chapter 16 microbial life: prokaryotes and protists –autotrophs, algae, produce food by...
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© 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko
PowerPoint Lectures for
Campbell Biology: Concepts & Connections, Seventh Edition
Reece, Taylor, Simon, and Dickey
Chapter 16 Microbial Life: Prokaryotes and
Protists
Figure 16.0_1
Figure 16.0_2
Chapter 16: Sections
Prokaryotes Protists
Figure 16.0_3
PROKARYOTES
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Prokaryotic cells are smaller than eukaryotic cells.
The collective biomass of prokaryotes is at least 10
times that of all eukaryotes.
16.1 Diversity
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Figure 16.1
Several hundred species of bacteria live in and on our bodies,
– decomposing dead skin cells,
– supplying essential vitamins, and
– guarding against pathogenic organisms.
Prokaryotes in soil decompose dead organisms, sustaining chemical cycles.
16.1 continued
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Figure 16.2A
Cocci Bacilli Spirochete
Gram stain will stain cell walls with peptidoglycan
– Gram-positive contain peptidoglycan, or
– Gram-negative have less peptidoglycan, and more likely to cause disease.
16.2 External features
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Figure 16.2B
Capsule.
– adhere to substrate or colony and
– protection
16.2 continued
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Figure 16.2C
Capsule
Tonsil cell
Bacterium
– Flagella provide mobility.
– Fimbriae enable prokaryotes to stick to their substrate or each other.
16.2 continued
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Figure 16.2D
Flagella
Fimbriae
Prokaryote population growth
– binary fission,
– can produce a new generation within hours, and
– can generate a great deal of genetic variation
– by spontaneous mutations,
– increasing the likelihood that some members of the
population will survive changes in the environment.
16.3 Adapt rapidly to changes in the environment
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Genome has about one-thousandth as much DNA as a eukaryotic genome and
– one long, circular chromosome packed into a distinct region of the cell.
– additional small, circular DNA molecules called plasmids, replicate independently.
16.3 continued
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Figure 16.3A
Chromosome Plasmids
Endospores form to survive extreme heat or cold.
16.3 continued
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Figure 16.3B
Endospore
Two sources of energy are used.
– Phototrophs capture energy from sunlight.
– Chemotrophs harness the energy stored in chemicals.
Two sources of carbon are used.
– Autotrophs obtain carbon atoms from carbon dioxide.
– Heterotrophs obtain carbon atoms from organic
compounds in other organisms.
16.4 Nutritional diversity
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Figure 16.4
ENERGY SOURCE Sunlight
Photoautotrophs
Oscilliatoria
Photoheterotrophs
Rhodopseudomonas A Bdellovibrio attacking a
larger cell
Chemicals
Chemoautotrophs
Unidentified “rock-eating” bacteria
Chemoheterotrophs
CA
RB
ON
SO
UR
CE
O
rgan
ic c
om
po
un
ds
C
O2
– clog and corrode pipes,
– gum up filters and drains, and
– Coat the hulls of ships.
16.5 Biofilms
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Figure 16.5
Bioremediation is the use of organisms to remove
pollutants from
– soil,
– air, or
– water.
16.6 Prokaryotes help clean up the environment
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Figure 16.6A
Rotating
spray arm
Rock bed coated
with aerobic
prokaryotes
and fungi
Outflow Liquid wastes
Figure 16.6B
– Prokaryotes are classified into two domains:
– Bacteria and
– Archaea.
16.7 Classification
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– Extreme halophiles thrive in very salty places.
– Extreme thermophiles thrive in
– very hot water, such as geysers, and
– acid pools.
16.8 Archaea
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Figure 16.8A
Figure 16.8B
Bacteria is divided into five groups
1. Proteobacteria
– Thiomargarita namibiensis
– is big, uses H2S as energy to fix CO2, produces sulfur wastes.
16.9 Bacteria
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Figure 16.9A
– Rhizobium species that
– root nodules of legumes and
– fix atmospheric nitrogen
16.9 continued
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Figure 32.13B
Shoot
Nodules
Roots
Bacteria within
vesicle in an
infected cell
2. Gram-positive bacteria
– diverse
– soil actinomycetes
– Streptomyces is often cultured by pharmaceutical
companies as a source of many antibiotics.
16.9 continued
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Figure 16.9B
3. Cyanobacteria
– plantlike, oxygen-generating photosynthesis.
– Some fix nitrogen.
