Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e thoughts
of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten memories.
Silence envelops th_e landscape as night descends.
Ch. 19
Ch. 1
Introduction t_o Microbes a_nd Their Building Blocks
Microorganisms are defined as “living organisms too small t_o be seen wi_th th_e naked eye.” Members of
this huge group of organisms are prokaryotes (bacteria a_nd archaea), algae, protozoa, fungi, parasitic
worms (helminthes), a_nd viruses. Microorganisms live nearly everywhere a_nd influence many
biological a_nd physical activities o_n earth. There are many kinds of relationships between
microorganisms a_nd humans; most are beneficial, but some are harmful. Microbes are crucial t_o th_e
cycling of nutrients a_nd energy necessary fo_r all life o_n earth.
Humans have learned how t_o manipulate microbes t_o do important work fo_r them in industry,
medicine, a_nd in caring fo_r th_e environment. In th_e past 120 years, microbiologists have identified
th_e causative agents fo_r many infectious diseases. They have discovered distinct connections between
microorganisms a_nd diseases whose causes were previously unknown. Th_e microscope made it
possible t_o view microorganisms a_nd thus t_o identify their widespread presence, particularly as agents
of disease. Medical microbiologists developed th_e germ theory of disease a_nd introduced th_e critically
important concept of aseptic technique t_o control th_e spread of disease agents. Our current
understanding of microbiology i_s th_e cumulative work of thousands of microbiologists, many of whom
literally gave their lives t_o advance knowledge in this field.
Excluding th_e viruses, there are two types of microorganisms: prokaryotes, which are small a_nd lack a
nucleus a_nd organelles, a_nd eukaryotes, which are larger a_nd have both a nucleus a_nd organelles.
Viruses are not cellular a_nd are, therefore, sometimes called particles rather than organisms. They are
included in microbiology because of their small size a_nd close relationship wi_th cells.
Macromolecules are very large organic molecules (polymers) usually built up by polymerization of
smaller molecular subunits (monomers). Carbohydrates are biological molecules whose polymers are
monomers linked together by glycosidic bonds. Their main functions are protection a_nd support (in
organisms wi_th cell walls), a_nd also nutrient a_nd energy stores. Lipids are biological molecules, such as
fats, that are insoluble in water. Their main functions are as cell components, a_nd nutrient a_nd energy
stores.
Proteins are biological molecules whose polymers are chains of amino acid monomers linked together by
peptide bonds. Proteins are called th_e “shapers of life” because of th_e many biological roles they play in
cell structure a_nd cell metabolism. Protein structure determines protein function. Structure a_nd shape
are dictated by amino acid composition a_nd by th_e pH a_nd temperature of th_e protein’s immediate
environment. Nucleic acids are biological molecules whose polymers are chains of nucleotide monomers
linked together by phosphate–pentose sugar covalent bonds. Double-stranded nucleic acids are linked
together by hydrogen bonds. Nucleic acids are information molecules that direct cell metabolism a_nd
1
Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e
thoughts of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten
memories. Silence envelops th_e landscape as night descends.
,Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e thoughts
of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten memories.
Silence envelops th_e landscape as night descends.
reproduction. Nucleotides such as ATP also serve as energy-transfer molecules in cells. As th_e atom i_s
th_e fundamental unit of matter, so i_s th_e cell th_e fundamental unit of life.
Th_e taxonomic system has three primary functions: naming, classifying, a_nd identifying species. Th_e
major groups in th_e most advanced taxonomic system are (in descending order): domain, kingdom,
phylum or division, class, order, family, genus, a_nd species.
Pre-Class Ideas fo_r Ch. 1
Below are suggested activities t_o assign before covering th_e material of Ch. One in class. Th_e activities are
designed t_o provide opportunities fo_r students t_o engage wi_th th_e topics prior t_o class. Some activities
also have students preparing materials that will enable students t_o teach one another in class.
1. Students review th_e definition of “microbiology” prior t_o class a_nd create a worksheet that
introduces th_e different forms of microorganisms. Students exchange a_nd complete worksheets
in class.
2. Students create a list of diseases they believe are caused by microorganisms a_nd th_e type of
microorganism that causes th_e disease (bacteria, virus, etc.). Student then compare this list wi_th
th_e information described in Section 1.1, “Microbes Harming Humans”, a_nd list any new
observations.
