CHAPTER 4
CHARACTERISTICS OF PROKARYOTIC AND EUKARYOTIC CELLS
CHAPTER OVERVIEW
This chapter provides an in-depth look at the structure and
function of prokaryotic and eukaryotic cells.
A detailed study of prokaryotic structure is extremely
valuable
because
it
provides
important
information
on
how
antibiotics work, how microbes undergo metabolism, how antibiotic
resistant develops, and how differential stains such as the Gram
stain work. Even though prokaryotes are considerably simpler than
eukaryotic cells, they still possess many complex structures, such
as peptidoglycan layers and endospores that are not found in any
other living organism. However, when prokaryotic and eukaryotic
cells are compared, similarities can also be found. For example,
the cell membrane in prokaryotes is basically identical to the cell
membrane in eukaryotic cells.
A study of similarities and
differences can help the student understand important biochemical
and evolutionary changes.
The last part of the chapter provides a brief presentation of
the
important
mechanisms
that
move
substances
across
cell
membranes. An understanding of these mechanisms is essential to an
understanding of how the cell functions. Both passive and active
processes are presented, with the emphasis placed on those
mechanisms that are most important to microbiologists. Since this
chapter may be considered the foundation for later chapters,
sufficient time in lecture should be devoted to ensure thorough
coverage.
CHAPTER OBJECTIVES






Contrast the characteristics of eukaryotic and prokaryotic cell
types.
Describe the sizes, shapes, and arrangements of prokaryotic
cells, especially as they relate to bacterial cells.
Describe the basic structure and function of the cell membrane
and cell wall of bacterial cells.
List and describe the structure and function of internal cell
components of bacteria, including endospores.
Describe the structure and function of the external cell
components of bacteria.
Describe the general structure of eukaryotic cells.
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
List and describe the structure and function of the internal
components of eukaryotic cells.
4-2





Describe the structure and function of the external components of
eukaryotic cells.
Explain the endosymbiotic theory and give examples of organelles
that may have evolved by endosymbiosis.
Describe the following passive processes, and explain their
importance in cell function:
simple diffusion, facilitated
diffusion, and osmosis
Describe the process of active transport, explaining how it
differs from passive processes and why it is important in cell
function.
Describe the processes of exocytosis and endocytosis, and explain
their importance in eukaryotic cell function.
CHAPTER OUTLINE
I.
Basic Cell Types
A.
Prokaryotic cells
B.
Eukaryotic cells
II.
Prokaryotic Cells
A.
Size, shape, and arrangement
1.
Size
2.
Shapes
3.
Arrangements
B.
Overview of structure
C.
Cell wall
1.
Basic functions
2.
Components of cell walls
a.
Peptidoglycan
b.
Teichoic acids
c.
Outer membrane
d.
Lipopolysaccharide
e.
Periplasmic space
3.
Distinguishing bacteria by cell walls
a.
Gram-positive bacteria
b.
Gram-negative bacteria
c.
Acid-fast bacteria
d.
Controlling bacteria by damaging cell walls
4.
Wall-deficient organisms
D.
Cell membrane
1.
Basic functions
2.
Fluid-mosaic model
a.
Hydrophilic
b.
Hydrophobic
E.
Internal structure
4-3
1.
2.
Cytoplasm
Ribosomes
4-4
3.
4.
5.
F.
Nuclear region
Internal membrane systems
Inclusions
a.
Granules
b.
Vesicles
6.
Endospores
a. Sporulation
b. Germination
External structure
1.
Flagella
a.
Types of flagella
b.
Composition
c.
Chemotaxis
d.
Phototaxis
2.
Axial filaments
3.
Pili
a.
Conjugation pili
b.
Attachment pili
4.
Glycocalyx
a.
Capsule
b.
Slime layer
III. Eukaryotic Cells
A.
Overview of structure
B.
Plasma membrane
C.
Internal structure
1.
Cytoplasm
2.
Cell nucleus
a.
Basic features
b.
Chromosomes
c.
Mitosis
d. Meiosis
3.
Mitochondria
4.
Chloroplasts
5.
Ribosomes
6.
Endoplasmic reticulum
7.
Golgi apparatus
8.
Lysosomes
9.
Peroxisomes
10. Vacuoles
11. Cytoskeleton
D.
External structure
1.
Flagella
2.
Cilia
3.
Pseudopodia
4.
Cell walls
4-5
E.
IV.
Evolution by endosymbiosis
1. Endosymbiotic theory
2. Supporting evidence
Movement of Substances Across Membranes
A.
Basic characteristics
B.
Simple diffusion
C.
Facilitated diffusion
D.
Osmosis
1.
Osmotic pressure
2.
Tonicity
E.
Active transport
F.
Endocytosis and exocytosis
1.
Endocytosis
2.
Exocytosis
 Teaching Tips







