Unit 5 Classification Microorganisms Kingdom Archaebacteria Kingdom Eubacteria

Unit 5: Classification / Microorganisms Kingdom Archaebacteria, & Kingdom Eubacteria

Kingdom Archaebacteria: Ancient Bacteria a. k. a. Domain Archaea n Prokaryotes n Live in extreme conditions n NO PEPTIDOGLYCAN thick outer covering of archaebacteria n

Kingdom Archaebacteria: Ancient Bacteria n 1) 2) 3) 3 types: Methanogens – produce methane gas Halophiles – “salt-loving” Thermophiles – means “heat-loving”

Kingdom Eubacteria: Pathogenic Bacteria A. k. a. Domain Bacteria n Prokaryotes n Live almost anywhere (very diverse) n Cell walls w/ peptidoglycan n

Kingdom Eubacteria: Pathogenic Bacteria n Examples: – Streptococcus – Staphylococcus aureus – Bacillus pneumonae – Clostridium botulinum

Prokaryote Classification – 3 Main Ways n 1) Prokaryotes are classified based on SHAPE, CELL WALLS, and how they obtain/release ENERGY. Shapes – Cocci: round (letter C) – Bacilli: rod-shaped (letter A) – Spirilla: spiral-shaped (letter B)

Figure 27. 3 The most common shapes of prokaryotes

Prokaryote Classification 2) Cell Walls – How much peptidoglycan?

Gram staining n n n Adds dye to bacteria the way it stains is an indicator of the type of bacterium (its structure) Gram positive = stains PURPLE – has simple, thick cell wall made of polysaccharides Gram negative: stains PINK – has a protective outer cell membrane; less peptidoglycan in cell walls; structurally more complex (contain lipopolysaccharides that are often toxic to host) *negatives are more resistant to antibiotics

3) Energy Obtained (4 ways) 1) 2) 3) 4) Photoautotroph – uses light energy to produce own food Chemoautotroph – uses inorganic molecules (chemicals) to produce own food Photoheterotroph – needs sunlight to obtain food; cannot produce their own food Chemoheterotroph – uses products of chemical reactions to obtain food; cannot produce their own food.

3) Energy Releasing (3 Ways) n Prokaryotes can either be… 1) Obligate Aerobes – requires oxygen 2) Obligate Anaerobes – requires NO oxygen (Ex: Clostridium botulinum = botulism & BOTOX) 3) Facultative Anaerobes – can function in the presence of oxygen

Movement n Have Flagella n Lash/Spiral forward n Glide using secretions n Not Move sessile

Bacterial Reproduction n Grow and divide VERY rapidly Exponential growth (J curve) n Asexually by Binary Fission (Budding) a method of reproduction in which a prokaryote replicates its DNA and divides in half producing 2 identical “daughter cells”

Bacterial Reproduction n Sexually by Conjugation - the transferring of genetic information from one prokaryote to another, with pilli

Bacterial Reproduction n In unfavorable condition, bacteria can form Endospores - the process of producing a thick internal wall that allows the prokaryote to remain dormant for long periods of time while conditions are unfavorable for reproduction

BACTERIA CAN BE GOOD & BAD!!!

Bacteria in Nature n Bacteria are vital to maintaining the living world: – Some are producers that capture energy by photosynthesis – Live in our digestive tracts, and break down the food we need to survive – Live on our skin and eat dead skin cells & other harmful bacteria trying to invade us. n As decomposers, bacteria help the ecosystem recycle nutrients – The bacteria breaks down the dead matter into simpler substances n As recyclers, bacterial also perform critical steps in sewage treatment – Bacteria break down complex compounds in the sewage into simpler ones

Bacteria as Nitrogen Fixers n Plants and animals depend on bacteria for nitrogen – Although the Earth’s atmosphere is approximately 80% nitrogen gas (N 2), plants cannot use that nitrogen directly – The process of converting N 2 to a form of nitrogen that plants can use (NH 3) is called nitrogen fixation » Certain bacteria are the only organisms that can fix nitrogen in this way

Nitrogen Fixation n Many plants have a symbiotic relationship with nitrogen fixing bacteria – Soybeans and other legumes host the bacterium Rhizobium » Rhizobium grows in nodules that form on the roots of the plant » The plant provides a source of nutrients for Rhizobium, which converts nitrogen in the air into ammonia, which helps the plant

Bacteria and Disease n Bacteria are everywhere in nature, but only a few cause disease – Bacteria that cause disease are called pathogens n Bacteria can cause disease in one of two ways: – By damaging the tissues of infected organisms as they break them down for food – By releasing toxins that harm the body of the organism

Common Diseases Caused by Bacteria DISEASE PATHOGEN Tooth decay Streptococcus mutans Regular dental hygene Lyme disease Borrelia burgdorferi Protection from tick bites Tetanus Clostridium tetani Tuberculosis Mycobacterium tuberculosis PREVENTION Current tetanus vaccination Vaccination Salmonella enteritidis Proper handling of food Pneumonia Streptococcus pneumoniae Maintaining good health Cholera Vibrio cholerae Clean water supplies

Antibiotics vs. Antiseptics n Antibiotics – compounds that block the growth & reproduction of bacteria internally – introduced INTO body as injection or – ONTO site of infection as surface medication » EX: Penicillin

n Antiseptics – Kill bacteria on OUTSIDE of body or on membranes that line areas leading to inside (ex. Mouth) Ex. n Alcohol Listerine Iodine Hydrogen Peroxide Neosporin Antibacterial soap Disinfectants – act as surface antiseptics for non-living surfaces before bacteria even get to body Ex. Clorox Lysol Ammonia

Human Uses of Bacteria n Bacteria are used in the production of a variety of food: – Cheese, yogurt, wine, buttermilk, etc. n Bacteria are used in industry: – Cleaning up oil spills, removal of wastes from water, synthesis of drugs

Controlling Bacteria n Sterilization: destroys bacteria by subjecting them either to great heat or to chemical action n Refrigeration: causes bacteria to grow slowly n Preservatives: canning prevents bacteria from spoiling shelf foods n Chemical Treatment: chemicals (such as salts) can prevent the growth of bacteria in food