Bacteria & Protists Conjugation Binary fission

Bacteria and early life The __________ life-form was bacterial, ~ 3.8 bya Some were probably __________________ “chemo-” = extract energy from _______ compounds “auto-” = synthesize sugars from ____ Others got energy by _________ respiration of sugars __ was rare in early Precambrian ~3.0 bya, _____________ bacteria appear Very successful, worldwide Released __ as a byproduct of ____ Changed Earth’s atmosphere Bacteria > early life

Photosynthetic membranes of individual bacterium Living mats of bacteria Stromatolites: fossilized mats of photosynthetic bacteria

The major branches of life Kingdoms: ______ (external digestion) _________ (photosynthetic) ________ (ingest food) Multicellular Unicellular Domains: Prokaryotic cell design Eukaryotic 1st cellular organism

Protists: single-celled organisms Taxonomy of protists changed as knowledge improved 1700s – 1800s: K:Plantae, K:Animalia New knowledge: Fungi are not photosynthetic Bacterial cells differ greatly from plant & animal cells Early 1900s: K:_______, K:Fungi, K:Plantae, K:Animalia New knowledge: Some single-celled creatures are equally plant & animal Late 1900s: K:Monera, K:Fungi, K:Plantae, K:Animalia, K: ______ New knowledge: Archaebacteria are much different than all other life-forms Differences between protist taxa are greater than plant vs. animal ~ 2000: 3 _______: Bacteria, Archaea, Eukaryota Many (20?) Protist Kingdoms within Eukaryota Protists

Only superficially similar to ______ bacteria Archaebacteria Only superficially similar to ______ bacteria Unique cell membrane & cell wall Rare today ____________: live in extreme environments Geothermal pools, salt lakes, deep sea ____ Bacteria > Archaebacteria

Eubacteria (_________ Bacteria) General features: Cell wall (________ to plants’) Pili: ‘hairs,’ stick to _________ Sex ____ for conjugation Exchange of ____ Endospore (in many species) Thick wall Resists _________, heat, chemicals Can remain dormant for _________ Must _________ at 250oF to destroy Bacteria > Eubacteria

Most abundant life-form today Taxonomy based on: 1) ________ of cell wall Gram positive (stain ________): Anthrax Thick wall made of ____________acid Gram negative (stain ________): Thin wall covered by outer membrane 2) shape: 1) Cocci, ________ e.g., Gonococcus 2) Bacilli, r________ e.g., Anthrax 3) Spirochete, _____ e.g., Syphilis Bacteria > Eubacteria

~ 1/1,000 as much DNA as eukaryotic cells Prokaryotic DNA ~ 1/1,000 as much DNA as eukaryotic cells Occurs as a single ________ chromosome Contains all _________ genes Can also have small circular DNA _______ DNA Plasmid Conjugation tube (cell 1) (cell 2) Contains genes for _______circumstances e.g., antibiotic resistance Can be exchanged between cells By conjugation Allows “_____” of useful traits Scientists use plasmids to insert and clone _______ Bacteria > Eubacteria > genetics

Prokaryotic protein synthesis Transcription and translation occur ________ Prokaryotes have no nuclear membrane ________ translate mRNA as it is transcribed Simple, more direct than eukaryotes DNA Ribosome Messenger RNA Protein transcription translation Bacteria > Eubacteria > genetics

Ecological roles of modern bacteria Many have _____ byproducts that cause disease: E.g, plague, TB, cholera, anthrax Others are ________ recyclers: 1) Decomposers: Break down ________wastes 2) Fixers: Make ______ available to plants & animals E.g., nitrogen-________ bacteria Live in root ______ of legume plants Convert N gas into _____ N compounds A type of ________ Bacteria provide N, plants provide _______ Bacteria > Eubacteria > ecology

Single-celled Eukaryotes Paramecium Protist Kingdoms: Single-celled Eukaryotes Appeared ~__ bya Evolved from __________ Through endosymbiosis E.g., photosynthetic bacterium became _________ of eukayrotic cell Can be animal-like, plant-like, or fungus-like Formerly included in those kingdoms Occur in all _______ environments Including _______ other eukaryotes Protists

1) Animal-like protists Unifying feature: _____ food, digest it internally a. Flagellates Move by flagella Trypanisoma Giardia Protists > Flagellates

b. Ciliates Move by cilia Protists > Ciliates

Move by pseudopodia – “________” Edge of cell spreads like “The Blob” c. Amoebas Move by pseudopodia – “________” Edge of cell spreads like “The Blob” Pseudopodia Protists > Amoebas

2) Plant-like protists: Unicellular algae Most are photosynthetic a. Green algae -__________ -2 flagella -Cell wall contains _______ Protists > unicellular algae > green algae

Cell wall contains ____ (glass) b. Diatoms Cell wall contains ____ (glass) Very abundant in the sea Form ‘diatomaceous earth’ and _____ foam Protists > unicellular algae > diatoms

3) Fungus-like protists: e.g., slime molds _________ digestion, no ingestion Eat decaying matter and bacteria Can have uni- and multicellular ______ Lack of ____ initiates stage transition Multicellular slime mold “slug” Protists > fungus-like

1) Food becomes depleted Life cycle of slime molds: 3) Fruiting bodies bear ______ 4) Amoeboid generation emerges from spores, eats food _______ body develops Slime mold cells cover food 2) Food source found, 1) Food becomes depleted Multi-cell _____ forms, moves Protists > fungus-like