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Explore the diverse world of bacteria, from ancient fossils to modern species, their shapes, and how they reproduce. Learn about different types of bacteria and their roles in nature and human health. Discover fascinating facts about these microorganisms.
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BACTERIA Chapter 19.1
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 • Staphylo – grape-like clusters • Strepto – in chains
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 are Gram + - their cell walls have thick petidoglycan. • Bacteria stained pink are Gram – their cell walls have 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 • Temperature requirements • Some are Thermophilic, Some prefer acidic envmt.
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.
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.
Some Final Information • Because antibiotics have been overused, many diseases that were once easy to treat are becoming more difficult to treat. • 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.