1.3: Recall the term ‘Pathogen’ and know that Pathogens may be Fungi, Bacteria, Protoctists or Viruses

PATHOGENS: Micro-organisms that causes Diseases

COMMON PATHOGENS

FUNGI Both Multicellular and Unicellular Stores Carbohydrates as Glycogen Cell walls are made of Chitin DO NOT carry out Photosynthesis Organised into a Mycelium: Thread-like structure called Hyphae, which contains many Nuclei They feed by Extracellular Secretion: Releases digestive enzymes onto food and absorb organic products ( saprotrophic nutrition ) Example: Mucor / Yeast

BACTERIA Unicellular Organisms Lack in Nuclei’s so has circular chromosomes of DNA called Plasmids Has Cell wall, Cell membrane, Cytoplasm SOME can carry out Photosynthesis Feeds by eating living or dead living Organisms Example: Lactobacillus Bulgaricus (Yoghurt Production)

PROCTISTS Microscopic Unicellular Organisms Example: Animals: Amoeba                            Plants: Chlorella

VIRSUS Small Particles ( smaller than Bacteria ) Parasitic: can only reproduce in living Organisms They only reproduce infect every type of living Organisms They have a wide variety of shapes and sizes No Cellular structure Has protein coat Contains one type of Nucleic Acid ( RNA or DNA ) Example: Tobacco Mosaic Virus / HIV                          Plants: Chlorella