Bacteria Notes PDF

Bacteria Notes There are more bacteria on this planet then everything else combined! There are more individual bacterial cells in your mouth right now than there are mammals on the entire planet. All bacteria are single-celled organisms that are prokaryotes. Prokaryotic means that they do NOT have...

Bacteria Notes There are more bacteria on this planet then everything else combined! There are more individual bacterial cells in your mouth right now than there are mammals on the entire planet. All bacteria are single-celled organisms that are prokaryotes. Prokaryotic means that they do NOT have a nucleus and they do NOT have membrane bound organelles (mitochondria, chloroplasts, etc.). Bacteria are single-celled organisms that fall into two kingdoms. Kingdom Archaebacteria – “ancient bacteria”; these are thought to resemble the first life forms on Earth from a time when the Earth’s environment was very different from today. Most of these bacteria are thought to like extreme environments and are classified by where they can be found: Methanogens – live in areas that are low in oxygen. They produce methane (aka swamp gas). They are also found in the intestines of cows. Thermoacidophiles – These like really high temperatures (60 – 250 C) and areas of high acidity (pH 2 – 4). They are found in hot springs like Yellowstone National Park. Chemosynthesizers – These use inorganic compounds and convert them to energy. The are found near deep ocean vents. They convert H 2S to energy. Extreme Halophiles – These live in extremely salty conditions, where other things could not exist. They can grow in areas up to 10 times saltier than normal sea water. (Dead Sea, Great Salt Lake) Kingdom Eubacteria – these bacteria are different in 3 ways: 1) their cell walls contain peptidoglycan 2) their plasma membranes contain different lipids (fats) and 3) their DNA is different Eubacteria are classified by several methods: 1) Shape – rod-shaped (bacillus); circular (coccus); spiral-shaped (spirilla); and comma (vibrio) 2) Cell Wall Composition – determined by gram staining procedure. Gram Positive – stain purple Gram Negative – stain red 3) Motility – how and if they move (flagella – a whiplike tail) 4) Appearance of the Colony – groups of bacteria form colonies. They can form a variety of textures, shapes, and colors. 5) Respiration – Aerobic Anaerobic  Facultative Anaerobes Obligate Aerobes and Obligate Anaerobes 6) Metabolism – source of energy autotrophs – make their own food (photosynthetic) heterotrophs – consume other organisms chemotrophs – consume inorganic compounds Bacterial Reproduction – occurs it many different ways 1. Binary Fission – asexual; produces identical cells. The chromosome replicates and the cell divides. Most bacteria can double every 20 minutes. 2. Conjugation – the to cell exchange of genetic material. This is a type of sexual reproduction. Two bacteria will connect using structures called pilli and genetic material is exchanged. 2. Transformation - This occurs when living bacteria pick up DNA from dead bacterial cells. 3. Transduction – This is when a virus is used to transport bacterial DNA from one cell to another cell. 4. Endospores – Some species develop these when conditions become unfavorable for the bacteria. Later, when conditions improve, the spore dissolves and the bacterial cell reactivates. Treating Bacterial Infections: Typically, bacterial infections are treated with _antibiotics_________. The word antibiotic literally means “against living things”. These drugs usually work by disrupting the _cell membrane___ of the bacterial cell. They can also inhibit normal protein synthesis in bacterial cells. Recently there have become cases of _antibiotic_ __resistance___ in which bacterial cells have acquired an immunity to the drugs that previously killed them. This has occurred as a result of the improper use of antibiotics. Some bacterial infections can be _prevented__ through the use of vaccines, in a way that is similar to viral vaccines. (Examples are Tetanus, Diptheria, and Whooping Cough) The following are list of bacterial infections which have or can affected humans: E. coli Strep Throat Salmonella Bacterial Meningitis TB (Tuberculosis) Gonorrhea Bacterial Pneumonia Diptheria Syphillis MRSA Whooping Cough Chlamydia Bubonic Plague