Diversity of Prokaryotes Environmental Conditions
-Temperature
-Grows best below 20 C psychrophiles -Grows best between 20-50 C mesophiles -Grows best above 50 C thermophiles
-pH(acidic and basic environment) -Grows well at pH of 1 to 2 (acidic) acidophiles i.e H. Pylorg -Grows best near neutral pH Neutrophile pH around 7 , found in water and milk -Grows well at pH as high as 9 (basic) Alkaliphile (some structures that can survive disinfectants) -Water -Most cells require a minimum moisture content -Some bacteria can make spores (can survive dry environment) : cells that survive in the near absence of water
Salt -Most cells require a moderate level of salt -Some can exist in very high salt concentrations, most preferably Halophiles
Oxygen Availability -Require oxygen for growth aerobic - Require lack of oxygen for growth anaerobic
Nutrient Availability -Most microorganisms require organic and inorganic nutrients to grow and survive -Cyanobacteria grow in the absence of key nutrients, i.e can convert CO2 from air into organic cellular molecules.
The Evolution of Life on Earth
-3.8 beginning of life
-every cell formed during evolution gives advantage to viruses
Origin of life universal ancestor (Archae (extreme environments, in the human body, no nucleus), Bacteria (no nucleus), Eukarya (animals, plants, made out of larger cells with a nucleus)) - THE TREE OF LIFE
-Archae is closely related to Eukarya than both to bacteria
Archae -Morphologically, the two kingdoms of Prokaryotes appear similar. However, they have major biochemical differences such as their cell wall.
-Most archae live in extreme environments -thermoadaciles -methanogens - Lecture 9, September 26th, 2014
-Both archae and bacteria are both prokaryotes and therefore, no nucleus
Diversity of Microbes
-Fungi(Yeast): -eukaryotic unicellular organism - most commonly used in the food industry -under aerobic conditions used as a baker’s yeast -under anaerobic
