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ISP 26.1

How Bacteria Are Classified Eubacteria or Archaea (Which Domain?) Mode of Nutrition Ability to produce Endospores Means of Mobility (Flagella?) Shape (cocci, bacilli, or spirilla) Gram Stain

Positive – thick peptidoglycan cell wall Negative – thin peptidoglycan cell wall

Prokaryotic Nutrition Bacteria differ in their need for, and tolerance of,

oxygen (O2). Obligate anaerobes are unable to grow in the

presence of O2; ex. botulism, gas gangrene, and tetanus

Facultative anaerobes are able to grow in either the presence or absence of gaseous O2.

Aerobic organisms (Obligate aerobes) - including animals and most prokaryotes) require a constant supply of O2 to carry out cellular respiration.

How Bacteria Obtain Energy Every type of nutrition, except for ingestion of

whole food, is found in bacteria. Autotrophs – manufacture their own organic

compoundsPhotoautotrophsChemoautotrophs

Heterotrophs – must obtain their energy by consuming organic substances produced by autotrophs.ParasitesSaprophytes (Saprobes)Decomposers

Pasteur’s experiments disproved the long held

belief in spontaneous generation

Reproduction in Prokaryotes

Sources of Genetic Variation In bacteria, genetic recombination can occur in

three ways.

1. Conjugation - occurs when a bacterium passes DNA to a second bacterium through a tube (sex pilus) that temporarily joins two cells; occurs only between bacteria in same or closely related species.

2. Transformation - involves bacteria taking up free pieces of DNA secreted by live bacteria or released by dead bacteria.

3. Transduction -bacteriophage transfer portions of bacterial DNA from one cell to another.

Bacterial Conjugation

Bacterial Conjugation Link

Transformation in Bacteria

Transformation in Bacteria Link

General Transduction

General Transduction Link

Endospore Formation Some bacteria form resistant endospores in

response to unfavorable environmental conditions.

Endospores survive in the harshest of environments: desert heat and dehydration, boiling temperatures, polar ice, and extreme ultraviolet radiation.

Heterotrophic Prokaryotes Some heterotrophs are symbiotic,

forming intimate, long-term relationships with members of other species; includes: Mutualistic Commensalistic parasitic relationships

The bacteria of genus Rhizobium invade the roots of legumes – resulting in the formation of nodule – The bacteria convert atmospheric nitrogen to an organic nitrogen that the plant can use

Heterotrophic Prokaryotes Commensalistic bacteria live in or

on organisms of other species and cause them no harm.

Parasitic bacteria are responsible for a wide variety of infectious plant, animal and human diseases.

The Bacteria Gram Stain & Shape

The Gram stain procedure (developed by Hans Christian Gram) differentiates bacteria. Gram-positive bacteria stain purple,

whereas Gram-negative bacteria stain pink.

This difference is dependent on the thick or thin (respectively) peptidoglycan cell wall.

The Bacteria Bacteria and archaea have three basic

shapes. spirillum - spiral-shaped. bacillus - elongated or rod-shaped bacteria Coccus - bacteria are spherical

Cocci and bacilli tend to form clusters and chains of a length typical of the particular species.

The Archaea Carl Woese - base sequence of their

rRNA differs from Bacteria

Other differences: Archaea do not have peptidoglycan in

their cell walls like the Bacteria Archaea biochemical more like Eukarya

than Bacteria Archaea now thought to be more

closely related to Eukarya than to Bacteria

The Archaea Types of Archaea

Methanogens live under anaerobic environments (e.g., marshes) where they produce methane.

Halophiles require high salt concentrations (e.g., Great Salt Lake).

Thermoacidophiles live under hot, acidic environments (e.g., geysers).

Kingdom Protista Catch all Kingdom - artificial & used more

for convience. Eukaryotic cells (Endosymbiotic Theory) Most are unicellular (some filamentous,

colonial or multicellular) Animal-like, plant-like or fungus-like Asexual reproduction the norm, but some

reproduce sexually.

Endosymbiotic theory

Kingdom Protista Complexity

Eukaryotic Autotrophic or Heterotrophic Highly varied life cycles (asexual & sexual

reproduction) Highly specified organelles Symbiotic relationships

(parasitismmutualism)

The Green Algae Green algae are believed to be closely

related to the first plants because both of these groups have a cell wall that contains cellulose, possess chlorophylls a & b store reserve food as starch inside of the

chloroplast.

Red Algae

Brown Algae

CO 22

Diatoms & Golden Brown Algae

Dinoflagellates

Red Tide

Euglenoids

Zooflagellates

Ameboids

Ciliates

Sporozoans(Malaria)

Slime Molds

Slime Molds

Figure 22.19Water Molds

Kingdom Fungi Multicellular Eukaryotes Heterotrophic by absorption Saprotrophic decomposers -breaking down

wastes or remains of plants & animals Parasitic, mutualistic Others form an association with a green alga

or cyanobacterium to form a lichen Energy reserve Glycogen (unlike plants)

Terms to know:

Hyphae (singular hypha)

Mycelium (singular mycelia)

Chitin

Figure 23.3

Pg 410

Yeasts are unicellular & reproduce asexually by mitosis or budding

Yeasts produce ATP through fermentation - ethanol & CO2 are waste products Yeast fermentation is important in the production of wine, beer & breads

Athletes Foot

Ringworm

Club Fungi – MushroomsFairy Ring

Figure 23.9bClub Fungus – Shelf Fungus

Figure 23.9d

Symbiotic Relationships of Fungi

Lichens are a symbiotic association between fungus and cyanobacterium or green alga

Three types of lichens are recognized. Compact crustose lichens are often seen on

bare rocks or tree bark. Leaflike foliose lichens Shrublike fruticose lichens

Symbiotic Relationships of Fungi

Mycorrhizae are mutualistic relationships between soil fungi and roots of most plants

It helps the roots absorb more minerals; in turn, the plant passes on carbohydrates to the fungus