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Bacteria

Delve into the realm of bacteria, Earth's invisible pioneers, and learn how their diverse forms and functions influence human health, food production, and medicine. Explore the essential concepts of bacterial structure, reproduction, and their pivotal role in the cycle of life.

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Bacteria

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  1. Bacteria Our invisible friends

  2. Germ Theory of Disease • Joseph Lister – Aseptic Techniques • Robert Koch – Germ Theory • A specific microorganism causes a specific disease

  3. Bacteria are prokaryotes • Pro – before • Karyon – nucleus • The simplest forms of life are prokaryotes. • Earth’s first cells were prokaryotes.

  4. Lots of Them! • Prokaryotes are Earth’s most abundant life forms. • They can survive in many environments. • They can get energy from many different sources.

  5. Prokaryote Review • Mostly single-celled • No nucleus or organelles • Circular chromosomes • Cell walls • Reproduce mostly asexually • Anaerobic or aerobic • Heterotrophic or autotrophic

  6. Archaebacteria • Methane producers – anaerobic • Halophiles • Halo = salt • Philia = love • Thermophiles • Thermo = heat

  7. Eubacteria • Parasitic heterotrophs (Streptococcus) • Saprophages • Sapro = death • Phage = eat • Cyanobacteria (blue-green algae) • Photosynthetic • Chemosynthetic autotrophs (Rhizobium)

  8. Bacteria Structure Chromosomes – found in cytoplasm Pili – hairlike structures made of protein; help bacteria attach to surfaces Capsule – layer outside cell wall; protects cell from white blood cells and antibiotics; keeps the cell from drying out

  9. Bacteria Structure

  10. Bacteria are Named by Shape • Cocci (ball-shaped) • Streptococcus mutans • Bacillus (rod-shaped) • Clostridium botulinum • Spirilli (spiral-shaped) • Treponema palladium

  11. Bacteria Reproduction Binary fission – asexual; division of bacteria into two identical cells Conjugation – sexual; two prokaryotes attach to each other and exchange genetic material; creates diversity among bacteria

  12. Bacteria Reproduction

  13. Bacteria Reproduction

  14. Why do we need bacteria? Our bodies use bacteria – not harmful; help prevent harmful bacteria from causing disease Foods – cheese, pickles yogurt all made with bacteria Medicines – make antibiotics such as penicillin

  15. Disease Causing Bacteria Only a small percentage of bacteria is harmful Cause disease in two ways: 1. multiply quickly so the body cannot defend itself ex. STDs, strep throat, acne 2. secrete a toxin that can be harmful ex. Cavities – use sugar for energy and secrete acid which can harm teeth

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