chapter 16 microbial life: prokaryotes and protists –autotrophs, algae, produce food by...

© 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)