Obtain models of eukaryotic and prokaryotic cells to provide a
visual comparison of the two.
Students often have difficulty with size relationships of
microorganisms. Use visual aids such as slides, transparencies,
or handouts that illustrate the sizes of microorganisms.
Bacterial cell wall construction is a very important topic, but
difficult for students to understand. Use a variety of graphics
to illustrate peptidoglycan composition.
Make a comparison of similarities and differences between grampositive and gram-negative cells.
Video:
Cell Motility and Microtubules (30 min, C, VHS)
Illustrates ciliary and flagellar movements in a variety of
organisms. (EX1138, FFH)
Remind students of the similarities between eukaryotic and
prokaryotic cells as well as their differences.
Discuss the endosymbiont concept of how bacteria may have evolved
into mitochondria and chloroplasts for eukaryotic cells.
 Web Destinations

http://www.liunet.edu/cwis/bklyn/acadres/facdev/FacultyProjects/W
ebClass/micro-web/html-files/chapterA-1.html
Long Island University site covers the cell biology of
prokaryotic and eukaryotic cells.
4-6

http://web.mit.edu/esgbio/www/cb/prok_euk.html
M.I.T. site covers the cell biology of prokaryotic and eukaryotic
cells.
4-7


http://medic.med.uth.tmc.edu/path/00001443.htm
This web site from the University of Texas Medical School
provides information and images about gram-negative bacteria.
http://www.bact.wisc.edu/Microtextbook/TOC.html
On-line microbiology textbook
 Discussion Topics


How could the process of endocytosis be used selectively to cause
microbes to ingest antibiotics or other poisonous substances?
Discuss the major unique bacterial components, peptodglycan and
70S ribosomes.
Explain how antibiotics target these unique
characteristics to control bacterial infections.
 Track It Down



The fluid-mosaic model suggests that cell membranes and plasma
membranes are very dynamic and active structures. Propose some
theories about the value of mobile proteins in these membranes.
Endospores are highly resistant and impervious to virtually all
conditions and substances.
How then can they detect when
conditions are favorable for germination?
Eukaryotic cells have a cell membrane and internal structures
similar to bacteria.
Why then do antibiotics affect bacteria
preferentially?
 Additional Resources



Unseen Life on Earth: An Introduction to Microbiology Part 2 The Unity of Living Systems (30 min., C, 1999, VHS). A 12-part
series produced in part by the American Society for Microbiology
that explains basic microbial principles and how microbes affect
everything from medicine to environmental issues to global
politics. (CA00125-ULSVE, CPB)
Viruses and Bacteria (CD-ROM, 1999).
This CD-ROM features
digital microscope slide images of viruses and bacteria that can
be magnified and manipulated. (BAA 1308, IM)
Cells:
An Introduction (20 min., C, VHS).
This program
illustrates a virtual journey through the cell describing the
types, structures, components, and functions of both eukaryotes
and prokaryotes. (FHC 8229, FFH)
4-8

Cell Functions: A closer Look (20 min., C, VHS). This program
examines three main activities of the cell: energy storage and
release, protein synthesis, and cell reproduction.
(FHC 8230,
FFH)
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

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

A Journey Through the Cell (50 min., C, 1997, VHS – 2 Volumes).
This set combines live-action footage, computer graphics, and
animation in an exploration of cell structure and function. (BZ
939, IM)
CELLebration (36 min., C, 1995, VHS – 4 parts).
This video,
sponsored by ASCB, is a collection of footage filmed by
researchers using DIC, fluorescence, and time-lapse photography.
(BZ 860, IM)
Introduction to Cells: The Structure of the Cell (1989, CD-ROM).
This older CD presents basic structures of the cell and their
functions along with a description of the differences between
plant and animal cells. (BZ 1442, IM)
The Plasma Membrane and Cellular Transport (1997, CD-ROM). This
program uses models, graphics, and narratives to highlight the
importance of the membrane that surrounds the cell. (AAZ 31355,
EDU)
What are Bacteria? (17 min., C, 1999, VHS).
This video
introduces the two kingdoms of bacteria, Archaebacteria and
Eubacteria, and explains their characteristics and features.
(AAZ 21525, EDU)
Voyage Inside the Cell (15 min., C, VHS). This program uses 3-D
computer animation to follow a hormone on its journey through the
cell. (FKJ 10830, FFH)
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