Chapter 1 – The microbial world and you
Microbes in our lives
Overall theme of this course is to discuss microbes and how they are involved in the lives of
humans. Microbes make the biggest news when they are causing harm
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Microbiology – The study of ______________
Microbe – living things _______________to be seen with the _________________
o aka, Microorganisms, germs, bugs
o Includes bacteria, fungus, protists, algae, viruses
o Huge diversity in ___________________ – only common theme is that they are small
Most famous, or infamous, microbes _________________
o TB, AIDS, food spoilage
o Minority of microbes are harmful
o Pathogens Æ Microbes that __________________
Most microbes are _____________
o Directly beneficial
ƒ ______________ (bread, yogurt, beer), make _____________ in intestine
o Indirectly beneficial
ƒ ________________ organic matter in soil, clean up sewage, part of food chain
Microbes are everywhere
Naming and classifying microorganisms
• Nomenclature Æ system of naming for organisms
• Based on:
o Latin Æ language of scholars
o _________ names Æ binomial system
ƒ Genus (pl, genera) Æ first name, always ______________
ƒ Specific epithet, species Æ second name, always _____________ case
ƒ Both are written in ______________ (or underlined)
ƒ Staphylococcus aureus, Escherichia coli
ƒ Can be shortened, S. aureus, E. coli
Types of microbes
• Diverse variety of microbes
• Classified into groups that share __________________
o Microbes within groups can also be diverse
o Helps organize microbes
• Bacteria (bacterium)
o Single celled
o _________karyotic
ƒ No _____________
o Most have cell wall Æ made of _______________ (protein and sugar)
o Divide by “_______________________”
o Many swim by using tail called a “flagellum” (pl, flagella)
o Very diverse __________________
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Organic, inorganic, light for food
“Breathe” many different ways
Archaea
o Single celled, _____karyotic
ƒ Cell walls not composed of _______________
o Often found in “_______________” environments
ƒ Hotsprings, salt lakes
o 3 groups
ƒ Methanogens Æ produce ___________
ƒ Extreme halophiles Æ live in extremely _____________ environment
ƒ Extreme thermophiles Æ live in extremely ___________ environment
Fungus (pl, fungi)
o ____karyotic
ƒ Cells have a ______________
o Single celled, multicellular (most)
ƒ Include mushrooms, yeasts, molds
o Cell wall made of ____________
o Absorbing ________________________ from the environment
Protozoan (pl, protozoa)
o Unicellular, eukaryotic
o Move by _______, _______________________________
o Ingesting nutrients through specialized structures “Eating”
o Can be free-living, some are parasites (live inside other organisms)
Alga (pl, algae)
o Eukaryotes that obtain energy from ___________________
o Single celled, multicellular
o Cell wall made of ___________________
o “_________________ producers”
ƒ Produce oxygen and carbohydrates that other organisms are dependent on
Viruses
o Extremely ________________________ particles Æ non-______________
o Parasites Æ live within other cells
o Consists of nucleic acid (_______ or _______) surrounded by a _____________ coat
Multicellular animal parasites
o Eukaryotic
o Parasitic worms called __________________
ƒ Flatworms and roundworms
o Microscopic at some points of their ____________________
Classification of microorganisms
• All organisms classified into groups
o Based on _________________________ cells
o Grouped into 3 “__________________”
1. Bacteria
a. ________karyotic
b. Cell wall contains peptidoglycan
2. Archaea
a. ________karyotic
b. Cell walls, if present, has no peptidoglycan
3. Eukarya – ________karyotic cells, includes:
a. Protists (slime molds, protozoa, algae)
b. Fungi (unicellular yeatss, multicellular molds, mushrooms)
c. Plants (mosses, ferns, conifers, flowers)
d. Animals
Branches of microbiology
• Bacteriology
o Study of ____________
• Mycology
o Study of _____________
• Parasitology
o Study of _________________ and ________________ worms
• Virology
o Study of _____________
• Immunology
o Study of ________________________
• Recombinant DNA technology
o Genetic engineering of microbes for industrial applications
o Employs recombinant DNA
Microbes and human welfare
Only a small proportion of microbes are harmful, or pathogenic. Many more microbes provide
benefits to plants and animals.
• Recycling vital elements
o Microbes recycle important elements between ________ and __________________
o Many elements are in forms not useful to animals
ƒ N2 is _______ of air, completely useless
ƒ Microbes can make it into a form useful for plants and animals
o Carbon, nitrogen, phosphorous, sulfur
• Sewage treatment
o Bacteria degrade excess organic material in sewage
• Bioremediation
o Use of ______________ to clean up __________________
o Detoxify mercury in soil, clean up oil spills
• Insect pest control
o Insects can cause major crop damage
o ___________________ produces toxin that kills many crop pests, such as caterpillars
o Unlike pesticides, don’t have as ____________ on environment as chemicals
• Modern biotechnology
o Use of ________________ for commercial applications
o Used for ____________ for many years
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o ______________________________________ has advanced biotechnology
o ________________ and ________________ produced in bacteria
o Gene therapy Æ curing human disease by “_________________” DNA; uses viruses
o GMO Æ genetically _________________ can increase the yield and quality of crops
Normal microbiota
o We are intimately associated with microbes from birth
ƒ About 10 times more microbes than human cells
o Provide many benefits
ƒ Prevent growth of _______________
ƒ Produce useful substances such as ______________ and _________________
ƒ Help ____________________ harmful pathogens
Infectious diseases
o Microbes do cause disease
o Some are minor Æ colds, flu
o Some can be fatal Æ AIDS, necrotizing fasciitis or “flesh-eating” bacteria