Microbes Microbes Bacteria and Protists

Three Domain Organizational Scheme Six Kingdoms PROKARYA

Bacteria Archaea

Sizes of Prokaryotic Cells Non-living entities made of genetic material + protective coat

Characteristics of Bacteria and Archaea ProkaryoticProkaryotic Single CelledSingle Celled Many nutritional modesMany nutritional modes –Heterotrophic –Autotrophic: photosynthetic or chemosynthetic Reproduce by binary fissionReproduce by binary fission Gene transfer with conjugationGene transfer with conjugation Cell wallCell wall

Binary Fission

Conjugation: Transfer of DNA From Donor to Recipient Sex Pilus Donor Recipient

Archaea Unique lipid membranes, cell walls, and ribosomal RNAUnique lipid membranes, cell walls, and ribosomal RNA MethanogensMethanogens –Convert CO 2 to methane –Found in swamps, hot springs, vent communities, cow stomachs Halophiles - survive in a concentrated salt environmentHalophiles - survive in a concentrated salt environment Thermoacidophiles - thrive in a hot, acidic environmentThermoacidophiles - thrive in a hot, acidic environment

Prokaryotic Metabolism 1.Photosynthetic Bacteria cyanobacteria—use H 2 O, release O 2 sulfur bacteria-- use H 2 S, release sulfur 2.Chemosynthetic Both bacteria and archaea use chemical energy from ammonia, nitrate or sulfur

Prokaryotic Metabolism 3. Heterotrophic—gain nutrients from other organisms  pathogenic = disease -causing  non-pathogenic  decomposers– live on dead organic matter  nitrogen-fixing bacteria convert nitrogen gas into compounds plants can use convert nitrogen gas into compounds plants can use

Flesh-eating Bacteria

Adaptations to Severe Conditions Endospore formation protection against desiccation and temperature extremes Anaerobic metabolism can survive in the absence of oxygen

Applying Your Knowledge Which type of metabolism is used by A.Flesh-eating bacteria? B.Bacteria that use light energy to produce glucose? C.Bacteria that harness the chemical energy from sulfur to power their reactions? 1.Photosynthetic 2.Chemosynthetic 3.Heterotrophic

Characteristics of Protista EukaryoticEukaryotic Usually Single CelledUsually Single Celled Live in moist environmentsLive in moist environments Many nutritional modesMany nutritional modes –Heterotrophic –Autotrophic –Combination Sexual and asexual reproductionSexual and asexual reproduction

Three Groups of Protists Plant-like: Algae Fungus-Like: Water Molds, Slime Molds Animal-Like: Protozoa

Protist Reproduction Asexual Asexual reproduction occurs by mitosis. Sexual Sexual reproduction involves the exchange of genetic material across a cytoplasmic bridge.

Algae Photosynthetic Using Chloroplasts 1. Single-celled Algae Euglenoids have a single flagellum Dinoflagellates move with two whiplike flagella. Diatoms have silica shells.

A “Bloom” of Dinoflagellates Causes Red Tide

Algae Photosynthetic Using Chloroplasts 2. Multicellular Algae

Fungus-Like Protists Heterotrophic by Absorption Water mold Slime mold

Single, amoeba- like cells emerge from spores, crawl, and feed. When food is scarce, cells aggregate into slug- like mass called a pseudoplasmodium. Pseudoplasmodium migrates toward light, forms fruiting bodies that produce spores. fruiting bodies spores nucleus The Life Cycle of a Cellular Slime Mold

Protozoa Heterotrophic by IngestionHeterotrophic by Ingestion Distinguished by LocomotionDistinguished by Locomotion Sporozoans have no means of locomotion Sarcodines move with pseudopodia

Protozoa Heterotrophic by IngestionHeterotrophic by Ingestion Distinguished by LocomotionDistinguished by Locomotion Zooflagellates use flagella for movement. Ciliates use cilia for movement.

Applying Your Knowledge Which mode of nutrition is used by A.Cellular Slime Molds? B.Sarcodines like Amoebas? C.Multicellular Algae? D.Zooflagellates like Giardia? 1.Heterotrophic by Ingestion 2.Photosynthetic 3.Heterotrophic by Absorption