microbiology chapter 1 lect(2)
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The Science of MicrobiologyClassification of Organisms
Chapter 1
Microbiology
Liberty Senior High
Mr. Knowles
Two Main Forms of Cells• All cells share certain characteristics
–They are all enclosed by a membrane
–They all use DNA as genetic information
• There are two main forms of cells:
–Eukaryotic
–Prokaryotic
• Prokaryotic cells– Lack the kinds of membrane-enclosed
organelles found in eukaryotic cells.EUKARYOTIC CELL
Membrane
Cytoplasm
Organelles
Nucleus (contains DNA)1 µm
PROKARYOTIC CELL
DNA
(no nucleus)
Membrane
Figure 1.8
• Unicellular organisms that lack a nucleus and membrane-bound organelles
• Unique flagella (flagellin), no cilia
• Bacteria and Archaea Domain
• Have DNA and cell membranes
Prokaryotic Cells
Bacterial Flagellum
Flagellin Protein
Eukaryotic Cells• Uni- and multicellular organisms with a
nucleus and organelles• Have a 9 + 2 arrangement of
microtubules to make flagella or cilia• Animalia, Plantae, Fungi, Protista• Have DNA and cell membrane
9 + 2 System of Eukaryotes• All eukaryotes with cilia or flagella, build it the
same way.
Cilia of Paramecium.The cilia of Parameciumpropel the cell throughpond water.
Cross section of cilium, as viewedwith an electron microscope
15 µm
1.0 µm
5 µm
Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by moving a film of debris-trapping mucus upward.
Figure 1.16
9 + 2 arrangement of microtubules
• Classifying lifeSpecies Genus Family Order Class Phylum Kingdom Domain
Mammalia
Ursusameri-canus(Americanblack bear)
Ursus
Ursidae
Carnivora
Chordata
Animalia
EukaryaFigure 1.14
• Life’s three domains
Figure 1.15
100 µm
0.5 µm
4 µmBacteria are the most diverse and widespread prokaryotes and are now divided among multiple kingdoms. Each of the rod-shapedstructures in this photo is a bacterial cell.
Protists (multiple kingdoms)are unicellular eukaryotes and their relatively simple multicellular relatives.Pictured here is an assortment of protists inhabiting pond water. Scientists are currently debating how to split the protistsinto several kingdoms that better represent evolution and diversity.
Kingdom Plantae consists of multicellula eukaryotes that carry out photosynthesis, the conversion of light energy to food.
Many of the prokaryotes known as archaea live in Earth‘s extreme environments, such as salty lakes and boiling hot springs. Domain Archaea includes multiple kingdoms. The photoshows a colony composed of many cells.
Kindom Fungi is defined in part by thenutritional mode of its members, suchas this mushroom, which absorb nutrientsafter decomposing organic material.
Kindom Animalia consists of multicellular eukaryotes thatingest other organisms.
DOMAIN ARCHAEA
The Three Domains of Life• At the highest level, life is classified into three domains:
– Bacteria– Archaea– Eukarya
• Domain Bacteria and domain Archaea– Consist of prokaryotes
• Domain Eukarya, the eukaryotes– Includes the various protist kingdoms (Protista) and the
kingdoms Plantae, Fungi, and Animalia
Bacteria Domain• Unicellular, Prokaryotic• Cell Wall- made of peptidoglycan• Cell Membrane- unbranched fatty chains• Sensitive to antibiotics (different kind of
ribosome)• Circular Chromosome• Cannot tolerate extreme temperatures. (>
100˚ C)
Archaea Domain• Unicellular, Prokaryotic
• Cell Wall- no peptidoglycan.
• Cell Membrane- branched fatty chains.
• Not sensitive to antibiotics (different kind of ribosome)
• Circular Chromosome
• Grow in extreme environ. (Extremophiles- thermophiles and halophiles)
Show me the “ancient bacteria”- Kingdom Archaebacteria.
Video: Intimate Strangers- The Tree of
Life.
Eukarya Domain• Uni- and multicellular, Eukaryotic
• Cell Wall- no peptidoglycan (cellulose or chitin)
• Cell Membrane- unbranched fatty chains.
