DRKS111_LE2

• Protozoans


  • Lack a cell wall - not plant
  • Many carry photosynthetic plastids - not animal
  • Have at least one motile stage in life cycle
  • Most ingest their food
  • Carry on all life activities within a single cell
• Endoplasma


  Nucleus and cytoplasmic organelles
• Ectoplasm


  • More transparent
  • Contains bases of cilia or flagella
• Nucleus


  • Membrane bound organelle
  • Contains DNA
  • Macronuclei of ciliates controls all cell functions except reproduction
  • Micronucleus controls reproduction
• Locomotion


  • Cilia and flagella
  • Pseudopodia (Lobopodia, Limax Form, Filopodia, Reticulopodia)
  • Axopodia
• Cilia


  Propel water parallel to the cell surface
• Flagella


  Propel water parallel to the flagellum axis
• Cilia and flagella


  • Morphologically the same
  • 9 pairs of microtubules around a central pair
• Asexual Reproduction


  • Binary fission
  • Multiple fission - schizogony
  • Sporogeny
  • Budding
• Sexual Reproduction


  • Isogametes
  • Anisogametes
  • Syngamy
  • Autogamy
  • Conjugation
• Encystment


  • Surviving in harsh conditions
  • Form cysts - dormant forms that shut down metabolism and have a resistant external covering
• Excystment

  Escape from cysts when environmental conditions are favorable
• Flagellated phylums
• Giardia lamblia causes diarrhea in humans from drinking water contaminated with sewage
• Trichomonas vaginalis infects urogenital tubes in humans and is sexually transmitted, with no symptoms in men but vaginitis in women
• Trypanosoma


  • Causes sleeping disease in humans
  • Glossina (tsetse fly) is the vector
  • Bushbuck is reservoir source
  • Annually ±10 000 cases (half is fatal and remainder sustain permanent brain damage)
  • Parasitemia is the quantitative content of parasites in the blood and used as a measurement of parasite load
• Red tide caused by Ceratium
• Characteristics of Phylum Ciliophora

  • Ciliates are the most diverse and specialized protozoans
  • Larger than most other protozoa
  • Most free-living, some commensal and parasitic
  • Usually solitaire and motile
  • Most free-living in freshwater or marine habitats
• Balantidium coli lives in the intestine of humans, pigs, and rats, and can cause dysentery
• Entodinium and Nyctotherus live in the tracts of ruminants and frogs
• Ichthyophthirius causes the fish disease "ick" (whitespot)
• Eimeria infects birds and causes diarrhea, which can be fatal for young birds
• Toxoplasma gondii is a cat parasite that can cause few or no effects in humans, except in AIDS patients and pregnant women (birth defects)
• Sarcodina


  • Classification not sorted out yet - researchers busy comparing morphological characteristics with molecular data
  • Amoeba proteus - having no definite form
  • Proteus: [Greek Mythology. A sea god who could change his shape at will]
• Skeletons of dead organisms sink to the bottom of the ocean, forming land like the White Cliffs of Dover
• Phylogeny and adaptive radiation is the evolutionary expansion (diversification) that forms many ecologically different descendants from a single ancestor in a short geological time
• Microtubules


  Hollow, tubular structures made up of tubulin proteins. Provide structure and shape to cells and play a role in cell division and intracellular transport. In cilia and flagella, there are 9 pairs of microtubules around a central pair.
• Microfilaments


  Solid, rod-like structures made up of actin proteins. Thinner than microtubules, they play a role in cell movement and shape changes, such as cell division and muscle contraction. Not present in cilia and flagella.
• Isogametes

  Gametes that are similar in size and shape, produced by isogamous organisms.
• Gametogenesis

  The process of producing gametes through meiosis, resulting in haploid sperm and eggs.
• Examples of flagellated filum

  Chlorophyta, Euglenozoa, Apicomplexa, Ciliophora, Dinoflagellata, Amoebozoa, Foraminifera
• Binucleate Zygote


  A zygote that contains two nuclei, which can occur in some types of sexual reproduction, such as in the life cycle of certain algae and fungi.
• Syngamy


  The process of cell fusion or the fusion of two gametes to form a single cell, known as a zygote.
• Autogamy


  A type of sexual reproduction where an organism fertilizes itself by fusing its own male and female gametes
• Allogamy


  A type of sexual reproduction where the male and female gametes are produced by different individuals, leading to genetic diversity in the offspring
• Binucleate zygote


  A zygote that contains two nuclei, which can occur in some types of sexual reproduction, such as in the life cycle of certain algae and fungi.
• Zygote


  A cell that results from the fusion of two gametes in sexual reproduction. A zygote contains all the genetic material necessary to develop into a new organism.