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Add to table of contents: Bacteria data sheet Bacteria Pg.78 Pg.79 Identifying Prokaryotes Factors needed to identify a prokaryote: 1) Shape a) Bacilli: rod-shaped Identifying Prokaryotes b) Cocci: spherical (bead-like) Identifying Prokaryotes c) Spirilla: spiral or cork-screw shaped Identifying Prokaryotes 2) Movement: some move, others do not. Flagella: whip-like structures used for movement. Some move like snakes, spiral, glide. Growth and Reproduction Bacteria may grow and divide in 3 ways: 1) Binary Fission: copies DNA and divides in half; no exchange or recombination of DNA (asexual). Growth and Reproduction 2) Conjugation: bridge between 2 cells; genes are exchanged between the 2 bacteria. Growth and Reproduction 3) Spore Formation: in harsh conditions, bacteria form spores for protection. In favorable conditions bacteria can reproduce very quickly. Some bacteria can reproduce every 20 minutes, producing an enormous number of bacteria quickly. If bacteria always reproduced this fast, they would cover the surface of the earth within a few weeks. Look at the data below and graph. Time (Minutes) 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 Bacteria Cells 2 4 8 16 32 64 128 256 512 1,024 2,048 4,096 8,192 16,384 32,768 Importance of Bacteria Bacteria are essential to all forms of life A) Decomposers: help ecosystem recycle nutrients and break down compounds in sewage treatments B) Nitrogen Fixers: convert N2 gas into form plants can use and recycles it in atmosphere C) Human Uses: food, beverages, industrial, purification, etc. E. coli: help make vitamins in intestines Important Bacterial Diseases Streptococci Infections Streptococci (strep) are bacteria that are commonly found harmlessly living in the human respiratory, gut and genitourinary systems. Several species are capable of causing disease in humans, including skin diseases. Impetigo Cellulitis Necrotising faciitis E. Coli Infections Most E. coli are harmless and actually are an important part of a healthy human intestinal tract. However, some E. coli are pathogenic, meaning they can cause illness, either diarrhea or illness outside of the intestinal tract. Meningitis Meningitis is a disease caused by the inflammation of the protective membranes covering the brain and spinal cord known as the meninges. The inflammation is usually caused by an infection of the fluid surrounding the brain and spinal cord.