Transcript Lab 1 Introduction

Figure 1.2 Anton van Leeuwenhoek’s microscopic observations.
Lens
Location of specimen
on pin
Specimen-positioning
screw
Focusing control
Stage-positioning screw
Van Leeuwenhoek using his
microscope
Microscope
replica
From 1683
Drawings of bacteria
Types of Microorganisms
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Bacteria
Archaea
Fungi
Protozoa
Algae
Viruses
Multicellular animal parasites
• Taxonomy = classification system
• Linnaeus classification system based upon
structural similarities between species.
• Modern classification system based upon
evolutionary relationships (determined by
DNA sequencing).
• Traditional (including lab manual for 101):
Red, brown and green algae are in the Plant
kingdom
• Textbook for 101: Red, brown, and green
algae are in the Protista kingdom
• UC Berkeley: Red, brown and green algae are
in separate kingdoms. (The Protista kingdom
does not exist.)
Classification categories
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domain – a group of related kingdoms
kingdom - a group of related phyla
phylum (plural = phyla) - a group of related classes.
class - a group of related orders
order - a group of related families
family - a group of related genera
genus (plural = genera) - a group of related species
species - a kind of living organism . All organisms who
can potentially reproduce together under natural
conditions and produce fertile offspring.
Most basic cell types:
Prokaryotic: small, simple cells which lack a
nucleus and other cell structures
Eukaryotic cells contain a nucleus and internal
structures
3 Domains
1. Bacteria (prokaryotic)
– Includes blue-green algae
2. Archaea (prokaryotic)
3. Eukarya
– The Eukarya are divided into more than 10
Kingdoms: Plants, Fungi, Animals and many
others
Figure 10.1 The Three-Domain System.
Eukarya
Bacteria
Origin of chloroplasts
Animals
Fungi
Origin of mitochondria
Amebae
Mitochondria
Slime molds
Cyanobacteria
Proteobacteria
Chloroplasts
Archaea
Methanogens
Plants
Extreme
halophiles
Ciliates
Green
algae
Dinoflagellates
Diatoms
Hyperthermophiles
Gram-positive
bacteria
Euglenozoa
Giardia
Thermotoga
Horizontal gene transfer
occurred within the
community of early cells.
Mitochondrion degenerates
Nucleoplasm grows larger
(DON’T NEED TO KNOW DETAILS)
(DON’T NEED TO
KNOW DETAILS)
UC Berkeley Museum of Paleontology 2011: The 12 kingdoms of eukaryotes
Bacteria (a domain)
• Prokaryotes
• Peptidoglycan cell walls
• For energy, use organic chemicals or
inorganic chemicals or photosynthesis
(cyanobacteria = blue-green algae)
Archaea (a domain)
• Prokaryotic
• Lack peptidoglycan
• Some but not all live in extreme
environments. These include
methanogens, extreme halophiles, and
extreme thermophiles
Fungi (a kingdom)
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Eukaryotes
Chitin cell walls
Use organic chemicals for energy
Most are multicellular (molds and
mushrooms) but some are unicellular
(yeasts)
Protozoa (not a modern scientific
category – includes multiple kingdoms)
• Eukaryotes
• Absorb or ingest organic chemicals
• May be motile via pseudopods, cilia, or
flagella
Eukaryotic Algae (not a modern scientific
category – includes multiple kingdoms)
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Eukaryotes
Cellulose cell walls
Use photosynthesis for energy
Produce molecular oxygen and organic
compounds
Viruses
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Acellular
Consist of DNA or RNA core
Core is surrounded by a protein coat
Coat may be enclosed in a lipid envelope
Are replicated only when they are in a
living host cell
Multicellular Animal Parasites
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Eukaryotes
Multicellular animals
Flatworms and roundworms
Microscopic stages in life cycles
Microbes in Our Lives
• A few are pathogenic (disease-causing)
• Decompose organic waste
• Many are photosynthetic: produce organic
molecules and oxygen, which are used by
animals
• Produce industrial chemicals such as ethanol,
acetone and many others
• Produce fermented foods such as cheese,
bread, wine and vinegar
Fermentation
• Pasteur showed that microbes are
responsible for fermentation
• Some but not all fermentation converts
sugar to alcohol
• Microbial growth is also responsible for
spoilage of food
Normal Microbiota
• Microbes normally present in and on the
human body are called resident flora or
normal microbiota
• Normal microbiota help to prevent growth
of pathogens
• Normal microbiota produce growth factors,
such as folic acid and vitamin K
Figure 1.7 Several types of bacteria found as part of the normal microbiota on the surface of the human tongue.
© 2013 Pearson Education, Inc.
Naming Microorganisms
• Linnaeus established the system of
scientific nomenclature
• Each organism is identified by two names:
the genus and species
Homo sapiens
Canis familiaris
Scientific Names
• Are italicized or underlined
– The first letter of the genus name is
capitalized; the species name is not
• Are “Latinized” and used worldwide
• May be descriptive or honor a scientist
Escherichia coli
• Honors the discoverer, Theodor Escherich
• Describes the bacterium’s habitat—the
large intestine, or colon
Staphylococcus aureus
• Describes the clustered (staphylo-)
spherical (cocci) cells
• Describes the gold-colored (aureus)
colonies
Scientific Names
• Scientific names may be abbreviated with
the first letter of the genus and the species
name: E. coli and S. aureus
(DON’T NEED TO KNOW DETAILS)
• Which is a correct scientific name?
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Baker’s yeast
Saccharomyces cerevisiae
Saccharomyces cerevisiae
S. cerevisiae
The Germ Theory of Disease
• 1876: Robert Koch proved that a
bacterium causes anthrax and provided
the experimental steps, Koch’s
postulates, to prove that a specific
microbe causes a specific disease
• An opportunist is a bacteria that does not
normally cause a disease, but can become
pathogenic under certain conditions, such as
immunosuppression
• Nosocomial infection: spread in a hospital or
similar location