How Life Started

Early Earth

spontaneous formation of lipids,carbohydrates, amino acids, proteins,nucleotides under abiotic conditions

livingcells

self-replicating system enclosed in aselectively permeable, protective lipid sphere

DNA RNA enzymes andother proteins

formation ofprotein-RNA systems,

evolution of DNA

formation oflipid spheres

membrane-bound proto-cells

to vacuum pump

boiling water

sparkdischarge

liquid water in trap

water containingorganic compounds

water droplets

water in

condenser

electrodes

water out

CH4

NH3

H2OH2

gases

Figure 14.4(1)Page 224

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3.8 3.2 2.5

Cyclic pathway ofphotosynthesis

Noncyclic pathwayof photosynthesis

Aerobic respiration

Origin ofProkaryotes

Eubacterial Lineage

Ancestors of Eukaryotes

ArchaebacterialLineage

billion years ago

origins of eukaryotes

origins of animals

origins of fungi

origin of mitosis, meiosis

endosymbiotic origins of mitochondria

endosymbiotic origins of chloroplasts

1.2billion years

ago

900million years

ago

435million years

ago

ARCHAEBACTERIAExtreme halophilesMethanogensExtreme thermophiles

EUKARYOTESAnimals

Heterotrophic protistans

Fungi

Photosynthetic protistans

Plants

EUBACTERIAOxygen-producing

photosynthetic eubacteria

Other photosynthetic

eubacteria

Heterotrophic and

chemoautotrophic eubacteria

origins of plants

Photosynthetic protistans

plasma membrane

cell wallouter capsule

pilus

bacterial flagellum

cytoplasm with ribosomes DNA in nucleoid

coccus bacillus

spirillum

Bacterium beforeDNA replication

DNA replicationcompleted

DNA replicationbegins

Stepped Art

Membrane growth movesDNA molecules apart

New membrane andcell-wall material deposited

Cytoplasmdivided in two

spirochetes

chlamydias

proteobacteria

Gram-positive bacteria

to ancestors ofeukaryotes

cyanobacteria

molecular origin of life

extremethermophiles

methanogensextreme

halophiles

ARCHAEBACTERIA

EUBACTERIA

Representative habitat for methanogens

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Representative habitat for extreme thermophiles

Representative habitat for extreme halophiles

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Figure 14.8dPage 228

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Figure 14.10bPage 229

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Spirochete that causes Lyme disease

Deer ticks Typical rash

Figure 14.11Page 229

Endospore developing inside a cell of Clostridium tetani

spore coat

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Figure 14.12Page 230

Berkeley Pit Lake

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In-text FigurePage 230

Figure 14.13Page 231

branch leading to plants

brown algae

chrysophytes

oomycotes

Stramenopiles

charophytes

green algae

red algae

slime molds

parabasalids(e.g., Trichomonas)

diplomonads(e.g., Giardia)

endosymbiotic origins from prokaryotic

ancestors

amoeboid protozoans

“crown” of eukaryotes (rapid divergences)

branch leading to fungi

branch leading to animals

Alveolates

ciliates

sporozoans

dinoflagellates

euglenoidskinetoplastids(e.g., Trypanosoma)

?

Influenza virus A herpes virus

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lipid envelope (derived from host)

viral RNA

reverse transcriptase

viral coat (proteins)

viral protein

enveloped virus (HIV)

DNA

protein coat

sheath

base plate

tail fiber

complex virus

viral RNA

protein subunits of coat

helical virus

polyhedral virus

Lytic Pathway

Virus particles bind to wall of suitable host. Viral genetic material enters cell cytoplasm.

Viral DNA directs host machinery to produce viral proteins and viral DNA.

Viral protein molecules are assembled into coats; DNA is packaged inside.

Tail fibers and other parts are added to coats.

Lysis of host cell is induced; infectious particles escape.

Viral DNA usually becomes integrated into the bacterial chromosome.

Lysogenic Pathway

Prior to prokaryotic fission, the chromosome and integrated viral DNA are replicated.

After binary fission, each daughter cell will have recombinant DNA.

Viral DNA is excised from chromosome and cell enters lytic pathway.

Table 14.1Page 245

* Includes pneumonia, influenza, and whooping cough.

** Includes amoebic dysentery, cryptosporidiosis, and gastroenteritis.

500,000 1 millionBacteriaTetanus

1 million 200 millionVirusHepatitis B

1 million 200 millionVirusesMeasles

2.6 million 5.6 millionVirus (HIV)AIDS

2.5–2.7 million 110 millionSporozoansMalaria

3.1 million 9 millionBacteriaTuberculosis

3.1 million 1.8 billionBacteria, viruses, protozoans

Diarrhea**

4.7 million 1 billionBacteria, virusesAcute respiratory infection*

DiseaseEstimated Deaths

per YearEstimated New Cases per YearMain Agents

Table 14.1  The Eight Deadliest Infectious Diseases

HIV, agent of AIDS Agent of SARS

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