• Not sensitive to antibiotics (different ribosomes)
• Linear Chromosomes
• Cannot grow in extreme temps. (> 100˚ C)
Bacteria Kingdom• Unicellular, Prokaryote
• Peptidoglycan Cell Wall
• Nutrition- Autotroph and Heterotrophic
• Motility- may have bacterial flagella
• Asexual Reprod. And Conjugation
• No nervous system
• Examples: E. coli, Salmonella, etc.
Archaea Kingdom• Unicellular, Prokaryote
• No peptidoglycan in cell wall, muramic acid
• Nutrition- Autotrophic and Heterotrophic
• Motility- Different Kind of Bacterial Flagella
• Asexual Reprod. And Conjugation
• No nervous system
• Examples: Methanogens, halophiles, and thermophiles
Protista Kingdom• Mostly Uni- but some multicellular Eukaryotes
• Various Types of Cell Wall, no peptidoglycan
• Nutrition- Autotrophic and Heterotrophic
• Motility- (9 + 2) Cilia or flagella
• Meiosis and Fertilization
• Nervous system- primitive conduction of some stimuli (light, heat, etc.)
• Ex. : Paramecia, Amoeba, Euglena
Fungi Kingdom• Mostly multi, some unicellular Eukaryotes• Chitin Cell Wall• Nutrition- Heterotrophic• Nonmotile• Meiosis and Fertilization• No nervous system• Ex.: molds, mushrooms, mildew
Animalia Kingdom• Multicellular, Eukaryote
• No cell wall
• Nutrition- Heterotrophic
• Motility- (9 + 2) Cilia or flagella
• Meiosis and Fertilization
• Primitive and complex nervous systems
• Ex. : worms, fish, birds, YOU!
Plantae Kingdom• Multicellular Eukaryote
• Cell Wall – Cellulose
• Nutrition – Autotroph
• Most cells are nonmotile, but some make reproductive cells that have (9 + 2) flagella
• Meiosis and Fertilization
• No nervous system
• Meiosis and Fertilization
• Ex. : Trees, shrubs, Venus Fly Trap!
How Do We Group Microorganisms?Into Four Kingdoms:• Protista- protists and algae (many Kingdoms)• Fungi- yeast and other fungi• Eubacteria- “true” bacteria (many Kingdoms) • Archaebacteria- “ancient” bacteria (many Kingdoms)
In its own Group:• Viruses
Question of the Day!
Who was the first microbiologist?
Holy Moses!• Instructed people to
bury feces and other wastes.
• Bible also refers to isolating lepers. (Deuteronomy, Ch. 13)
Hippocrates• Greek physician in 400
B.C. who established medical ethics.
• Linked symptoms to certain diseases.
• Realized diseases could be transmitted by clothing.
Bubonic Plague (Black Death)
• 542-1600’s, spread into Europe by caravan and sea trading routes.
• Carried by fleas on ship rats.
Xenopsylla cheopis
Show me more of the Black Death!
Video: Secrets of the Dead- The Mystery of the
Black Death
Bubonic and Septicemic Plague
The First Case of Biological Weapons? Caffa
Flagellism and Anti-Semitism
Robert Hooke
• In 17th Century, built the first microscope.
• Used the term “cell” to describe what he saw--after the small rooms of monks.
Hand-drawn images from Micrographia, published in 1665, Robert Hooke
Hooke’s First Microscope
Anton von Leewenhoek
Leewenhoek• From 1632-1723, he
designed microscopes.• Described “animalcules”• Never sold his
microscopes, microbiology didn’t advance for 100 yrs.
Schleiden and Schwann
• Formulated the Cell Theory- that cells are the fundamental units of all life.
Germ Theory
• Mid-19th Century: Microorganisms can invade other organisms and cause disease.
Spontaneous Generation• Belief that life arose from nonliving
things, a “vital force” found in the air.• Ex: Broth turning cloudy happened
spontaneously from nonliving material.• Ex: Rags rats
Meat maggots.