– Anabaena
16.9 continued
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Figure 16.9C
Photosynthetic
cells
Nitrogen-fixing
cells
4. Chlamydias
– Chlamydias live inside eukaryotic host cells.
– Chlamydia trachomatis
– is a common cause of blindness in developing
countries and
– most common sexually transmitted disease in the
United States.
16.9 continued
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Figure 16.9D
5. Spirochetes are
– helical bacteria and
– some pathogens
– syphilis and
– Lyme disease.
16.9 continued
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Figure 16.9E
– Exotoxins are proteins secreted into their environment.
– Staphylococcus aureus
– Endotoxins are components of the outer membrane of
gram-negative bacteria.
16.10 Disease
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Figure 16.10
PROTISTS
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Protists
– mostly unicellular eukaryotes,
– refer to eukaryotes that are not
– plants,
– animals, or
– fungi.
16.13 Diversity
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Nutrition
– autotrophs, algae, produce food by photosynthesis,
– heterotrophs, protozoans, eat bacteria and other
protists,
– heterotrophs, parasites, survive on a living host, and
– mixotrophs, use photosynthesis and heterotrophy.
16.13 continued
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Figure 16.13A
Autotrophy Heterotrophy
Caulerpa, a green alga Giardia, a parasite
Mixotrophy
Euglena
Habitats include
– anywhere there is moisture and
– the bodies of host organisms.
16.13 continued
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Five monophyletic supergroups.
16.13 continued
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Primary endosymbiont theory explains mitochondria
and chloroplasts.
– Eukaryotic cells evolved when prokaryotes established
residence within other, larger prokaryotes.
– Mitochondria and chloroplasts
– structural and molecular similarities to prokaryotic
cells and
– replicate and use their own DNA, separate from the
nuclear DNA of the cell.
16.14 Secondary endosymbiosis
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Figure 16.14_s1
Primary
endosymbiosis
Cyanobacterium
Evolved into
chloroplast
Nucleus
Heterotrophic
eukaryote
2
1
Figure 16.14_s2
Primary
endosymbiosis Green alga
Chloroplast
Cyanobacterium
Evolved into
chloroplast
Nucleus
Heterotrophic
eukaryote
Chloroplast Red alga
Autotrophic
eukaryotes
3
2
1
Figure 16.14_s3
Primary
endosymbiosis Green alga
Chloroplast
Cyanobacterium
Evolved into
chloroplast
Nucleus
Heterotrophic
eukaryote
Chloroplast Red alga
Autotrophic
eukaryotes
Heterotrophic
eukaryotes
4 3
2
1
Secondary endosymbiosis is
– the process in which an autotrophic eukaryotic protists
were engulfed
– key to protist diversity.
16.14 continued
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Figure 16.14_s4
Primary
endosymbiosis Green alga
Chloroplast
Cyanobacterium
Evolved into
chloroplast
Nucleus
Heterotrophic
eukaryote
Chloroplast Red alga
Autotrophic
eukaryotes
Heterotrophic
eukaryotes
Secondary
endosymbiosis
4 3
2
1
5
Figure 16.14_s5
Primary
endosymbiosis Green alga
Chloroplast
Cyanobacterium
Evolved into
chloroplast
Nucleus
Heterotrophic
eukaryote
Chloroplast Red alga
Autotrophic
eukaryotes
Heterotrophic
eukaryotes
Euglena
Remnant of
green alga
Secondary
endosymbiosis
4 3
2
1
5
Chromalveolates include
– diatoms, unicellular algae with a glass cell wall
containing silica,
16.15 Chromalveolates
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Figure 16.15A
– Dinoflagellates,
– unicellular autotrophs, heterotrophs, and mixotrophs that are
common components of marine plankton,
16.15 continued
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Figure 16.15B
– Brown algae,
– large, multicellular autotrophs
16.15 continued
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Figure 16.15C
– Water molds,
– unicellular heterotrophs,
16.15 continued
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Figure 16.15D
– Ciliates,
– unicellular heterotrophs and mixotrophs that use
cilia to move and feed,
16.15 continued
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Figure 16.15E
Mouth
Foraminiferans
– oceans and fresh water,
– porous shells, tests, of calcium carbonate,
– pseudopodia used in feeding and locomotion.
16.17 Rhizarians
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Figure 16.17A
Radiolarians
– mostly marine
– mineralized internal skeleton of silica.
