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Bacteria (Pages 470-477) All bacteria are prokaryotes (lacking a nucleus). Originally all bacteria were lumped together into one kingdom, Monera. Currently, bacteria are classified into two kingdoms: 1. Kingdom Archaebacteria archae means “ancient”, primitive/earliest bacteria. Lack peptidoglycan and have very different membrane lipids than the eubacteria. DNA is also more like eukaryotes than eubacteria. often called “extremophiles” as many live in harsh conditions such as sulfur vents and geysers. 2. Kingdom Eubacteria Have a carbohydrate called peptidoglycan that gives structure to their cell wall. Many different phyla as eubacteria can be heterotrophs (consumers, decomposers, parasites) or autotrophs (photo or chemosynthetic). Movement Most bacteria are unable to move Those that can move: o have a flagellum- which is a tail-like structure o glide/spiral forward Shapes Bacteria are named for the way they look. It consists of two parts: their arrangement and their shape. Arrangement Shape Strepto = chain Cocci = round Diplo = paired Bacilli = rod Staphylo = cluster Spirilla = spiral ___Streptococcus____ ____Bacilli___________ _____Spirilla___________ Cell Wall Eubacteria are further classified by their cell wall. A method called Gram staining, which consists of a violet and a red dye, is used to tell them apart. 1. Gram-positive: absorbs the violet dye and appears purple under a microscope. 2. Gram-negative: has an extra layer of lipids and carbohydrates, so absorbs the red dye and appears pink under a microscope. Mode of Nutrition Bacteria are either heterotrophs or autotrophs. Growth/ Reproduction: 1. Binary fission- the bacteria copies its DNA and separates into two identical daughter cells. This process is asexual and very similar to mitosis. 2. Conjugation- the bacteria forms a bridge with another bacteria and they transfer genetic material to one another. This helps create genetic diversity among bacteria. 3. Endospores- when conditions are unfavorable, bacteria can thicken their cell wall to form a tough protective coating that allows them to remain dormant until conditions are favorable again (boiling, freezing or dry conditions). Importance of Bacteria 1. Decomposers- break down nutrients in dead matter 2. Nitrogen fixers- Change nitrogen gas to ammonia or other nitrogen compounds. (into a form plants can use) 3. Human uses: Industry (examples= clean up oil spills, food/yogurt) Genetics (example= use plasmids in genetic engineering) Medicine (example= insulin) 4. Bacteria can be harmful pathogenic bacteria cause diseases such as strep throat, cavities, ulcers, food poisoning and Lyme disease. They can attack any of the 6 kingdoms.