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Main Themes in Microbiology Chapter 1 Humans are outnumbered We have ~ 10 trillion cells in our body –We have 100 trillion foreign cells in/on our body!!

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Presentation on theme: "Main Themes in Microbiology Chapter 1 Humans are outnumbered We have ~ 10 trillion cells in our body –We have 100 trillion foreign cells in/on our body!!"— Presentation transcript:


2 Main Themes in Microbiology Chapter 1

3 Humans are outnumbered We have ~ 10 trillion cells in our body –We have 100 trillion foreign cells in/on our body!! –Tiny life forms are called microorganisms

4 What is a microorganism? Could be… –Bacteria –Viruses –Protists Protozoa and algae –Helminthes Worms

5 What is microbiology? Microbiology is a special area of biology that deals with tiny life forms not readily observed without magnification –Little guys are called: Microorganisms Microbes Germs Bugs

6 Can I do this for a living? Geomicrobiologist- roles of microbes in the development of the earth’s crust

7 Marine microbiologist- study the oceans and its smallest inhabitants

8 Medical technologists- do tests to diagnose pathogenic microbes and their diseases

9 Nurse epidemiologists- analyze the occurrence of infectious diseases in hospitals

10 Astrobiologist- study the possibility of organisms in space

11 What do we focus on? Genetics Physiology –Appearance and survival + and – characteristics Environmental interaction Host interaction Uses in industry/agriculture

12 How long have these guys been around? Practically forever! –Life on Earth started 3.5 billion years ago! Prokaryotes came first Then eukaryotes


14 Good or bad? Both! We’ve been using microorganisms for thousands of years!

15 Good Microbes Yeast (microscopic fungi) = bread Penicillin (moldy bread) = first aid

16 Biotechnology Industry applications –Bacteria that can mine metals!

17 Genetic Engineering Manipulates genetics to make new products and genetically modified organisms –Microbes can make drugs, hormones, and enzymes


19 Bioremediation Fixing environmental problems with microorganisms

20 Bad Microbes Pathogens- agents that cause disease –Over 2000 types of microbes that cause disease! –WHO says over 10 BILLION infections caused by microbes worldwide


22 Bad microbes Malaria –Actually a microbe (protist)

23 Malaria Prevention Malaria nets cost $3-5 1/3 world population makes <$1/day Which kid will sleep under the net tonight?

24 The subtle side of microbes Gastric ulcers –Heliobacter Cancer –HPV –Hepatitis viruses Diabetes –coxsackievirus schizophrenia MS OCD Coronary artery disease Infertility –Chlamydia Associated with

25 General Microbe Characteristics TINY Millimeters (mm), micrometers (µm), and nanometers (nm)


27 Prokaryotic or eukaryotic

28 1 or a few cells

29 Free-living—live independently Parasitic—microbes harbored and nourished inside host

30 Could be viruses –NOT ALIVE –NOT CELLS –Small amount of hereditary material wrapped up in a protein coating –“Obligate intracellular parasites”

31 * Viroids are smaller viruses

32 Adenovirus

33 Rhinovirus


35 Where does life come from? Meat makes maggots

36 Shrooms spring from spruce

37 Rats from rotting refuse

38 Spontaneous Generation The idea that life can arise from non-living matter –Aka abiogenesis Competing theory—biogenesis –Life can only arise from living things of a similar nature

39 How can we prove or disprove this hypothesis? Francesco Redi (1668) Hypothesis: Flies produce maggots on meat. Lay small eggs Set up a controlled experiment to test his hypothesis Found that by keeping flies away from meat, no maggots appear

40 Variables 1.Controlled variable: Jar, meat, location, temperature, time 2.Independent or Manipulative variable: Gauze covering the meat jars 3.Dependant (responding) variable: Whether maggots appear

41 John Needham – 1745 Hypothesis: spontaneous generation occurs under the right conditions –Boiled chicken broth and then sealed flask (thought heat would kill) –“Animalcules” swarmed after a few days –Therefore, he felt his hypothesis was right.

42 What was wrong with Needham’s hypothesis? Was it flawed? He assumed all the animalcules would be killed by heat

43 Louis Jablot Hypothesis: even microscopic organisms must have parents Boiled hay infusions very similar to Needham’s work However, his uncovered WAS contaminated with growth


45 Lazzaro Spallanzani 1776 Attempted to disprove Needham’s work. Took 4 flasks with broth in them –Left open – went cloudy –Sealed but not boiled – went cloudy –Boiled but left open – went cloudy –Sealed then boiled – stayed clear Microbes were not found in this one but in all the other ones

46 What would have been Spallanzani’s hypothesis? Microorganisms form not from air but from other microorganisms. When broth was boiled and then sealed, no air could get in for organisms to reproduce.