16.17 Rhizarian
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Figure 16.17B
– Modified mitochondria lack electron transport
chains and
– anaerobic pathways,
– glycolysis
Termite gut, digest celluose
16.18 Excavata
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Figure 16.13B
– Mixotrophs
– Euglena
16.18 Excavata
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Figure 16.13A_3
Mixotrophy
Euglena
Waterborne parasite
Giardia intestinalis,
16.18 Excavata
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Figure 16.13A
Autotrophy Heterotrophy
Caulerpa, a green alga Giardia, a parasite
Mixotrophy
Euglena
Figure 16.18A
Flagella
Undulating
membrane
Figure 16.18B
Lobe-shaped pseudopodia
– free-living amoebas,
– parasitic amoebas, and
– slime molds.
16.19 Unikonta
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Figure 16.19A
Figure 16.19B
Figure 16.19C
– red algae,
– green algae, and
– land plants.
16.20 Archaeplastida
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Figure 16.20A
Figure 16.20B
Volvox Chlamydomonas
Ulva, sea lettuce
– multicellular green alga
– alternation of generations
16.20 Archaeplastida
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Figure 16.20C_s1
Mitosis
Spores
Mitosis
Female
gametophyte
Gametes
Male
gametophyte
Key
Haploid (n)
Diploid (2n)
Figure 16.20C_s2
Mitosis
Spores
Mitosis
Female
gametophyte
Gametes
Male
gametophyte
Fusion of
gametes
Zygote
Key
Haploid (n)
Diploid (2n)
Figure 16.20C_s3
Mitosis
Spores
Meiosis
Mitosis
Female
gametophyte
Gametes
Male
gametophyte
Fusion of
gametes
Zygote Sporophyte
Mitosis Key
Haploid (n)
Diploid (2n)
Eukaryotic cell led to an evolutionary radiation
Unicellular protists more diverse than prokaryotes.
16.21 Multicellularity
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– Multi: Specialized cells
– Uni: All activities in single cell.
16.21 Multicellularity
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– brown algae,
– fungi and animals
– red algae and green algae
16.21 Multicellularity
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Figure 16.21A
Key
Animals
Choanoflagellates
Fungi
Nucleariids
Land plants
Amoebozoans
Charophytes
Other green algae
Red algae
Gre
en
alg
ae
Arc
ha
ep
lastid
s
Un
iko
nts
An
cestra
l eu
kary
ote
All unicellular
Both unicellular
and multicellular
All multicellular
Figure 16.21B
Nucleariids
Fungi
1 billion
years ago
Choanoflagellates
A nucleariid, closest living
protistan relative of fungi
Individual
choanoflagellate
Colonial
choanoflagellate
Animals
Sponge
Sponge
collar cell
Figure 16.UN01
Nutritional mode Energy source Carbon source
Photoautotroph Sunlight
Chemoautotroph
Photoheterotroph
Chemoheterotroph
Inorganic chemicals
Sunlight
Organic compounds Organic compounds
CO2
1. Describe the structures and functions of the diverse
features of prokaryotes; explain how these features have
contributed to their success.
2. Explain how populations of prokaryotes can adapt rapidly
to changes in their environment.
3. Describe the nutritional diversity of prokaryotes and explain
the significance of biofilms.
4. Explain how prokaryotes help clean up the environment.
5. Compare the characteristics of the three domains of life;
explain why biologists consider Archaea to be more closely
related to Eukarya than to Bacteria.
Quiz
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6. Describe the diverse types of Archaea living in extreme
and moderate environments.
7. Distinguish between the subgroups of the domain
Bacteria, noting the particular structure, special features,
and habitats of each group.
8. Distinguish between bacterial exotoxins and endotoxins,
noting examples of each.
9. Describe the steps of Koch’s postulates and explain why
they are used.
10. Explain how bacteria can be used as biological weapons.
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11. Describe the extremely diverse assortment of eukaryotes.
12. Explain how primary endosymbiosis and secondary
endosymbiosis led to further cellular diversity.
13. Describe the major protist clades noting characteristics
and examples of each.
14. Describe the life cycle of Ulva, noting each form in the
alternation of generations and how each is produced.
15. Explain how multicellular life may have evolved in
eukaryotes.
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Figure 16.UN03
Red algae
Other green algae
(b)
Land plants
Amoebozoans
Nucleariids
(d)
(e)
(f)
Gre
en
alg
ae
An
cestra
l eu
kary
ote
(a)
(c)