Kingdom Bacteria and Archae

• Binary fission is a form of asexual reproduction in which an organism divides into two, each part carrying one copy of genetic material
• Bacteria can be found in almost every environment on Earth, from arctic ice to volcanic vents
• 1 teaspoon of soil has over 1 billion bacteria in it
• 1 cm^2 of your skin has 100,000 bacteria on it
• In the human body, bacterial cells outnumber human cells by 10 to 1
• All bacteria are single-celled
• All bacteria are prokaryotic (lack nucleus and membrane-bound organelles)
• All bacteria reproduce asexually by binary fission
• All bacteria contain DNA made of a single chromosome
• DNA is not enclosed in a nucleus for (Eu)bacteria and Archaea(bacteria)
• Flagellum: a whip-like tail for movement, not always present
• Cilia: tiny hair-like projections use coordinated rhythm to move
• Plasmid: a loop of DNA which is exchanged during conjugation
• Cytoplasm contains ribosomes for protein synthesis
• Capsule reduces water loss, resists high temperatures and protects against antibiotics and viruses
• Some bacteria take nitrogen directly from the air to make proteins
• These bacteria usually live in nodules on roots of legumes
• Bacteria are key in the breakdown of dead organisms and the cycling of carbon dioxide back into the atmosphere
• Human large intestine produces Vitamin K and B12
• Bacterial cells can be in a variety of arrangements
• Gram-positive bacteria have a thick cell wall and are mostly harmless e.g. Streptococcus
• Gram-negative bacteria have a thin cell wall and many are pathogenic e.g. E. coli, Salmonella
• Some bacteria and archaea have the ability to make their own food (autotrophs), while others require the taking in of food from an external source (heterotrophs)
• Photosynthetic (Photoautotrophs) synthesize their own food with the help of light energy
• Chemosynthetic (Chemoautotrophs) obtain energy from organic or inorganic compounds
• Aerobe requires oxygen e.g. genus - Corynebacteria on the skin
• Obligate Aerobe die when exposed to oxygen e.g. genus - Clostridium in the large intestine
• Facultative Aerobe uses oxygen when present, but can grow without it e.g. genus - Escherichia in the large intestine
• Reproduction in prokaryotes is mostly asexual through binary fission
• During genetic recombination, DNA carrying new genes is transferred to a prokaryotic cell
• Bacterial Conjugation is a transfer of genetic material from one prokaryotic cell to another
• Some bacteria can form endospores when conditions deteriorate to protect and store genetic material
• (Eu)bacteria form endospores and are resistant to high temperatures, drying out, radiation, and toxic chemicals
• Most (Eu)bacteria tend to live in moderate environments = Mesophiles
• Some (Eu)bacteria live in more extreme environments and are responsible for causing diseases in animals, plants, viruses, etc
• Archaea(bacteria) thrive in extreme environments = Extremophiles
• Archaea(bacteria) can survive in extremely acid or alkaline environments, at the edge of active volcanoes, in methane-saturated swamps, and black organic mud devoid of oxygen
• Methanogens live in anaerobic environments and produce methane gas
• Thermophiles live in extreme heat environments
• Halophiles live in saline environments