47 What was wrong with what Spallanzani assumed? No air

48 Louis Pasteur - 1859 Tested Spallanzani’s work by using a curved neck flask to prevent microbes from entering flask but would let air in Boiled broth of control and experimental flasks. Result: No growth in curved neck flask. Microbes collecting in bend

49 Pasteur’s broth in the curved necked flask stayed sterile for years until he tilted it and the airflow carried the microbes into the broth

50 Conclusion Contamination is due to microbes in the air. Spontaneous generation theory died here!!

51 John Tyndall Heated hay infusions for various times. Found 2 kinds of bacteria – 1. Those readily killed by heating 2. Heat resistant forms (endospores) **Between 1875 – 1918, most of the disease-causing bacteria were identified.

52 The Microscope Antonie von Leeuwenhoek

53 The Microscope Leeuwenhoek looked at a drop of water and saw moving things Called them “animacules” Bacteria and protozoa

54 The Pillar of Science: The scientific method Origin in the 1600s…enough of the superstition!!

55 The Scientific Method 1.Ask a question Do some research 2.Propose a hypothesis 3.Conduct a controlled experiment 4.Collect data and make observations 5.Analyze data 6.Make a conclusion 7.Possibly, write a theory

56 Scientific method NEEDS a testable hypothesis Use the deductive approach ▫If…then (because) Test, test, and retest that hypothesis!


58 Do you know where bees come from? Recipe for Bees 1.Kill a bull during the first thaw of winter 2.Build a shed 3.Place the dead bull on branches and herbs inside the shed 4.Wait for summer. The decaying body of the bull produces bees Words from a Roman poet about 2000 years ago

59 Know the jargon Hypothesis- tentative explanation for what has been observed Theory- very well supported idea Many hypotheses and experiments NOT A “FACT Law- principle of science Super accurate

60 Germ theory of disease Louis Pasteur ◦ Human diseases could arise from infection Robert Koch ◦ Koch’s Postulates  Verified germ theory  Showed anthrax caused by bacterium


62 Aseptic Technique Joseph Lister Goal: reduce microbes in a medical setting and preventing wound infections ◦ No handwashing prior to surgery before Lister!!

63 Taxonomy What’s in a name?

64 Taxonomy- formal system for organizing, classifying, and naming organisms Carl von Linnie Aka Carolus Linnaeus Standardized Keeps names short and consistent Binomial system of nomenclature

65 a two name system for writing scientific names. The genus name is written first (always Capitalized). The species name is written second (never capitalized). Both words are italicized if typed or underlined if hand written. Example: Smith john (print) Smith john (written) Felis concolor or F. concolor Which is the genus? The species? Binomial Nomenclature

66 The major classification levels, from most general to most specific (several of these have subdivisions) A group at any level is a taxon.

67 Kingdoms are divided into groups called phyla Phyla are subdivided into classes Classes are subdivided into orders Orders are subdivided into families Families are divided into genera Genera contain closely related species Species is unique Categories within Kingdoms



70 Phylogeny Natural relatedness of organisms Related by evolution—theory that all life descended, with modification, from one common ancestor

71 Evidence Morphology- similar structures in organisms Physiology- similar functions of organisms Genetics- similar DNA in organisms

72 Dumpy Kings Play Cards On Fat Green Stools Domain Kingdom Phylum Class Order Family Genus Species


74 Kingdoms and Domains Originally, 2 kingdoms Plantae and Animalia Then 3 (Protista) …and 4 (Add the Bacteria— kingdom Monera) …finally 5 (Fungi!)

75 5 kingdom system Associated with Robert Whittaker Based on the morphology and physiology-type of evidence


77 The domain system Now we look at molecular biology How do DNA, proteins, rRNA compare? Bacteria Kingdom split into two: Domain Bacteria Domain Archaea

78 3 domain system Domain eukarya— the eukaryotes Domain archaea— prokaryotes that live in extreme environments Domain bacteria— “traditional” prokaryotes


80  What is classification?  Why is classifying living things important?  What is taxonomy?  Describe binomial nomenclature.

81  Who developed a system for naming living organisms?  What is a scientific name of an organism and how is it written?

82  Kingdom  Phylum  Class  Order  Family  Genus  Species

83  What are the seven classification groups?  Kings Play Cards On Fat Green Stools

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