1. The Microbial World and You

2. The Microbial World and You
Microorganisms
too small to be seen with unaided eye
“Germ”
rapidly growing cell

3. What are microbes? Fungi (molds, yeasts) mycology Protozoa
parasitology
Microscopic algae
phycology

4. What do they do? Microbes everywhere on your body
Decompose
organic waste
Producers in the ecosystem
by photosynthesis
Produce industrial chemicals
Ethanol and acetone
Produce fermented foods
vinegar, cheese, and bread
Produce manufacturing products
(e.g., cellulase) and treatment (e.g., insulin)
A few are pathogenic,
disease-causing
Microbes everywhere on your body
Microbes— Lactobacillius acidophilus —make yogurt
Others make beer and wine— Saccharaomyces cereviceae

5. The better question might be, “what don’t they do?”
Allows humans to
Prevent food spoilage
Prevent disease occurrence
Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories

6. Did you know? Bacteria causes body odor
Bacteria, tiny as they are, can get sick, too!
Under the right conditions a bacterium like Escherichia coli can grow from just one cell to 1 million cells in less than 7 hours!
How their size compares?

7. How are microbes named and classified?
Linnaeus established
system of scientific nomenclature.
Each organism has two names:
genus and specific epithet.
Are italicized or underlined. The genus is capitalized and the specific epithet is lower case.
Are “Latinized” and used worldwide.
May be descriptive or honor a scientist.

8. Scientific Names Staphylococcus aureus
Describes the clustered arrangement of the cells (staphylo-) and the golden color of the colonies (aur-).
Escherichia coli
Honors the discoverer, Theodor Escherich, and describes the bacterium’s habitat–the large intestine or colon

9. Taxonomy

10. What is systematics? Study of phylogenetic relationships
Phylogenetics = ________
Taxonomy = __________
Also a way of organizing/ classifying
Taxa (taxon—singular)
Systematics: the science oforganizing organisms into groups.
Phylogenetics: ascertaining evolutionary relationships between organisms.
Taxonomy: science of classifying organisms.

11. Look at the background! Plant and Animal Kingdoms Bacteria and fungi
put in the Plant Kingdom
Kingdom Protista proposed
for bacteria, protozoa, algae, and fungi
Prokaryote introduced for cells "without a nucleus“
Prokaryote defined as cells in which nucleoplasm is
not surrounded by a nuclear membrane
Kingdom Fungi
Kingdom Prokaryotae proposed
Two types of prokaryotic cells found

12. How are prokaryotes classified?
Divides prokaryotes into (based on rRNA sequences)
Bacteria
Archaea

13. Who is Carl Woese? Three domains
1978: created current classification scheme
Three domains
Bacteria
Archaea
Eukarya
Protists
Fungi
Plants
Animals

14. What are the key differences between the three domains?
Archaea
Bacteria
Eukarya
Cell type
Cell wall
Organelles/ nucleus?
Sensitive to antibiotic?

15. What is the taxonomy of organisms?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

16. How are eukaryotes classified?
Endosymbiotic theory
Numerous kingdoms, including
Protista
Fungi
Plantae
Animalia

17. What about viruses—How are they classified?
Not included in three domains, which are Virus, viroids and prions
Why not?
Viral species: population of viruses with similar characteristics

18. A closer look at the microbes

19. What are bacteria? Simple, single-celled Prokaryotes
DNA is not inside a membrane
Come in different shapes
Coccus (cocci, plural)
Bacillus (bacilli, plural)
Spiral (corkscrew, comma or curved)
Peptidoglycan cell wall
Binary fission
Some have flagella

20. What are archaea? Also prokaryotes
Cells wall do not have peptidoglycan
Live in extreme conditions
Extreme halophiles
Hyperthermophiles
Methanogens
Not pathogenic
Figure 4.5b

21. What are fungi? Eukaryotes Have a true nucleus wall of chitin
Uni- and multicellular
Includes
Molds
Mushrooms
Yeasts
Slime molds
Sexual and asexual reproduction
Figure 1.1b

22. What are protozoa? Eukaryotes Absorb or ingest organic chemicals
May be motile via pseudopods, cilia, or flagella
Figure 1.1c

23. What are algae? Eukaryotes Cellulose cell walls
Use photosynthesis for energy
Produce molecular oxygen and organic compounds
Figure 1.1d

24. What are viruses? Acellular Consist of DNA or RNA core
Core is surrounded by a protein coat.
Coat may be enclosed in a lipid envelope.
Viruses are replicated only when they are in a living host cell.
Figure 1.1e

25. What are multicellular animal parasites?
Eukaryote
Multicellular animals
Parasitic flatworms and round worms are called helminths.
Microscopic stages in life cycles.
Figure 12.28a

26. What are infectious diseases?
When a pathogen overcomes the host’s resistance, disease results.
Emerging infectious diseases (EID): New diseases and diseases increasing in incidence.
West Nile Virus
Bovine spongiform encephalopathy
Ebola hemorrhagic fever
Hantavirus
AIDS
Anthrax