Microbiology An Introduction 10e
Tortora, Funke and Case
Outline
Note: The following abbreviations are used to indicate objectives and questions
you need to know for the exams
LO = Learning Objectives found at the beginning of text sections
CYU = Check Your Understanding questions found at the end of text sections
Q = Questions found under figures
Study Questions at the end of each chapter: (R = Review, MC = Multiple Choice,
CT = Critical Thinking, CA = Clinical Applications)
Chap. 4 Functional Anatomy of Prokaryotic and Eukaryotic Cells
LO/CYU: 4-1
I. Comparing Prokaryotic and Eukaryotic Cells: An Overview
p. 76-77, Also see Table 4.2 p. 101
Fig. 4.6 p. 80 Foundation Figure The Structure of a Prokaryotic Cell
Slide 1
Fig. 4.22 p. 99 The Eukaryotic Cell
Slide 2
Table 4.2 p. 101 Photograph
Slide 3
FYI: Slide 3
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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The Prokaryotic Cell
Intro:
 As you go through the chapter, note ways that Archaea differ from
Bacteria
 How are bacteria differentiated from one another?
 As you go through the chapter, note ways that Prokaryotes differ from
Eukaryotes
II. The Size, Shape, and Arrangement of Bacterial Cells
LO/CYU: 4-2
A. Size: ~0.2m in diameter and 2-8m in length
B. Shapes and Arrangements: Be able to recognize the basic shapes and
arrangements
1. Be able to recognize the basic shapes (plus be aware that there are
others-star, square, etc.)
Fig. 4.1, 4.2, & 4.4 p. 78, 79, Fig. 4.5 p. 79
a. Coccus
b. Bacillus
c. Spiral (vibrio, spirilla, spirochetes)
-monomorphic v. pleomorphic
2. Be able to recognize the arrangements: single, diplo, strepto,
tetrads, sarcinae, staphylococcus, coccobacilli
Fig. 4.1 p. 78, Fig. 4.2 p. 79
III. Structures External to the Cell Wall
p. 79-84
See Fig. 4.6 p. 80 Foundation Figure The Structure of a Prokaryotic Cell (Slide 1)
A. Glycocalyx
Slide 4-8
2
LO/CYU: 4-3
What is the importance of the glycocalyx?
3
B. Flagella Fig. 4.7 p. 81
LO/CYU: 4-4
Slide 9
1. Taxis- movement toward/away from a stimulus
2. Several proteins, including flagellin
3. H antigen (a protein in flagella)- distinguishes between variations
within a species (serovars)
E. coli 0157:H7 (food-borne epidemics)
C. Axial Filaments: Spirochetes only (Ex.: Trepnema)
Fig. 14.11 a p. 84
Slide 10
D. Fimbriae and Pili (shorter, straighter, thinner than flagella) p.83
1. Contain protein pilin
2. Fimbriae Fig. 14.10 b p. 84
Slide 11
a. Attachment
b. A few to several hundred per cell.
c. Ex.: Neisseria gonorrhoeae (see Fig. 11.6 p. 306)
and E. coli 0157:H7 (see text p. 717-718)
2. Pili
Slide 12
a. Usually longer than fimbriae and only 1 or 2 per cell.
b. Motility: Twitching and Gliding
c. Conjugation pili
(Transfer of DNA from one bacterial cell to another)
See Fig. 8.26 p. 237 Bacterial conjugation.
4
IV. The Cell Wall
LO/CYU: 4-5
Major function of the cell wall?
A. Composition and Characteristics
Figure 4.6 p. 80 The Structure of the Prokaryotic Cell Wall
Fig. 4.13 a Bacterial Cell Walls p. 86 Slides 13-18
Peptidoglycan (murein)
Only in bacterial cell
walls.
Slide 1
Slide 13
-Disaccharide (NAG-NAM)
-The rows of NAG-NAMs are connected by side chains made of 4
amino acids
-Short peptide cross-bridges may also be present that link the side
chains
1. Gram-Positive Cell Walls
Slide 14
a. Many layers of peptidoglycan
b. Teichoic acids (alcohol and phosphate) present
c. Other molecules may be present (Different Strep “groups”
have specific polysaccharides)
Example G+: Staphylococcus aureus (MRSA, impetigo, a form of toxic shock syndrome),
Streptococcus pyogenes (strep throat, flesh-eating bacteria, a form of toxic shock syndrome,
scarlet fever) Slide 15
5
2. Gram-Negative Cell Walls
Fig. 4.13 c p. 86 Gram-negative cell wall details
Slide 16
a. Periplasm
1) Contains one or only a few peptidoglycan layers
2) Lipoproteins connect the peptidoglycan to the outer
membrane (see below)
3) Other molecules: Ex: degradative enzymes and
transport proteins
b. Outer Membrane (OM)
OM is semi-permeable: only allows
some things in and out of the cell,
some things are restricted.
