Variety of living things

• What are the main groups of organisms mentioned in the study material?

  Plants, animals, fungi, bacteria, protoctists, and viruses
• What are the main features of plants?

  • Multicellular
  • Cells contain a nucleus with a distinct membrane
  • Cells have cell walls made of cellulose
  • Cells contain chloroplasts for photosynthesis
  • Feed by photosynthesis
  • Store carbohydrates as starch or sucrose
  • Do not have nervous coordination
• What are the main features of animals?

  • Multicellular
  • Cells contain a nucleus with a distinct membrane
  • Cells do not have cellulose cell walls
  • Cells do not contain chloroplasts
  • Feed on organic substances made by other living things
  • Often store carbohydrates as glycogen
  • Usually have nervous coordination
  • Able to move from place to place
• What are the main features of fungi?

  • Usually multicellular, some are single-celled (e.g. yeast)
  • Multicellular fungi made of thread-like structures called hyphae
  • Cells contain a nucleus with a distinct membrane
  • Cells have cell walls made of chitin
  • Cells do not contain chloroplasts
  • Feed by secreting extracellular digestive enzymes (saprotrophic nutrition)
  • Some fungi are parasitic
  • Some store carbohydrates as glycogen
  • Do not have nervous coordination
  • Examples include moulds, mushrooms, and yeasts
• What are the main features of protoctists?


  • Diverse kingdom of organisms
  • Mainly microscopic and single-celled, some form colonies or chains
  • Cells contain a nucleus with a distinct membrane
  • Some have features like animal cells (e.g. Plasmodium)
  • Some have features like plant cells (e.g. green algae)
  • Some protoctists photosynthesize, others feed on organic substances
  • Do not have nervous coordination
  • Examples include amoeba, Paramecium, Plasmodium, Chlorella
• What are the main features of bacteria?

  • Microscopic single-celled organisms
  • Have a cell wall, cell membrane, cytoplasm, and plasmids
  • Lack a nucleus but contain a circular chromosome of DNA
  • Some can carry out photosynthesis, most feed off other organisms
  • Example: Lactobacillus
• What are the main features of viruses?

  • Small particles, smaller than bacteria
  • Parasitic and can reproduce only inside living cells
  • Infect every type of living organism
  • Have a variety of shapes and sizes
  • No cellular structure, have a protein coat and contain nucleic acid (DNA or RNA)
  • Example: Influenza
• What is the definition of a pathogen?


  A pathogen is any microorganism that causes disease in another organism.
• What types of microorganisms can be pathogens?

  • Bacteria
  • Fungi
  • Protoctists
  • Viruses