variety of living organisms

• understand the term pathogen and know that pathogens may include fungi, bacteria, protoctists or viruses

  a pathogen is an organism that causes infection or disease to its host
• plants

  multicellular organisms

  cells contain chloroplasts to carry out photosynthesis

  cells have cellulose cell walls

  they store carbohydrates as starch or sucrose

  eg flowering plants eg cereal

  eg herbaceous legume eg peas / beans
• animals

  multicellular organisms

  do not contain chloroplasts so can not carry out photosynthesis

  no cell walls

  nervous coordination and can move from one place to another

  store carbohydrates as glycogen

  eg mammals and insects
• fungi

  can not carry out photosynthesis

  organised into a mycelium made from thread like structures called hyphae which contain many nuclei

  eg are single celled

  cells have walls made of chitin

  they feed by extracellular secretion of digestion enzymes onto food material and absotption of the organic [roductd known as saprotrophic nutrition

  store carbohydrates as glycogen

  eg mucor whoch has thr tpical fungal hyphal sturcture and yeast whichis single celled
• protoctists

  microscopic single celled organisms

  a pathogenic eg is plasmodium responsible for causing malaria
• viruses and pathogens


  -they enter living cells and make the cells make new copies of the virus

  -they dont grow of feed like other organisms so we cant say they are living

  -they dont have the characteristics : reproduction and nutrition
• four types of pathogenic microbe

  -bacteria

  -viruses

  -protozoan

  -fungi
• where can microbes reproduce rapidly

  in warm places with plenty of nutrients
• bacteria are tiny living cells

  they have a cell wall and no nucleus
• viruses can invade cells


  and make them produce thousands of identical viruses
• Fungi


  Multi-celled organisms that can cause infections on the skin or inside the body.
• Bacteria


  Single-celled organisms that can cause a variety of illnesses, such as food poisoning or pneumonia.
• Protoctists


  Single-celled organisms that can cause diseases like malaria.
• Viruses


  Even smaller organisms that need to be inside a host cell to multiply; can cause many different diseases, from the common cold to HIV/AIDS.