Holozoic nutrition

• What is holozoic nutrition?

  -internal digestion

  -involves enzymes
• What are the 5 stages of holozoic nutrition?

  1. Ingestion (taking food in)
  2. Digestion (breaking food down)
  3. Absorption (moving nutrients into the blood)
  4. Assimilation (using the absorbed nutrients)
  5. Egestion (removal of undigested food- NOT WASTE)
• Label this diagram

  A) Nucleus

  B) Food particle

  C) Psuedopodia

  D) Food vacule

  E) Ingestion

  F) Digestion

  G) Absorption

  H) Assimilation

  I) Egestion

  
• What are psuedopodia?

  Temporary extensions of an amoeba's cytoplasm
• How do amoeba ingest their food?

  Endocytosis: amoeba uses its pseudopodia to engulf its prey
• What happens for digestion to occur in an amoeba?

  -engulfed prey is totally enclosed within a food vacuole of the cytoplasm

  -fusion of food vacuole with vesicle containing digestive enzymes
• Where does absorption of nutrients occur in an amoeba?

  From the food vacuole into the cytoplasm
• What is hydra?

  A cylindrical multicellular eukaryote that has tentacles at the top surrounding its mouth, the only body opening.
• Where does digestion occur in hydra?

  The hollow body cavity
• How does hydra ingest food?

  -extends its tentacles

  -discharges stinging cells and paralyses prey

  -the tentacles move the food through the mouth into the hollow body cavity
• The first stage of digestion in hydra is extracellular, as the cells secrete enzymes into the body cavity. The final stage of digestion is intracellular, as food is taken into cells and digested here