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Nutrient Assimilation 3: Gathering the Goodies!

This text explores nutrient assimilation in unicellular organisms, focusing on how small, non-polar molecules diffuse through plasma membranes, while larger molecules are ingested through specialized membrane regions. Key examples include the cichlids of the East African Rift Lakes, which display a diverse diet consisting of algae, plankton, and more, along with the evolution of specialized pharyngeal jaws to match their feeding behavior. The discussion extends to the symbiotic relationships in organisms like termites, which rely on protozoan and bacterial partners for digestion.

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Nutrient Assimilation 3: Gathering the Goodies!

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  1. Nutrient Assimilation 3:Gathering the Goodies! Text Pages 961 - 965

  2. Unicellular Organisms Small and non-polar molecules transported or diffuse through plasma Larger molecules ingested with aid of specialized regions of the membrane

  3. Note the Oral Apparatus

  4. Note the Oral Apparatus

  5. Phagocytosis

  6. Feeding apparatus http://icte.umsl.edu/MO-STEP/lessons/beaks.html

  7. Cichlids of the East African Rift Lakes

  8. East African Rift Lakes

  9. Home to Cichlids, > 300 species • Cichlid food sources include leafy algae, crust forming algae, plankton, fish, plants, snails, fish eggs, and plants! • Each species evolved specialized pharyngeal jaws Fig 43.4

  10. Cichlid Pharyngeal Jaws Fig 43.4

  11. Fig 41.2

  12. Always be ready for any surprises in life...

  13. Always be ready for any surprises in life...

  14. Other teeth

  15. Teeth!

  16. More Teeth Dentition evolved to meet feeding behaviors and diet. Also note claw evolution!

  17. Mammalian Jaws

  18. Digestion: meat vs. plant material

  19. Herbivore vs. Carnivore

  20. Enzymes to match the meal! End products and transport mechanisms

  21. If you don’t have the enzymes, Termites eat wood but lack cellulase Termites! • So they rely on a protozoan, Mixotricha, which in turn relies upon at least 4 types of bacteria!

  22. Mixotricha, a protozoan

  23. Mixotricha: bacterial symbionts • Treponema attached to cell surface for locomotion • Rod shaped bacteria on the surface (protection?) • Spherical bacteria as internal endosymbionts to function as mitochondria! • Mixotricha lacks mitochondria!

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