Chapter 23: Bacteria Archaea and Bacteria

Kingdom Archaebacteria – the most primitive organisms (archae = ancient) live in harsh conditions including -acidic hot springs -very salty water -environments with no oxygen -near undersea volcanic vents - different from other bacteria -cell wall composition (pseudomurien) -Cell membrane -rRNA

Phyla 1: Methanogens : - obligate anaerobes (oxygen kills them) - metabolizes hydrogen gas and CO 2 to methane gas - live in the bottom of swamps, sewage, and inside the digestive tracks of many animals Helps -grazing animals process cellulose -termites process wood -in industry to treat sewage, purify water.

Phyla 2: Thermoacidiphiles - can live in extremely hot and acidic water or deep in the ocean near hydrothermal vents in the ocean floor -Ex: hot springs of Yellowstone Natl Park - chemotrophs = process sulfur compounds to produce energy

Phyla 3: Halophiles: - live in extremely salty (saline) environments, ex: Dead Sea - use the salt to generate ATP.

Phyla 4: Psychrophiles -live in temperatures below 15C -Found mostly in the Arctic and Antarctic oceans sea ice.

Kingdom Eubacteria (Eu = true) “Germs”

1)Composition of the cell wall – identified with Gram staining technique Gram positive – stains purple – thick outer layer of peptidoglycan Gram negative – stains pink/red – lipid layer covering thin layer of peptidoglycan Peptidoglycan – a protein-carbohydrate compound Characteristics used for classifying:

3)Type of metabolism obligate aerobe – must have oxygen; dies without it obligate anaerobe – dies if exposed to oxygen; processes ATP by fermentation facultative anaerobe – uses oxygen when it can but doesn’t need it 4)Shape of bacterial cells roundcoccus (cocci) rod shapedbacillus (bacilli) spiral shapedspirillus 2. Method of getting energy: autotrophic (chemotroph, phototroph), heterotrophic

5)How cells grow (prefixes) a)staphylo – clumps b)strepto - chains c)diplo - pairs 6)Motility – movement a)flagellated – move with flagellum or flagella b)slime layer allows gliding c)spirochete - cork-screw rotation

A)Proteobacteria may have symbiotic lifestyle ex. Nitrogen fixing bacteria inside legumes (ex: beans) In human and animal intestines, help break down foods (enteric bacteria) Some in soil or fresh water and process iron and other minerals as an energy source (chemotrophs)

B) Gram positive - thick outer layer of peptidoglycan (stains purple) - may be beneficial or cause disease - may be used to make yogurt, pickles, and buttermilk - or to make medicines using biotechnology Ex. Strep throat ; staph infections; tuberculosis

C) Cyanobacteria Gram-negative contain chlorophyll (but not chloroplasts), perform a plant-like photosynthesis releasing oxygen as a by- product Ex. Filamentous bacteria (grow in stagnant water)

D) Spirochetes - gram negative - spiral shaped E) Chlamydia (no peptidoglycan) - gram negative - round shape - are parasites to animal cells

Reproduction – 2 types Asexual - most common Binary fission – divides into two new cells Sexual – exchanges genetic info giving variation a)conjugation - two bacterial cells connect with a hair-like “pili” - info is passed through the tube b)transformation – living bacteria absorbs dead related bacterial DNA and incorporates it into it’s own genome c)transduction – a virus transfers DNA

Endospores - special dehydrated cells formed by some bacteria to survive bad living conditions - ex: high temperatures - when conditions improve cell is revived

Bacteria and Disease Toxins – poisons produced by some bacteria 1) endotoxin - created inside the bacterial cell - released as the cell dies - usually Gram neg. 2) exotoxin - secreted by living bacterial cell into surrounding environment (host) - usually Gram-positive

Pathogens – bacteria that cause disease Antibiotics - chemicals that kill bacteria by interfering with cellular functions such as protein or cell wall synthesis - Gram positive bacteria that cause disease need different antibiotics than Gram negative bacteria Antibiotic Resistance in Bacteria most of the population dies, some survive Survivors reproduce and are no longer affected by antibiotic Occurs when antibiotics are overused or used improperly