Kingdom Archaebacteria Section 9.3

Archaebacteria Oldest living organisms ~3.5 billion years Prokaryotes Archae – means “primitive” or “old” Prokaryotes Unicellular Heterotrophs Live in extreme habitats similar to the Earth when it was first formed. Do not require oxygen (anaerobic) Not recognized as different from other bacteria until the 1970s

Extremophiles

3 Types Methanogens Extreme thermophiles Extreme halophiles produce methane gas Extreme thermophiles up to 110oC Extreme halophiles salt-loving

Kingdom Eubacteria “True bacteria”

Classification: 3 basic shapes Coccus (pl: cocci) Spherical Bacillus (pl: bacilli) Rod-shaped Spirillum (pl: spirilla) Spiral

Characteristics Prokaryotes Unicellular, but cells may be found in clusters, pairs or chains Autotrophs or heterotrophs Adapted to many different environments Arctic Deep ocean Inside and outside of animals’ bodies

Examples Staphylococcus aureus Escherichia coli Streptococcus mutans Streptococcus pneumoniae

Similarities between the 2 kingdoms Archaebacteria & Eubacteria were once one kingdom: Monera

Respiration Respiration is necessary to provide heterotrophic organisms with energy Eubacteria may be obligate aerobes, obligate anaerobes or facultative anaerobes Aerobic = needs oxygen Anaerobic = does not need oxygen Obligate = has to do, or has to have So: Obligate aerobes: have to have oxygen for respiration Obligate anaerobes: do not use oxygen for respiration Facultative anaerobes: prefer to do respiration with oxygen, but can also live without it

Eubacteria Nutrition Most: heterotrophs Some: parasites (disease causing bacteria) Some: decomposers (saphrophytes) Some: autotrophs Photosynthesis Chemosynthesis (synthesize carbs using chemical reactions for energy)

Reproduction (both kingdoms) Asexual Resulting cells are identical Binary fission Bacterium makes a copy of its DNA Cell gets bigger Wall is formed between the 2 halves of the cell Cell splits into 2

More reproduction… Sexual reproduction Involves 2 separate bacteria cells Donor makes contact with recipient and gives pieces of DNA (plasmids) Called conjugation Not common Resulting cells are not identical (contributes to genetic variation)

Endospores Adaptation to surviving in unfavourable conditions Genetic material surrounded by thick, resistant cell walls Dormant (resting) Can stay dormant until favourable conditions return

Beneficial bacteria Some produce useful chemicals Ethyl alcohol, acetic acid, butyl alcohol, acetones Some produce food for humans through fermentation Cheese, yoghurt, sauerkraut Some produce antibiotics to fight other types of harmful bacteria Decomposers recycle nutrients Some bacteria breakdown harmful chemicals

Disease Many are pathogens Cause harm in different ways: Destroy cells and/or tissues Produce toxins Interfere with normal functions of cells and tissues Bacteria can be transmitted from person to person

Homework Practice questions, page 344 #1-7