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BACTERIA. Chapter 20.2. Agenda. November 10 – Day 4 Bacteria Notes Bacterial Disease Poster Project. This is a pore in human skin and the yellow spheres are bacteria. Clean skin has about 20 million bacteria per square inch. Evolution/Classification. Prokaryotes
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BACTERIA Chapter 20.2
Agenda • November 10 – Day 4 • Bacteria Notes • Bacterial Disease Poster Project
This is a pore in human skin and the yellow spheres are bacteria
Evolution/Classification • Prokaryotes • The oldest fossils known, nearly 3.5 billion years old, are fossils of bacteria-like organisms. • Evolution has yielded many species adapted to survive where no other organisms can. • Grouped based on: • Structure, physiology, molecular Composition, reaction to specific types of stain (Gram Positive/Gram Negative). • Eubacteria= Germs/bacteria • Archaebacteria
Kingdom Archaebacteria • First discovered in extreme environments • Methanogens: Harvest energy by converting H2 and CO2 into methane gas • Anaerobic, live in intestinal tracts • Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea. • Thermoacidophiles: Live in acid environments and high temps. • Hot Springs, volcanic vents
Depending on the species, bacteria can be aerobic which means they require oxygen to live or anaerobic which means oxygen is deadly to them. Green patches are green sulfur bacteria. The rust patches are colonies of purple non sulfurbacteria. The red patches are purple sulfur bacteria.
Chemosynthetic bacteria use the sulfur in the “smoke” for energy to make ATP.
Kingdom Eubacteria • Can have one of three basic shapes • Bacilli – rod-shaped • Spirilla – spiral-shaped • Cocci – sphere-shaped • Can live in colonies • Strepto – in chains • Staphylo – grape-like clusters • Diplo – pairs
Diplo-bacteria occur in pairs, such as the diplococcus bacteria that causes gonorrhea
Staphylo - occur in clumps, such as this staphylococcus that causes infections of cuts
Strepto- occur in chains of bacteria, such as this streptococcus bacteria that causes some types of sore throats
Cyanobacteria You may have seen them as "green slime" in your aquarium or in a pond. Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria.
The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification. • Bacteria stained purple/violet are Gram + - their cell walls have thick peptidoglycan. • Bacteria stained pink are Gram – - Their cell walls have thin peptidoglycan and lipopolysaccharides.
Eubacteria - Nutrition and Growth • Heterotrophic or Autotrophic • Some are Photoautotrophs – Use sunlight for Energy • Some are Chemoautotrophs. • Many are Obligate Anaerobes. (live w/o O2) • Ex. Clostridium tetani – Tetanus • Some are Faculatative Anaerobes (can live w/ or w/o O2) • Ex. Escherichia Coli • Some are Obligate Aerobes (need O2 to survive) • Ex.) Mycobacterium tuberculosis
BACTERIA REPRODUCES BY FISSION First the chromosomal DNA makes a copy The DNA replicates
NEXT THE CYTOPLASM AND CELL DIVIDES The two resulting cells are exactly the same
In addition to the large chromosomal DNA, bacteria have many small loops of DNA called Plasmids
Bacteria can reproduce sexually - conjugation or asexually - binary fission.
19.3 Diseases Caused by Bacteria Key Concepts: How do Bacteria cause disease? How can Bacterial growth be controlled? Vocabulary: Pathogen, Vaccine, Antibiotic
Microorganisms Cause Disease • The Who • Louis Pasteur – French Chemist • Disproved Theory of Spontaneous Generation • Chapter 1 – What is it? • Germ Theory of Disease • Observed and hypothesized that microorganisms caused infection and disease • Encouraged doctors and surgeons to sanitize and sterilize themselves and equipment
Microorganisms Cause Disease • The How • Some Bacteria need room to grow and reproduce, in order to do so, they destroy living tissue for food • Other types of bacteria create toxins during growth and development which can destroy living tissue • Disease results when bacteria interfere with an organisms ability to function properly.
Helicobacter pylori is the pathogenic bacteria that can causes ulcers
Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers.
Antibiotics • Anti – against • Bio- life • = against life, so antibiotics will only kill living things, which means they are ineffective against viruses (which aren’t alive) • How do they work? • They block the growth and reproduction of bacteria
Vaccines • An injection of a weakened of killed pathogen • Prompts the body to begin the primary immune response • What is the Primary Immune Response? • Secondary Immune response is then activated • What is the Secondary Immune Response? • Once the person comes in contact with the bacteria for a 2nd time, they will have antibodies ready and present to fight the disease
How to kill Bacteria • Sterilization by Heat – Most bacteria can not survive high temperatures, so pathogens will be killed by exposure to high heat • Disinfectants – chemical solutions that kill pathogens • Food Storage/Processing – • Refrigerator storage slows bacterial reproduction • Boiling, Frying, Steaming – heat food to the point at which bacteria will be killed • Preserved food – use of vinegar, salt and sugar to prevent food from spoiling due to bacterial contamination
Some Final Information • Because antibiotics have been overused, many diseases that were once easy to treat are becoming more difficult to treat. MRSA • Some Bacteria are Useful • Ex. Producing and Processing food • Breaking down dead organic material • Make unripened cheese like ricotta and cottage by breaking down the protein in milk.
