Post on 28-May-2019
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Archaebacteria: The Extremists
• 3 types
• Type 1: Lives in oxygen free environments and produce methane gas
• Type 2: Lives in high salt environments not survivable by other organisms.
• Type 3: Live in acidic waters and sulfur springs, as well as thermal vents near the ocean floor.
Eubacteria: The Heterotrophs
• Live almost everywhere organic molecules can be found (except where the archaebacteria live)
• Very diverse
• Can be found as autotrophs, heterotrophs
Heterotrophic Bacteria
• Some adapted to engulfing organic molecules.
• Others are parasites that obtain nutrients from living organisms.
• Some, called saprophytes, break down dead organisms and release organic matter back into the environment.
Photosynthetic Autotrophs
• Live in places with lots of sunlight
• Contain chlorophyll
• Most are blue green in color: Called cyanobacteria
• Credited for oxygenating our atmosphere
Chemosynthetic Autotrophs
• Make their own food but instead use inorganic materials containing sulfur and nitrogen.
• Responsible for “fixing” the nitrogen in soil.
• Many live on the roots of plants in a symbiotic relationship.
Bacterial Parts
• Capsule: Some bacteria have a gelatinous capsule around the cell wall. Bacteria with capsules are more likely to cause disease.
• Cell Wall: Gives shape, prevents osmosis from bursting the cell.
• Chromosome: Single DNA molecule arranged in a circle. Not in a nucleus!!!!
• Flagellum: Used for locomotion.
• Plasmid: Few genes in small circular chromosome.
• Pili: Hairlike structure that allows bacteria to stick to other surfaces.
Identifying Bacteria
• Bacteria can be identified by gram staining of the cell wall.
• Gram positive bacteria turn purple, gram negative bacteria turn pink.
Bacterial Shapes
• Cocci: Spheres
• Bacilli: Rods
• Spirilla: Spirals
• Staphylo: Grapes
• Strepto: Chains
• Diplo: Pairs
Bacterial Reproduction
• Binary Fission (Asexual): Copies chromosomes and divide creating an exact copy.
• Conjugation(Sexual): One bacterium uses its pili to transfer genetic information to another bacterium. This results in a bacterium with new genetic info.