IMPORTANT!!! Certain drugs and
chemicals won’t penetrate the OM
and can’t be used- ex: penicillin is
less effective against G- cells.
1) Phospholipid bilayer
2) Porin proteins with a channel for transporting nutrients
into the cell
3) Lipopolysaccharide (LPS, endotoxin)
Slide
a) Released from the OM when the cell lyses.
BAD!! Common cause of most
severe form of sepsis, called septic
shock: fever, blood vessel dilation,
blood clotting (organ damage,
death) Slide 17
Examples G-: E. coli O157:H7, Yersinia
pestis (plague)
b) 3 parts to an LPS molecule:
(1) Lipid A anchors the LPS in the top
phospholipid layer of OM
(2) Core polysaccharide stabilizes the LPS
(3) O polysaccharide extends out from the
core polysaccharide
Different species have distinctive O
polysaccharides which can be used for
identification.
E. coli 0157: H7
6
B. Cell Walls and Gram Staining
Slide 18
C. Atypical Cell Walls
1. Archaea: May have no cell walls, and if they do, they never
contain peptidoglycan. If they do have cell walls, may contain
pseudomurein , which has N-acetyltalosaminuronic instead of
NAM
2. Bacteria with no cell walls: Mycoplasmas, Spiroplasma,
Ureaplasma
LO/CYU: 4-6
Mycoplasmas are the smallest free-living cellular organisms known
(0.1-2.5 micrometers). Since no cell wall, often are pleomorphic.
Also contain sterols in their plasma membrane (protection from lysis).
Mycoplasm pneumoniae causes a mild form of pneumonia.
(What type of other microorganism does this bacterial name refer to?)
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3. Acid-Fast Cell Walls: Mycobacterium
See Fig. 24.8 Mycobacterium tuberculosis p. 682
a. Mycolic acids take the place of the OM; connect to a thin
peptidoglycan layer with polysaccharides
b. Mycolic acids are lipids, waxy and water resistant.
c. Mycolic acids are why these cells are:
 Difficult to stain (can stain by heating with the red acidfast stain, carbolfuchsin, that bonds to waxy materials)
 Resistant to many drugs, disinfectants and antiseptics,
and stresses (such as low water content-don’t dry out
easily)
 Slow growing (nutrients enter slowly) and cause certain
diseases (mycolic acids stimulate the inflammatory
response -many white blood cell macrophages come to
destroy the bacteria and release cytokines and enzymes
that actually damage lung tissues).
 Important diseases: M. tuberculosis, M. leprae, Nocardia
D. Damage to Cell Wall p. 88, 89
1. Why don’t chemicals that damage bacterial cell walls or prevent
their synthesis cause damage to the cell walls of humans?
2. Penicillin
3. Lysozyme
Why do chemicals that affect the cell wall
of bacteria, especially the peptidoglycan,
most often work best with Gram-positive
bacteria?
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V. Structures Internal to the Cell Wall
A. Plasma Membrane (or inner membrane if you are Gram-)
1. Structure
LO/CYU: 4-8
Fig. 4.14 p. 90
Slide 19
Fluid Mosaic Model
a. Phospholipid bilayer
Hydrophobic and Hydrophilic components
b. Proteins
c. Carbohydrates attached to a lipid: glycolipids
Carbohydrates attached to protein: glycoprotein
Roles in protection, cell interactions, bonding sites for
pathogens (influenza viruses, cholera and botulism
toxins)
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Instructor’s Note: Archeal membranes are structurally different from
Bacteria/Eukaryotic membranes
Notice
branching
Archaea
Side
chains
Bacterial, Eukarya
No
branching
1. Glycerol component (found with the phosphate in the ‘head’) is a ‘mirror image’
(stereoisomer) of bacterial and eukaryal cell membrane glycerol.
2. Linkage (type of bond) between the glycerol and side chains (‘tails’) is different. This results
in different properties.
3. Side chains are not fatty acids in Archaea. Isoprenes are common.
2. Functions of the Plasma Membrane
a. Selective permeability
b. Nutrient break-down (enzymes)
c. ATP production (efficient energy)
d. Photosynthesis enzymes and pigments
Note: See Fig. 20.2 p. 556 for Major
modes of Action of Antimicrobial
Drugs
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3. Destruction of the Plasma Membrane
a. Certain disinfectants (example alcohols)
b. Certain antibiotics: polymyxins
B. Movement of Materials across Membranes
LO/CYU: 4-9
1. Passive Processes – No energy used
a. Simple and Facilitated Diffusion
Fig. 4.17 a, b, c p. 92
Slides 20, 21
b. Osmosis Fig. 4.17d p. 92 and Fig. 4.18 p. 93
Slides 22, 23
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2. Active Processes – Use energy
Use transporter proteins, enzymes, other processes
a. Active Transport: Requires a transporter protein
b. Group Translocation: Requires a transporter protein
Substance is chemically altered as it is being transported into
the cell. -Only occurs in Prokaryotes
c. Endocytosis & Exocytosis : Only occur in Eukaryoytes
B. Cytoplasm
C. Nucleoid
LO/CYU: 4-10
Bacterial chromosome vs. Plasmids
Fig. 4.6 p. 80
D. Ribosomes
E. Inclusions
LO/CYU: 4-11
F. Endospores- Sporulation/Germination
LO/CYU: 4-12
Fig. 4.21 p. 97
Slide 24
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The Eukaryotic Cell
Fig. 4.22 p. 99 Eukaryotic cells showing typical structures.
