Question

A phylum common to unicellular plants and animals is

• A. Fungi
• B. Plantae
• C. Monera
• D. Protista

Answer 1

Answer: (D)

General characteristics of Kingdom Protista are as follows:

• They are simple eukaryotic organisms.
  
• Most of the organisms are unicellular, some are colonial and some are multicellular like algae.
  
• Most of the protists live in water, some in moist soil or even the body of human and plants.
  
• These organisms are eukaryotic, since they have a membrane bound nucleus and endomembrane systems.
  
• They have mitochondria for cellular respiration and some have chloroplasts for photosynthesis.
  
• Nuclei of protists contain multiple DNA strands, the number of nucleotides are significantly less than complex eukaryotes.
  
• Movement is often by flagella or cilia.
  
• Protists are multicellular organisms, they are not a plant, animal or fungus.
  
• Respiration- cellular respiration is primarily aerobic process, but some living in mud below ponds or in digestive tracts of animals ares strict facultative anaerobes.
  
• Nutrition- they can be both hetreotrophic or autotrophic.
  
• Flagellates are filter feeding, some protists feed by the process of endocytosis (formation of food vacuole by engulfing a bacteria and extending their cell membrane).
  
• Reproduction- some species have complex life cycle involving multiple organisms. Example: Plasmodium. Some reproduce sexually and others asexually.
  
• They can reproduce by mitosis and some are capable of meiosis for sexual reproduction.
  
• They form cysts in adverse conditions.
  
• Some protists are pathogens of both animals and plants. Example: Plasmodium falciparum causes malaria in humans.
  
• Protists are major component of plankton.