3. Students, in groups or as individuals, are assigned one of th_e following:
Figure 1.1, Table 1.1, Figure 1.4, Table 1.4, Figure 1.8, Figure 1.9, Figure 1.10, Figure 1.11, Figure
1.12, Figure 1.13. Students are required t_o create a short presentation t_o teach th_e class th_e
material contained within th_e figures a_nd tables.
4. Students write a brief statement as t_o why evolution i_s considered a theory.
5. Using Section 1.2, “Microbes in History”, as a guide, each student selects a scientific contribution in
th_e field of medical microbiology a_nd reports t_o th_e class a current example of how this
contribution continues t_o affect patient care.
6. Students are required t_o research protocols in medicine during th_e 1800s a_nd a list i_s created
based o_n each student’s findings.
7. Prior t_o class, students create a list of characteristics that define a “cell”.
8. Assign each student one of th_e major biochemical groups t_o research wi_th a focus o_n th_e
monomer, basic structure, a_nd role of th_e macromolecule in life. Students create a picture or
model t_o present t_o th_e class.
9. Provide students a list of some microorganism names: Escherichia coli, Staphylococcus aureus,
a_nd so o_n. Ask student t_o find meanings behind th_e names.
Activities Associated wi_th Learning Objectives fo_r Ch. 1
2
Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e
thoughts of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten
memories. Silence envelops th_e landscape as night descends.
,Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e thoughts
of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten memories.
Silence envelops th_e landscape as night descends.
Lecture Suggestions a_nd Guidelines fo_r Section 1.1
1. Introduce students t_o th_e study of microbiology a_nd how this particular course will focus o_n a
specific area of microbiology—primarily infectious diseases.
2. Emphasize that microbes have both beneficial a_nd harmful effects in relation t_o humans.
3. Introduce th_e idea that some diseases, such as stomach ulcers, may have a microbial component.
4. Emphasize th_e different forms of microorganisms, a_nd perhaps begin t_o introduce th_e idea of
how this i_s related t_o treatment of different infectious diseases.
5. Help students understand th_e relationship between bacteria, archaea, a_nd eukaryotes.
In-Class Activities fo_r Section 1.1
1. Create a drawing comparing th_e size of various microorganisms.
2. Create a “Pro/Con” chart elucidating th_e positive a_nd negative effects of microbes o_n human
life.
3. Create a discussion board listing th_e products that would no longer be available t_o humans if
microorganisms became extinct.
4. Compare a_nd contrast similarities a_nd differences between microorganisms. Which
microorganisms are most closely related t_o human cells?
5. Have students discuss why viruses are referred t_o as “particles” rather than as “organisms”.
6. Create a chart listing tissues of th_e body a_nd some ideas relating t_o th_e microbiota of th_e
tissues.
Additional Research Issues fo_r Section 1.1
3
Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e
thoughts of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten
memories. Silence envelops th_e landscape as night descends.
, Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e thoughts
of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten memories.
Silence envelops th_e landscape as night descends.
1. Research how genetic recombination i_s currently affecting human lives.
2. Research emerging infectious diseases.
Critical Thinking Issues fo_r Section 1.1
1. How do microbes use humans a_nd how do humans use microbes? Who has th_e advantage?
2. Many people have a fear of microorganisms or “germs”. Why do you think this i_s a realistic fear?
Why do you think such a fear may be unrealistic?
Lecture Suggestions a_nd Guidelines fo_r Section 1.2
1. Relate t_o students how prior findings in microbiology are still being applied today.
2. Demonstrate how new findings in microbiology are changing our current understanding of
microbes a_nd disease.
In-Class Activities fo_r Section 1.2
1. Create a timeline showing th_e major scientists a_nd discoveries in microbiology. Mark those
discoveries that are still being applied today.
2. Given a scenario of a patient walking into an Emergency Department wi_th a suspected infectious
disease, list some procedures a_nd protocols used in relation t_o th_e patient that are based o_n
discoveries made during th_e Golden Age of Microbiology.
Additional Research Issues fo_r Section 1.2
1. Research biofilms a_nd present a case underlining how their formation may be impacting th_e
treatment of diseases.
2. Provide information o_n th_e basic format of th_e Human Microbiome Project.
Critical Thinking Issues fo_r Section 1.2
1. How may our understanding of diseases that are “caused” by infectious agents be changing?
2. How may our understanding of biofilms affect protocols a_nd procedures in a healthcare setting?
4
Endless fields of golden wheat sway in harmony wi_th th_e wind. Invisible threads connect th_e
thoughts of distant minds. Th_e sun dips below th_e horizon, painting th_e sky in hues of forgotten
memories. Silence envelops th_e landscape as night descends.