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Living Things

Living Things. 1.7 million species been classified suggested around 8.8 million species all are put into groups based on genetics 3 main domains (groups) are: Archaea & Eubacteria – prokaryotes Eukaryotes BiologySource. Prokaryotes – 2 Kingdoms. Formerly 1 kingdom - Monera

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Living Things

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  1. Living Things • 1.7 million species been classified • suggested around 8.8 million species • all are put into groups based on genetics • 3 main domains (groups) are: • Archaea & Eubacteria – prokaryotes • Eukaryotes • BiologySource

  2. Prokaryotes – 2 Kingdoms • Formerly 1 kingdom - Monera • Archea – primitive bacteria • Eubacteria – more developed • earliest life on earth • diverged from common ancestor ~ 4 bya • eukaryotes diverged millions yrs later

  3. Eukaryotes – 4 Kingdoms • Plant, Animal, Fungi, Protists

  4. 1. Archea • can live in extreme conditions • thermophiles – hot temp like hydrothermal vent • halophile – salty environments like Dead Sea

  5. psycrophiles – live at cold temp (Antarctic lakes) • acidophiles – can tolerate pH 0 • some live in normal temp and environments • most are methanogens – absorb CO2, N2, or H2S and give off methane • doesn’t require sunlight or oxygen

  6. 2. Eubacteria • “true” bacteria • microscopic • ex cyanobacteria (blue-green algae) on earth for over 3 billion years • able to carry out photosynthesis (produces oxygen) • oxygen conc of atmosphere increased allowing oxygen breathers (animals) to survive

  7. Uses of Eubacteria • digestion in intestines • yoghurt/cheese production • fermentation (wine, beer, pickling…) • wastewater/oil spill/toxic spill treatment • BiologySource • decomposers

  8. Dangerous Eubacteria • cause health problems: • strep throat • food poisoning (E. coli and salmonella)

  9. Structure & Function of Bacteria • microscopic • smallest living cells • classified according to: • cell shape • cell wall structure • motility (way of moving)

  10. 1. Cell Shape • 3 basic cell shapes • spherical – “cocci” • rod-shaped – “ bacilli” • spiral – “spirochetes”

  11. prefixes are added to show living arrangement of bacteria • strepto – chain • stphlyo - cluster

  12. CAN YOU NAME IT??? diplococcus staphylococcus streptococcus

  13. 2. Cell Wall Structure • 2 kinds of cell walls, appear different when stained with Gram stain • peptidoglycan – thick coat of sugars, makes wall strong & rigid (Gram postive) • less peptidoglycan (Gram negative)

  14. Movement • various methods: • most mobile bacteria use flagella (whip-like tail) • others secrete mucous can glide on

  15. Typical Bacteria

  16. How Bacteria Reproduce • Asexual - Binary Fission • 1 original cell splits into 2 • can occur in 20 minutes for many bacteria species. • In 12 hours, 1 bacterium can divide to form a colony of 68 billion cells. • overcrowding, waste, and food availability do not allow populations to grow this large. • produces colonies of bacteria that are genetically identical.

  17. 2. Types of Sexual Reproduction • Transformation: bacteria pick up stray DNA from their surroundings. • Conjugation: two bacterial cells join (= conjugate) to exchange genetic material (plasmids, separate from main DNA)

  18. 3. Transduction: viruses that infect bacteria transmit genetic material from another source • Endospores form when environmental conditions make normal functions too difficult.

  19. Viruses: Structure and Function • Viruses not considered to be living organisms. • have DNA and RNA, and can adapt to change. • made of proteins and nucleic acids, not cells. • must use a host cell to reproduce. See page 29

  20. structure of virus allows it to enter host cell and reproduce • many shapes and sizes. • usually classified by the type of cell they infect. • protein coat is like the key to a specific cell membrane, e.g., HIV only infects T cells of the immune system. • Sometimes, (avian flu virus) protein coat is a master key. • Bacteriophages enter and infect bacteria, used in biotechnology and gene therapy.

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