion
Rough endoplasmic
reticulum
Lysosome
Transmission electron micrographs of plant and animal cells.
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Endosymbiotic Theory
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Applications of Microbiology 4.1 Mixotricha, a protozoan that lives in the termite gut.
 What are the fine extensions on the protozoan
shown on the following slide?
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Applications of Microbiology 4.2 Arrangements of bacteria on the surfaces of two protozoans.
Protozoan flagella
Spirochetes
Bracket
Filament composed of
overlapping flagella
Rod-shaped
bacteria in
grooves
Protozoan
surface
Protozoan
surface
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