Slide 2
Principle Differences between Prokaryotic and Eukaryotic Cells Table 4.2 p. 101
CYU: 4-4-13-4-16
I. Flagella and Cilia
II. The Cell Wall and Glycocalyx
III. Plasma (Cytoplasmic) Membrane
LO/CYU: 4-16
IV. Cytoplasm
V. Ribosomes
LO/CYU: 4-17
VI. Organelles (Membrane-bound)
Slides 25-27
A. Nucleus Fig. 4.24 a, b p. 102
CYU: 4-18
B. Endoplasmic Reticulum: rough and smooth
C. Vesicles & Golgi Complex
D. Lysosomes
E. Mitochondria
F. Chloroplasts
G. Peroxisomes
H. Centrosome
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VII. Evolution of Eukaryotes
A. Endosymbiotic Theory
LO: 4-20
Fig. 10.2 p. 277 A model of the origin or eukaryotes
Slide 28
Table 10.2 p. 276 Prokaryotic Cells and Eukaryotic Organelles Compared
Slide 29
Further discussion concerning the differences between the 3 Domains and
Organelles:
Fig. 10.1 p. 275 The Three Domain System
Slide 30
Table 10.1 p. 276 Some Characteristics of Archaea, Bacteria, and Eukarya
Slide 31
Additional study Questions:
End of Chapter Study Question:
Review: 2, 4, 5, 6, 7c&e, 9
Multiple Choice: 1, 2, 3, 9
Critical Thinking: 3, 4
Clinical Applications: 1
Slide List (PPt)
Slide 1 Fig. 4.6 p. 80 Foundation Figure The Structure of a Prokaryotic Cell
Slide 2 Fig. 4.22 Eukaryotic cells showing typical structures p. 99
Slide 3 Picture from Table 4.2 Comparing Sizes of Prokaryotic and Eukaryotic Cells
Slide 4 Glycocalyx Fig. unknown source
Slides 5-8 Fig. 8.24 Griffith’s experiment demonstrating genetic transformation p. 235
Slide 9 Fig. 4.7 p. 81 Arrangements of bacterial flagella
Slide 10 Fig. 4.11 a p. 84
Spirochete Leptospira, showing axial filament
Slide 11 Fig. 4.11 b p. 84 Fimbriae. The fimbriae seem to bristle from this E. coli
cell, which is beginning to divide.
Slide 12 Fig. 8.26 p. 237 Bacterial conjugation (showing pili)
Slide 13 Fig. 4.13 a p. 86 Bacterial cell walls. Small arrows are where penicillin
interferes with linking of peptidoglycan rows by peptide cross bridges.
Slide 14 Fig. 4.13 b p. 86 Bacterial cell walls. A gram-positive cell wall.
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Slide 15 Fig. 21.4 Lesions of Impetigo p. 588 – caused by Staph aureus and
Fig. 21.8 Necrotizing fasciitis –caused by group A streptococci
Slide 16 Fig. 4.13 c p. 86 Gram-negative cell wall
details
Slide 17 Fig. 23.3 Lymphangitis, one sign of sepsis. As the infection spreads from
its original site along the lymph vessels, the inflamed walls of the vessels become
visible as red streaks. p. 640
Slide 18 Table 4.1 p. 88 Some Comparative Characteristics of Gram-Positive and
Gram-Negative Bacteria (pictures)
Slide 19 Fig. 4.14 Plasma membrane p. 90
Slide 20 Fig. 4.17 a) p. 92 Facilitated diffusion through the lipid bilayer
Slide 21 Fig. 4.17 b) & c) p. 92 Facilitated diffusion through b) a nonspecific
transporter and c) a specific transporter
Slide 22 Fig. 4.17 d) p. 92 Osmosis through the lipid bilayer and an aquaporin
Slide 23 Fig. 4.18 The principle of osmosis
Slide 24 Fig. 4.21 Formation of endospores by sporulation p. 97
Slide 25 Fig. 4.24 The eukaryotic nucleus p. 102
Slide 26 & 27 Organelles found only in Eukaryotic cells
Slide 28 Fig. 10.2 p. 277 A model of the origin or eukaryotes: Endosymbiotic
Theory
Slide 29 Table 10.2 p. 276 Prokaryotic Cells and Eukaryotic Organelles Compared
Slide 30 Foundation Fig. 10.1 The Three Domain System p. 275
Slide 31 Table 10.1 Some characteristics of Archaea, Bacteria, and Eukarya p. 276
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