Francesco Redi, 1626-1697•1668, first controlled, experiment to disprove spontaneous generation. Rotten meat experiment refutes abiogenesis.
Francesco Redi• Disproved
spontaneous generation with the fly and rotting meat experiment.
John Needham, 1713-1781
• First Catholic clergyman to become a member of the Royal Society of London.
•1754, boiled chicken broth and put it into a flask and sealed it. Saw growth.
Needham and “Vital Atoms”• Needham and Georges Comte de
Buffon proposed “vital atoms” cause life.
• They could be seen in pond water and infusions.
• “Vital atoms” escape dying organic material and move into the soil or water to be taken up the the plants.
Lazzaro Spallanzani, 1729-1799•Italian priest who suggested that the microbes entered the broth from the air after boiling.
•In 1765, he describes another experiment to test if microbes appear spontaneously.
Needham and others vitalists reply…
• Argue the experiment only proves that spontaneous generation requires air.
• Need the “vital force.”
• Even Spallanzani agrees in some cases- regeneration and other cases of microbes.
Salamander Limb Regeneration
Retrieved from http://darwin.bio.uci.edu/~mrjc/, September 28, 2004
What Spallanzani Might Have Seen!
Retrieved from http://darwin.bio.uci.edu/~mrjc/, September 28, 2004
Louis Pasteur
Pasteur and Tyndall
• In the mid-1800’s, disproved spontaneous generation using experiments with “swan-necked” flasks--allowed the air with the “vital force” to enter.
Pasteur’s Swan-necked Flask Experiment
Pasteur and the Swan-Necked Flask
Louis Pasteur• From 1822-1895• Developed pasteurization technique
of heating wine to kill other microorganisms without killing yeast.
• Developed first rabies vaccine- from rabbit spinal cord
Robert Koch
Robert Koch
• Developed techniques for isolating bacteria and growing in vitro (out of the body)
• Developed different medias for growing cultures.
Koch’s PostulatesStep 1.
Step 2.
Step 3.
Step 4.
Koch’s Postulates
1.) The specific pathogen (disease-causing) organism must be found in all cases of the disease.
2.) The pathogen must be isolated.
Koch’s Postulates
3.) Must inoculate a healthy animal with the pathogen and cause the disease.
4.) Must recover the same pathogen from the inoculated animal.
Still use Koch’s Postulates Today!
The Story of Lyme Disease-Borrelia burgdorferi
Video: Parasites-The Body Snatchers, #96
Ignaz Semmelweis-The Father of Sanitary Practices
Ignaz Semmelweis• 1800’s, Autopsy to child birth;
puerperal (childbed) fever.
• Encouraged sanitary practices by physicians.
• Ridiculed, had a nervous breakdown, asylum and died of an infection.
Joseph Lister• Developed
aseptic technique for surgeons
• Used carbolic acid to sterilize instruments.
The First Vaccines Came Out of an Epidemic!
The Story of Smallpox
Video: Plagues: The Smallpox Curse, #36
Smallpox Skin Lesions
How Do We Protect Ourselves? Immunology
• Ancient Chinese- inhaled ground smallpox scabs--develop a mild case of smallpox but survive later exposure.
Smallpox and Edward Jenner• In late 1100’s, smallpox had been carried
back to Europe with the Crusaders from the Near East.
• Late 1700’s, Jenner realized milkmaids with cowpox did not get smallpox.
• First “tested” vaccine (vacca means cow) against smallpox.
Sarah Nelmes- Cow Pox Lesion and James Phipps
Edward Jenner- Ethics are Relative?
Eli Metchnikoff• In the 1880’s,
discovered that the human body has cells which can ingest microbes.
• Called them phagocytes or “cell-eating.”
Virology and Beijerinck• Called microbes
that could pass through filters “viruses.”
• Established that they needed host cells for their own replication.
Viruses and Cancer• Rous discovered that
certain viruses can cause cancer.
• Won the Nobel Prize in 1966. Human PapillomaVirus- warts and cervical cancer.
Viruses and Cancer
• Human Hepatitis B virus
• Can cause liver cancer.